Grenville-age A-type and related magmatism in southern Laurentia, Texas and New Mexico, U (Anorthosite�Mangerite�Charnockite�Granite) suites present in the Grenville province of eastern Laurentia. � 2006 Elsevier B.V. All rights reserved. Keywords: Grenville; Southern Laurentia; U�Pb; A-type; AMCG
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A-type granites (including their volcanic equivalents) and related rocks (mafic intrusions, massif-type anorthosite, basaltic dikes and lavas, rare alkaline rocks) form a conspicuous part of the granite spectrum. They have been recognized by the geological community only relatively recently (first definition of A-type ...
NASA Astrophysics Data System (ADS)
The formation of accessory phosphates in granites reflects many chemical and physical factors, including magma composition, oxidation state, concentrations of volatiles and degree of differentiation. The geotectonic setting of granites can be judged from the distribution and character of their phosphates. Robust apatite crystallization is typical of the ...
A zircon U-Pb age of 120.2 � 1.7 Ma has been dated by ion microprobe in situ for the Laoshan A-type granite in eastern China. Fossil 231Pa excess has been inferred to explain the observed 207Pb-208Pb decoupling for alkali feldspar. In order to reconcile the apparent paradox of fossil 231Pa excess for alkali feldspar rather than for zircon, two ...
A number of small Palaeoproterozoic granitoid plutons were emplaced in the Khetri Copper Belt, which is an important Proterozoic metallogenic terrane in the northeastern part of Aravalli mountain range. Contiguous Biharipur and Dabla plutons are located about 15 km southeast of Khetri, close to a 170 km long intracontinental rift zone. The plutons are composed of amphibole-bearing alkali-feldspar ...
The Victoria Valley Batholith, a granite rhyolite complex of unusual composition, was emplaced in the Grampians Stavely Zone of western Victoria at 396 Ma. Petrographic and geochemical features of the suite share important similarities with A-type magmas and we propose that they be classified as such. The close association between metaluminous to weakly peraluminous ...
Plutonic rocks in the Central Alaska Range were emplaced during important tectonic events including the end of Late Cretaceous-Paleocene arc magmatism, the terminal phase of terrane accretion, ridge subduction, strike- slip faulting, oroclinal rotation of western Alaska, and resumption of arc magmatism during Eocene time along the proto-Aleutian arc ...
The Mesozoic geology of SE China is characterized by widespread Jurassic to Cretaceous igneous rocks consisting predominantly of granites and rhyolites and subordinate mafic lithologies. However, the tectonic regime responsible for the inland Jurassic granites remains controversial. We report here U Pb zircon ages, geochemical and Sr Nd Hf isotopic data ...
... SEDIMENTARY ROCK, DEPOSITION, GEOLOGIC AGE DETERMINATION, SANDSTONE, CLAY, GRANITE, VOLCANOES, DEPOSITS, IGNEOUS ...
DTIC Science & Technology
The Saldania Belt (SB), located in the southernmost part of South Africa, contains S-, I-, and A-type granites. Whole-rock Sm�Nd data for the Saldania granites indicate the presence of a juvenile as well as inherited crustal signature. The earlier S-type granites have ?Nd( t) values from ?4.2 to ?3.28 (for t = 550 Ma). In contrast, ...
The Piquiri Syenite Massif, southernmost Brazil, is part of the post-collisional magmatism related to the Neoproterozoic Brasiliano-Pan-African Orogenic Cycle. The massif is about 12 km in diameter and is composed of syenites, granites, monzonitic rocks and lamprophyres. Diopside-phlogopite, diopside-biotite-augite-calcic-amphibole, are the main ...
PubMed
The Furong tin deposit, located in southern Hunan Province, China, is a large, newly discovered deposit with an estimated Sn reserve of about 700,000 tons. The deposit is spatially and temporally associated with the A-type Qitianling granite. The 3He/4He ratios of fluid inclusions trapped in sulfides from the deposit range from 0.13 to 2.95 Ra, indicating a mixed crust-mantle ...
The Serra da Graciosa Granites and Syenites comprise five distinct plutons in the Brasiliano/Pan-African Graciosa A-type Province, southern Brazil. Six petrographic series can be identified in these plutons: (1) Alkaline series 1, composed of amphibole-bearing alkali feldspar syenites with varied mafic mineralogy and quartz contents, from alkali feldspar ...
The Songpan Garze fold belt covers a huge triangular area (> 200,000 km2), confined by the South China (Yangtze), North China and Tibetan Plateau continental blocks. In the Songpan Garze fold belt, Triassic adakitic granitoids have been identified. However, whether there are Triassic A-type granites is unclear. Here, we report our first finding of an ...
The Serbo-Macedonian Massif belongs to the Internal Hellenides, and is subdivided into two units: the Kerdyllia and Vertiskos Unit in the eastern and central and northwest Chalkidiki Peninsula (Macedonia, Greece), respectively. The Vertiskos Unit mostly comprises various types of gneisses, associated with amphibolites and metasediments, and it is intruded mainly by Mesozoic leucocratic ...
... Density of the rocks is a suitable variable for ... magmatic granitic intrusions is discussed ... For the classical model involving intrusion of a homogeneous ...
This paper acts as a rebuttal to comments made by other scientists regarding the origin of the Poimena Granite as discussed in an earlier paper by these authors. The Lottah Granite and the enclosing Poimena Granite of northeastern Tasmania represent one of the best documented and most intensely Li-F-rich alkali-feldspar ...
Energy Citations Database
The bedrock of western Dronning Maud Land, Antarctica records several stages of anorogenic magmatism. The Grenvillean-age metamorphic basement gneisses of Heimefrontfjella and Mannefallknausane were intruded by mafic dikes (Bauer et al., 2003) and A-type granite plutons (Jacobs, 1991) at circa 1 Ga. A 590 Ma suite of mafic dikes manifests a subsequent ...
The anorogenic Damaraland intrusive complexes in Namibia belong to the bimodal Paran� Etendeka Large Igneous Province and comprise mafic, silicic and alkaline plutonic and volcanic rocks that were emplaced into the Neoproterozoic Damara orogenic belt at 124 to 137 Ma. The magmatism was related to the Tristan mantle plume and continental rifting that led to separation of ...
The Graciosa Province comprises more than 20 A-type granitic and syenitic plutons in southern Brazil. This province was emplaced during a period of tectonic change, with A-type magmatism post-dating syntectonic I- and S-type magmatism to the east. Dating the age of magmatism has proven ...
The late Paleozoic-early Mesozoic granites in Daqingshan district of the northern margin of north China plate is classified into six types as follows.Aguigou intrusion is consists of gabbro, diorite, quartz diorite, and granodiorite.Its feature is rich in mafic compositions.The formation age is 284.5�2.9Ma or 283.7�3.7Ma for the quartz diorite, and 281.1�3.4Ma for ...
Rapakivi granites characteristic practically of all old platforms are greatly variable in age and irregularly distributed over the globe. Four types of magmatic associations, which include rapakivi granites, are represented by anorthosite-mangerite-charnockite-rapakivi granite, ...
Granitoid plutons of the Khetri complex have been studied for zircon U-Pb and Pb-Pb thermal ionisation mass spectrometry methods along with the whole-rock geochemistry to provide new constraints on the Palaeoproterozoic magmatic activity in the Aravalli orogen of northwestern peninsular India. The rocks are metaluminous to weakly peraluminous, largely ferroan and intraplate ...
provides a critical data point for the Huayna Potosi� granite at 5400 m, clarifying previous in the central Andean plateau of Bolivia. In the 4� 6 km high Cordillera Real, numerous granites and SW directed boundary. U-Pb zircon analyses indicate Permo-Triassic granitic magmatism, with less extensive ...
The Late Permian (260 Ma) Emeishan large igneous province of SW China contains numerous magmatic Fe-Ti oxide deposits. The Fe-Ti oxide deposits occur in the lower parts of evolved layered gabbroic intrusions which are spatially and temporally associated with A-type granitic rocks. The 260 Ma Panzhihua layered gabbroic intrusion hosts one of the largest ...
The Late Proterozoic plutonic complexes of northeastern Egypt belong to a number of magma types of variable tectonic regimes, and exhibit a variety of phyllosilicate minerals. The results show that the phyllosilicates define three compositionally distinct groups. Phyllosilicates in the anorogenic peralkaline granites, which were developed from a hypersolvus felsic melt, are ...
New geochemical, isotopic, and geochronological data and interpretations are presented for late Neoproterozoic intrusive carbonates and related rocks of southern Sinai, Egypt (northernmost Arabian-Nubian Shield). The Tarr carbonates are coarsely crystalline and related to explosive emplacement of hypabyssal and volcanic albitite at 605 � 13 Ma. The carbonates associated with the albitites are ...
The intrusive rocks in Anatolia occupy a broad petrological range from I- to A- type granitoids. Thus, Turkey is a natural laboratory to study collision-related magmatism, its geochemical characteristic, source region and also tectono-magmatic evolution. The central, northwestern and western Anatolian ...
The Late Permian (260 Ma) Emeishan large igneous province of SW China contains three nearly identical gabbro-granite complexes which host giant Fe-Ti oxide deposits. The Fe-Ti oxide deposits are within the lower portions of evolved layered gabbroic intrusions which are spatially and temporally associated with A-type granitic plutons. Previous studies have ...
This study, based on the systematic mapping of the planes and lines of magmatic fluidality, of the intensity of these structures and of the quartz microstructures, leads to a geometric and kinematic model for the emplacement of the leucogranitic complex. ...
National Technical Information Service (NTIS)
The Tien Shan (Tianshan) orogen formed during Late Palaeozoic collision between the Karakum Tarim continent and the Paleo-Kazakhstan continent, a Caledonian component of the Altaid Collage. The Southern Tien Shan terrane represents an intensely deformed fold and thrust belt formed after the final closure of the Paleo-Turkestan ocean. In the Late Carboniferous Early Permian the Tien Shan was ...
On the basis of studying the concentration and dispersion characteristics of U, Au, and Si in the granite area of Northern Guangdong and Southern Jiangxi in combination with the model experiments of magmatic and hydrothermal systems, the spatial distribut...
Aug 5, 2002... is unlikely that the domes are granite plutons, it is possible that they do represent some other shallowly emplaced magmatic intrusion. ...
NASA Website
The Kanigiri Pluton (6.2 � 2.1 km2; 995 Ma) occurs close to a major fault and is intrusive into the meta-volcanics in the western margin of the Nellore Khammam schist belt in Andhra Pradesh, India. The dominantly metaluminous pluton displays geochemical characteristics of A-type granites, including high abundances of Nb, Zr, Y, Ta, and REE (except Eu), and low concentrations ...
, and with broadly con- temporaneous granite magmatism) and quasi- continuous bimodal magmatism with only rare. Epsilon neodymium values point toward largely crustal sources for most Australian felsic igneous rocks-undepleted granites and (B) rare Sr-undepleted, Y-depleted granites. The geo- ...
Granitic plutonism is the principal agent of crustal differentiation, but linking granite emplacement to crust formation requires knowledge of the magmatic evolution, which is notoriously difficult to reconstruct from bulk rock compositions. We unlocked the plutonic archive through hafnium (Hf) and oxygen (O) isotope analysis of zoned ...
Allanite and chevkinite perrierite are important accessory phases in the granitic and syenitic A-type rocks of the Graciosa Province, southern Brazil. Allanite (Ce) is the main REE phase in the granites of the aluminous association which includes metaluminous to weakly peraluminous granites while chevkinite ...
There are large-scale magmatism and metallogenic processes in Southeast China, where has been generally considered to posses the characteristics of large igneous province. As a major part of East Asia, Southeast China is very complex region involving multiple stages of the Mesozoic tectono-magmatic activity. Various tectonic models have been proposed in ...
In the calculations we have assumed that all apatites are magmatic. The presence of chlorite and altered plagioclase within the granite and quartz-monzodiorite suggests that alteration may play a role in leading to erroneous estimates of initial melt Cl and F for 2 reasons: (1) the apatites may in fact not be magmatic in origin, but ...
DOE Information Bridge
Anisotropy of magnetic susceptibility and structural geology of the ca. 1.45 Ga Karlshamn pluton (southern Sweden) are used to study its emplacement and structural evolution. The Karlshamn pluton is one of the largest metaluminous A-type granitoid intrusions in southern Sweden. It is a multiphase body made up of two suites that differ in composition but which have similar ...
Oxygen and hydrogen isotope systematics of the Proterozoic Harney Peak Granite were examined in order to constrain its petrogenesis and to examine the role of fluids in a peraluminous granite-pegmatite magmatic system. It is shown that fractional crystallization or subsolidus interaction of the Harney Peak Granite ...
The Songpan Ganzi Fold Belt (SGFB), SW China, was developed from a passive continental margin into an orogenic belt with the consumption of the Paleo-Tethys. During the evolution of the SGFB, numerous Late Triassic granitic plutons formed and exhibited a progressive development from adakite/I-type granite, high Ba-Sr granite, ...
It is possible to study the Mesozoic lithospheric thinning and crust-mantle interaction due to Early Cretaceous intensive magmatism widely developed in the North China Block. As an important part of the Early Cretaceous magmatism in the North China Block, the widespread Early Cretaceous granites in the Dabieshan-Qinlin Orogen, ...
A symposium entitled �A-Type Granites and Rhyolites: Is A for Ambiguous?,� held last May at the AGU 1992 Spring Meeting in Montreal, Canada, provided a forum for continued discussion and scientific debate of the complexities inherent in A-type granites. The concept of A-type granites [Loiselle and Wones, 1979] ...
The external zircon morphology of granitoid rocks is combined with internal structures studied by cathodoluminescence imaging, to test the classic �Pupin method� against geological and geochemical evidence for the origin and evolution of granitic rocks. Granitoids in Central Anatolia display a wide range of petrological characteristics from S-type and I-type to A-type. We ...
The Lottah Granite is a composite pluton of tin mineralized strongly peraluminous alkali-feldspar granite which intrudes the Poimena Granite, a major component of the mid-Devonian Blue Tier Batholith of northeastern Tasmania. Earlier workers interpreted the Lottah Granite as a metasomatised differentiate of the ...
This paper compares the 1.67 1.47 Ga rapakivi granites of Finland and vicinity to the 1.70 1.68 Ga rapakivi granites of the Beijing area in China, the anorogenic �130 Ma granites of western Namibia, and the 20 15 Ma granites of the Colorado River extensional corridor in the Basin and Range Province of southern ...
Granitic intrusions in Eocene and post-Eocene volcanic rocks outcrop in the Northern and Southern Zones of the Eastern Pontides, NE Turkey. Intrusions in the Northern Zone extend NW SE whereas those in the Southern Zone are nearly E W orientated. The contacts of the intrusions with the volcanic rocks are sharp, epidotized and include volcanic xenoliths. The margins of Southern ...
Dronning Maud Land (DML), Antarctica, and southern Mozambique were adjacent areas during the Gondwana supercontinent stage. We have studied rocks from both areas for Sm-Nd and Lu-Hf isotope compositions and dated them with single-zircon U-Pb or plagioclase Ar-Ar methods. Proterozoic rocks of our study are limited to DML and comprise A-type granites, mafic ...
and are invariably associated with A-type granites that formed after peak activity of a magmatic cycle. The deposits consist of ore shells of quartz-molybdenite stockwork veins...
Science.gov Websites
range from granodiorite to granite in composition; the deposits primarily form in continental margin subduction-related magmatic arcs, often concurrent with formation of...
The study area, an activation zone of the median Massif in Xingmeng geosynclinal area, geologically underwent the multiple tectono-magmatic reworking of granitizations during Shinagan, Caledonian, and Hercynian periods and of continental rift volcanism in...
Contents: The timing and geneses of ilmenite-series and magnetic-series granitic magmatism in the north-central Hokkaido, Japan; On some species of Sharpeiceras (Ammonoidea) from the Cretaceous of Hokkaido, Japan; A note on newly found ore fields in Govi-...
The Permian Kalatongke Ni-Cu deposits in the Central Asian Orogenic Belt are among the most important Ni-Cu deposits in northern Xinjiang, western China. The deposits are hosted by three small mafic intrusions comprising mainly norite and diorite. Its tectonic context, petrogenesis, and ore genesis have been highly contested. In this paper, we present a new model involving slab window ...
Mineralogical, geochemical characteristics and Sr-Nd isotopic data are presented for the Namsan A-type granite and Gyeongju I-type granitic rocks in Gyeongju area, Gyeongsan Basin, Korea. The Namsan A-type granite is alkali feldpar granite and consists of quartz, perthite, ...
Airborne magnetic data provide a means for guiding reconstructions of Rodinia, in particular the hotly debated western continuations of Laurentia, such that the magnetic data tie existing isolated interpretations of geologic units through continuous data coverage, provide plate scale views of geology and tectonics and extend interpretations of units buried beneath cover. Recently released digital ...
The Tunk Lake pluton of coastal Maine, USA is a concentrically zoned granitic body that grades from an outer hypersolvus granite into subsolvus rapakivi granite, and then into subsolvus non-rapakivi granite, with gradational contacts between these zones. The pluton is partially surrounded by a zone of basaltic and ...
Earth�s continental crust is dominated by granitic (s. s.) rocks with substantial K2O contents and K/Na > 0.6. However, 75% of Earth�s continental crust formed during the Archaean (4.0�2.5 Ga), as sodic Tonalite-Trondhjemite-Granodiorite (TTG) granitoids (K/Na ~ 0.23). It is generally assumed that the more potassic granites arose by intracrustal ...
The strongly peraluminous, P- and F-rich granitic system at Podles� in the Kru�n� Hory Mountains, Czech Republic, resembles the zonation of rare element pegmatites in its magmatic evolution (biotite ? protolithionite ? zinnwaldite granites). All granite types contain disseminated Nb-Ta-Ti-W-Sn minerals that ...
The P�T record of synchronous magmatism, metamorphism and deformation at Petrel Cove, southern schists in the thermal aureole of the Victor Harbor Granite at Petrel Cove, in the southern Adelaide Fold on the P�T record preserved in porphyroblastic schists at Petrel Cove in the Victor Harbor region
In the calculations we have assumed that all apatites are magmatic. The presence of chlorite and altered plagioclase within the granite and quartz-monzodiorite suggests that alteration may play a role in leading to erroneous estimates of initial melt Cl a...
Granite and syenite plutons with alkaline affinities ranging in age from 550 to 750 Ma sporadically puncture the Precambrian granulites of the Kerala region. All the bodies are small (20 to 60 sq km), E-W to NW-SE elongated elliptical intrusives with shar...
and apatite for its later exhumation stages. However, at this point of our knowledge of Alpine deformation. A great part of the deformation is also accommodated by flattening of the granite during the greenschist facies metamorphism. The foliation of the Mont Blanc granite is thus not a magmatic one. 3. P-T-t Data [3
The Paleoproterozoic Amritpur Granite Series (AGS) constitutes a cogenetic magmatic suite of S-type granites. The granitic complex shows variation with respect to chemical and mineralogical properties. However, it shows uniformity in the structural state of alkali feldspars. Homogenization experiments on alkali ...
U-Pb dating of zircons (SHRIMP-II) has been performed for the first time for granites, granodiorites, and synplutonic granodiorite and melanodiorite bodies of the Shartash and Shabry massifs in the Middle Urals. The time of the formation of the massifs is 300-306 Ma, which is 25 Ma younger than the previous estimates. The age data obtained are in line with the time of the ...
The origin of granites was once a question solely for petrologists and geochemists. But in recent years a consensus has emerged that recognizes the essential role of deformation in the segregation, transport and emplacement of silica-rich melts in the continental crust. Accepted petrological models are being questioned, either because they require unrealistic rheological ...
The common spatial relationship in convergent orogenic belts between a crustal-scale shear-zone system, high-grade metamorphic rocks, and granites suggests a feedback relation between crustal anatexis and contractional deformation that helps granite extraction and focuses granite ascent. Such a feedback relation has been proposed for ...
The Cambrian Southern Oklahoma Aulacogen (SOA) exposes shallow-seated, A-type sheet granites emplaced on top of layered mafic bodies and under cover of A-type rhyolites, this gabbro-rhyolite boundary being a crustal magma trap. Granites and rhyolites appear to overlap in age, although rhyolites built up first, with the rhyolite pile ...
Four major rock groups are defined in the Southern Complex: the Bell Creek Granite (BCG), the Clotted Granitoids (CGR), the Albite Granite (AGR), and the Migmatite Complex. Metatexites of the Migmatite Complex are the oldest rocks and include paleosome of a metasedimentary and metavolcanic protolith represented by Banded Iron Formation, Banded Amphibolite, ...
The Cambrian orogen that formed in the newly evolving Pacific margin of Gondwana stretched from South Australia and Tasmania (the Delamerian Orogen) across Antarctica (the Ross Orogen) and into southern Africa (Saldanian Orogen). Although the age of initiation of orogenic activity along this belt varied from ~560 Ma in Africa to 514 Ma in Australia, the entire orogenic belt was terminated by a ...
The main stages of the Paleozoic intrusive magmatism in the Urals, 460 420, 415 395, 365 355, 345 330, 320 315, and 290 250 Ma, as well as two virtually amagmatic periods, 375 365 Ma (Frasnian-early Famennian) and 315 300 Ma (Late Carboniferous), are recognized. The Cambrian-Early Ordovician pause predated the onset of igneous activity in the Ural Orogen, while the Early ...
Arc magmas generated at depths near 100 km by dehydration of subducting slabs are olivine-rich melabasalts, but the magmas that reach the surface in mature continental magmatic arcs have an average composition near that of rhyodacite. Depth-varying fractionations and equilibrations profoundly modify the initial magmas. Plate tectonics has operated throughout Proterozoic and ...
Results of detailed field and laboratory studies are reported on the primary distribution of uranium (and thorium and lead) in the radioactive minerals of five radioactive granite bodies in Arizona and California. This distribution was examined in a granite pluton. Granites with uranium concentrations ranging from 4 to 47 ppM, thorium ...
In contrast to I-type granites, which commonly comprise infracrustal and supracrustal sources, S-type granites typically incorporate predominantly supracrustal sources. The initial aim of this study was to identify the sources of three Scottish Caledonian (~460 Ma) S-type granites (Kemnay, Cove and Nigg Bay) by conducting oxygen, U-Pb ...
Peaks in the distribution of U-Pb crystallization ages, and the ages of rocks that reflect new continental crust, are striking features of the continental crust. In the last 1 Gyr there are marked peaks in the zircon crystallization ages, and no analogous peaks of crust formation. In older rocks there appears to be a better match between the peaks of magmatic activity (zircon ...
The 1.4 Ga Varberg-Torpa charnockite-granite intrusion (Varberg, SW Sweden) consists of the magmatic Varberg charnockite (Opx-Cpx-Bt-Amph-Gt-Plg-Kfs-Qtz; accessory FAp, Zrn, Mt, Ilm, Py, Cp, �Po, �Rt), with granitic inlyers, accompanied by in-situ, patchy, fluid-induced, dehydration of local, amphibolite-facies ...
A selected suite of granitic rocks representing both individual differentiation sequences and a broad sampling of granites from North America were analyzed for thorium, uranium, and potassium by gamma -ray spectrometry. In the White Mountain and Oliverian series of New Hampshire both the thorium and uranium contents and the Th/U ratio tend to ...
Eruptions of topaz rhyolites are a distinctive part of the late Cenozoic magmatic history of western North America. As many as 30 different eruptive centers have been identified in the western United States that range in age from 50 to 0.06 Ma. These rhyolite lavas are characteristically enriched in fluorine (0.2 to 2 wt.% in glass) and lithophile trace elements, such as Be, ...
The northern part of the Anatolide-Tauride platform developed at a site of pronounced E-W trending felsic magmatic activity during the late Oligocene-Miocene. These widespread magmatic rocks intruded into the Anatolide-Tauride Block in the south, the Sakarya Continent in the north, and different slices of this collision zone. New geochronological and ...
The 6�3 km Kymi monzogranite stock represents the apical part of an epizonal late-stage pluton that was emplaced within the 1.65 to 1.63 Ga Wiborg rapakivi batholith. The stock has a well-developed zonal structure, from the rim to the center: stockscheider pegmatite, equigranular topaz granite, porphyritic topaz granite. The contact between the two ...
The granites of SW England are characterized by unusually high concentrations of radioactive elements and, related to that, by high rates of heat production and heat flow. They are also relatively permeable due to a high degree of weathering and fracturing. These factors make them to potential sites for post-magmatic hydrothermal convection in response to ...
Gabbro-tonalite-granodiorite-granite (GTGG) plutons productive for gold are suprasubduction intrusive bodies formed at an Andean-type active continental margin 410-380, 365-355, and 320-290 Ma ago. The Devonian plutons are situated in the southeastern marginal continental zone, whereas the Carboniferous plutons occur in the northwestern zone. All GTGG plutons are ...
Hercynian S-type granites from the southeastern Schwarzwald granite series represent cogenetic biotite-and two-mica granites. Oxygen- and hydrogen-isotope data show that hydrothermal alteration invoking isotopically light surface waters resulted in a drastic reduction in ?18O and ? D and pronounced disequilibrium between the minerals. ...
The rare earth phosphate monazite can be a powerful tool for characterizing the timing and spatial extent of fluid infiltration during contact metamorphism. We used an ion microprobe to investigate how wallrock monazite responded to the intrusion of two different granitic plutons, the Cretaceous Birch Creek Pluton (BCP) in the White Mountains of eastern California and the ...
In the Salmon River Arch, a ca. 1,365 Ma rapikivi granite intrudes the Proterozoic Yellow Jacket Formation, which is commonly correlated with the basal Belt-Purcell Supergroup. The contact aureole of the granite contains andalusite and overprints greenschist-facies burial metamorphism in the undeformed sedimentary strata. To the north, the ...
The Baoshan block of the Tethyan Yunnan, southwestern China, is considered as northern part of the Sibumasu microcontinent. Basement of this block that comprises presumably greenschist-facies Neoproterozoic metamorphic rocks is covered by Paleozoic to Mesozoic low-grade metamorphic sedimentary rocks. This study presents zircon ages and Nd-Hf isotopic composition of granites ...
This report is a review of published data bearing on the geology and origin of uranium deposits in granitic, pegmatitic and migmatitic rocks with the aim of assisting in the development of predictive criteria for the search for similar deposits in the U.S. Efforts were concentrated on the so-called ''porphyry'' uranium deposits. Two types of ...
The Podles� granite stock (Czech Republic) is a fractionated, peraluminous, F-, Li- and P-rich, and Sn, W, Nb, Ta-bearing rare-metal granite system. Its magmatic evolution involved processes typical of intrusions related to porphyry type deposits (explosive breccia, comb layers), rare-metal granites ...
The Llano Uplift is a gentle structural dome exposing both island-arc and continental margin blocks emplaced along the southern margin of Laurentia during the Grenville orogeny (locally the Llano orogeny). These ~1370 to 1230 Ma metaigneous and metasedimentary rocks were subsequently intruded by a number of ~1119 to 1070 Ma post-to syntectonic granitic plutons collectively ...
Radiogenic isotopic data from geochemically diverse 1.74-1.50 Ga magmatism in the Eastern Succession, Mount Isa Block (MIB), Australia enables insight into the region's crustal architecture and the nature of mantle activity during episodic orogenesis (1.60-1.50 Ga). These data show that Mesoproterozoic anatectic pegmatites (ca 1.59 Ga) and their host rocks (1.67-1.62 Ga) are ...
Extrusive rhyolites and cogenetic granites of the Wichita province genetically related to the southern Oklahoma aulacogen are entirely sub-alkaline in character. Peralkaline granites occur in the province but are volumetrically minor and have been interpreted by earlier workers as differentiation products of subalkaline magma. The large volumes of ...
Mineralogical indications of high-pressure crystallization of Li-F granites from Russia, Kazakhstan, and Mongolia are discussed. Syngenetic deformation of minerals (protoclasis) in these rocks has been revealed and described for the first time. A possible cause of the effect of high pressure on the solid phase during its crystallization from melt is considered. A progressive ...
The major, minor and trace element chemistry of schorlites from Hercynian granitoids in Northern Portugal indicates that the composition of schorlites varies systematically in comagmatic sequences of granite, aplite and pegmatite. The compositional variation appears to be the result of a magmatic fractionation process. A subsequent recrystallization has ...
The late-Hercynian granites of K�nigshain underwent multistage hydrothermal processes. Extensive high-temperature late-magmatic alteration is, for example, indicated by low Zr/Hf and an REE pattern displaying the tetrad effect. Intensive post-magmatic alteration of the granite occurred along brittle structures. ...
Ion microprobe zircon U Pb ages from metavolcanic and associated granitic rocks of the late Archaean Musoma-Mara Greenstone Belt (MMGB) of northeast Tanzania reveal that the oldest mafic volcanism in the belt occurred at 2676 2669 Ma followed by felsic volcanism at �2668 Ma. The felsic volcanism was coeval with the emplacement of the oldest pulse of massive granitoids that ...
Constraining the timescales for the evolution of planetary bodies in our solar system is essential for a complete understanding of planet-forming processes. However, frequent collisions between planetesimals in the early solar system obscured and destroyed much of the primitive features of the old, first-generation planetary bodies. The presence of differentiated, achondritic clasts in brecciated ...
Central Aegean magmatic belt including the northwestern Anatolia is interpreted in the literature as formed along magmatic arc which has migrated southwardly to its present position. During and after the closure of the Neo-Tethyan Ocean and progressive collision of the Tauride-Anatolide Platform with the Sakarya Continent, widespread ...
The physical and chemical mechanism of ore precipitation in the Yankee Lode tin deposit (Mole Granite, Australia) was quantified by direct trace-element microanalysis of fluid inclusions. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was used to measure element concentrations in a series of fluid inclusions representing the fluid before, during, and ...
This work presents combined structural and geochronological data from Tierra Colorada to Acapulco area that show evidence of five deformational events and four episodes of arc related magmatism during Mesozoic and Cenozoic times. The oldest sequence correspond to metasedimentary units (paragneisses and marbles) metamorphosed in amphibolite facies that are affected by a ...
The Izera Block in the West Sudetes, which is composed of granites, gneisses (and transitional granite-gneisses) and minor mica schists, is one of the largest outcrops of Early Palaeozoic (ca. 500 Ma) metagranitoid rocks in the basement units of the Variscides of Central Europe. The Izera granites show S-type features: ...
The central pluton within the Neoproterozoic Katharina Ring Complex (area of Gebel Mussa, traditionally believed to be the biblical Mt. Sinai) shows a vertical compositional zoning: syenogranite makes up the bulk of the pluton and grades upwards to alkali-feldspar granites. The latters form two horizontal subzones, an albite alkali feldspar (Ab Afs) ...
Discussions of Basin and Range evolution in the southern Rocky Mountains and Great Basin highlight the role of magmatism in crustal extension, where many temporal and spatial relationships between magmatism and extension have been established. Two types of extensional faulting of similar age affected northwest Montana and northern Idaho: listric normal ...
Among the different rock units in the Gabal Ribdab area, the two-mica leucogranite and muscovite pegmatitic granite are the most favourable host rocks for uranium and thorium mineralization. The muscovite pegmatitic granite shows evidence of post-magmatic alteration, e.g. Na- and K-metasomatism, whereas the two-mica leucogranite could ...
Radioactivity of noncontemporaneous magmatic, metamorphic, and ore formations was determined over a wide area of the Soviet Northeast from 1500 analyses of uranium and 800 analyses of thorium (x-ray spectral and luminescence analyses). Leucocratic and alaskitic potassium granites of the culminating phases of late Mesozoic granitoid assemblages have ...
The local heterogeneity of K, Rb, Ti, Zr, P, Sr, and Ba was determined by x-ray fluorescence analysis as a first step in investigations of the regional heterogeneity of a whole granite body of larger extent. The first granite of this series is the Malsburg-Granite in the southwest of the Black Forest. The analytical results ...
The role of fluids during Archaean intra-crustal magmatism has been investigated via integrated SHRIMP U-Pb, ?18O and LA-MC-ICPMS 176Hf isotopic zircon analysis. Six rock samples studied are all from the Nuuk region (southern West Greenland) including two ~3.69 Ga granitic and trondhjemitic gneisses, a 3.64 Ga granitic augen gneiss, a ...
Lithologically, the rock types in the Gabal El Fereyid area are dominantly granites with minor amounts of pegmatites. The granites range in composition from tonalite to granite-adamallite with minor acidic dikes, quartz and pegmatite veins. The granite-adamallite is peraluminous and formed as a result of partial ...
Granites classified into four categories based solely on tectonics of occurrence and associated rock types also have compositional characteristics that are consistent within groups and different among groups. Orogenically related granites include late-orogenic varieties (LO) associated with calc-alkaline batholiths, and post-orogenic varieties (PO), which ...
A post-tectonic plutonic array of felsic I-type granites crops out in the western Hercynian Iberian Belt. Isotope (Sr, Nd, Pb) data favour the absence of an important input of juvenile magmas in late- to post- tectonic Hercynian felsic magmatism in western Iberia, but suggest a reworking of different crustal protoliths, including oceanic metabasic rocks ...
Whole-rock samples of three oceanic basalts, one diabase, and four granites from northeastern North America, and feldspar and mica mineral concentrates from three of the granites have been analyzed for La, Eu, and Dy by means of neutron activation. By plotting on a logartthmic scale the concentration versus atomic number of each rare-earth element ...
A number of plutons of charnockitic and granitic rocks have been revealed in the West Lithuanian Granulite Domain in the course of the recent geological mapping. The largest, Kur�iai (Curonian), batholith has been identified by gravity and magnetic anomalies and drill cores of 86 wells. Intrusions are composed of rocks of intermediate to felsic composition systematically ...
The geological survey of the Florianopolis Sheet (SG.22-Z-D-V) identified and characterized a calc-alkacic multi-intrusive and polydiapiric suite that occurs as a granitic batholite roughly concentric in texture and composition. This co-magmatic plutonic ...
.K., Bouchez, J.L., 1996. The Pan-African Toro Com- plex (northern Nigeria): magmatic interactions-slip emplacement of the Pan-African granite of Solli Hills, northern Nigeria. Tectonics 14, 1205�1219. Ferre�, E solid=melt ratio, crystallized in situ in a non-dynamic setting and were not related to a major orogeny
. Monazites have been extracted from crushed granite samples using dense liquors and handpicked under and method described by Cocherie and Albarede 2001. Mineralogical characterization of monazite grains has, the existence of a late thermal event that can reset Ar within mica is strongly suspected. Monazite dating All
Contents: Special Issue for Overseas Geology and Mineral Resources (I)--Calc-alkaline Magmatism and Related Mineralization in Chile; Plutonic Rocks of North-Central Chile; Late paleozoic Granitic Rocks from Northern Chile; Geochemical Studies of Upper Cen...
Basing on the field investigations and previous geological results, we do a synthesis research on four granite bodies of the South China block. In the field outcrop, the muscovite-sillimanite-bearing granites are gradually changed from wall rock to gneissic granite. Several residual blocks of sandy slate are found in the margin of ...
A model for trondhjemite genesis is proposed where granite is transformed to trondhjemite via infiltration by a Na-rich metamorphic fluid. The Rockford Granite of the Northern Alabama Piedmont serves as the case example for this process and is characterized as a synmetamorphic, peraluminous trondhjemite-granite suite. The major process ...
Our aim here is to better understand the age and tectonic history of crystalline basement units in the Sakarya Zone of N Turkey, north of the Neotethyan ?zmir-Ankara-Erzincan Suture Zone, utilising field, petrographic and ion probe dating, the latter carried out at the University of Edinburgh. One of the largest basement units, Central Sakarya, is dominated by paragneisses and schists that are ...
The 750-Ma Seychelles granites have whole-rock ?18O values that range from -1.2 to +7.5�. Differences in ?18O values between quartz, feldspar and whole-rock for samples that have a range of ?18O values suggest that these minerals are in magmatic equilibrium, and that the whole-rock ?18O values were little affected by post-crystallization interaction with ...
The late-Eocene-early Oligocene Zahedan granitic rocks are the most important intrusive rocks in the Nehbandan-Khash tectonic zone located in the east of Iran. This zone is composed of oceanic crust rocks such as flysch facies, mafic and ultramafic rocks that are intruded by the Zahedan granitic rocks and extend for a long distant in a narrow zone almost ...
Textures and compositional relationships associated with dark-colored, fine-grained enclaves in the Cadillac Mountain and Somesville granites, Mount Desert Island, Maine, preserve abundant evidence for contamination of host granitic magmas by enclave liquids. Fine-grained enclaves, which apparently represent chilled magmatic droplets, ...
The Betic-Rif orogen forms the western termination of the Alpine orogenic system in the Mediterranean region. The precise timing, structural evolution, and distribution of high-grade metamorphic units (Alpine versus pre-Alpine) in the inner zones of the orogen (Alboran Domain) remain controversial issues. In this paper we report occurrence of distinct generations of peraluminous ...
The tectonic boundary between the Grenville-age Oaxacan and Paleozoic Acatl�n crystalline complexes in southern Mexico, named the Caltepec fault zone (CFZ), is characterized for the first time as a dextral transpressional, NNW trending and ENE dipping ductile fault zone of Early Permian age. The complexes are welded by a syntectonic magmatic epidote-bearing ...
In the granitic rocks of the Western Carpathians, xenotime-(Y) occurs both as a late-stage magmatic mineral, and as a secondary post-magmatic phase. Magmatic xenotime occurs with monazite and displays minor compositional zonation involving Si, Th and U. The source of elements for the formation of secondary ...
The Bracks Rhyolite, Star Mountain Formation, and Crossen Trachyte are related, voluminous, high-temperature ([ge]900 C) silicic lavas that constitute an abrupt, major eruptive event in Trans-Pecos Texas. They were emplaced rapidly at 36.8 Ma, at the onset of the main phase of subduction-related volcanism and immediately preceding a major basalt outpouring. Individual flows are as much as 55 km ...
The Deh-Salm metamorphic Complex (DMC) of the Lut block in East Iran consists of metapelites, amphibolites, marbles, and metasandstones intruded by granite and pegmatites. U-Pb dating of zircon, monazite, xenotime, and titanite by ID-TIMS show that the granitic rocks were emplaced at 166-163 Ma, confirming that the high temperature metamorphism was ...
Many geologists believe that uraniferous hydrothermal solutions arise from deep-seated granite magmas in late stages of development. Smirnov considers this a paragenetic relationship (indirect or fraternal), making postmagmatic deposits and magmatic bodies derivatives from a common source. This viewpoint has not yet received physicochemical confirmation, ...
The lattice-preferred orientation (LPOs) of two late-Variscan granitoids, the Meissen monzonite and the Podles� dyke granite, were determined from high-resolution time-of-flight neutron diffraction patterns gained at the diffractometer SKAT in Dubna, Russia. The results demonstrate that the method is suitable for the LPO analysis of polyphase, relatively coarse-grained ...
The Mount Genis granite is one of the post-tectonic intrusives emplaced late in the magmatic history of the Hercynian batholith in Sardinia. Devitrified silicate melt inclusions are present in some (magmatic) rock-forming and miarolitic quartz. These magmatic remnants show initial melting at 680- 720�C. ...
Detailed studies of North American Cordilleran sheeted plutons (Miller and Paterson, 2001; Mahan et al., 2003; Manduca et al., 1993) reveal that some have predominantly sub-vertical geometries, indicating construction within fundamentally vertical boundary zones in mid-crustal terrains. In contrast, the Bighorn sheeted complex of the eastern Transverse Ranges in southern California preserves ...
The Puutsaari intrusion is a potassium-rich magmatic complex in the eastern part of the Svecofennian domain close to the Archaean border. The intrusion is generally undeformed in contrast to 1880-1875 Ma-old country rock tonalitic migmatites and diatectites. The main rock types are (1) mafic rocks of a gabbro-norite - diorite quartz monzodiorite series, (2) quartz diorite ...
Mount Kinabalu is a granite body in north Borneo that intrudes rocks deformed in the Early Miocene Sabah Orogeny following subduction of the South China continental margin beneath the north Borneo margin. Kinabalu is the highest mountain in SE Asia at 4100m and ice action during Pleistocene glaciations has resulted in excellent exposure of the summit area. The ...
The EPS-1 drilling occurs within the Upper Rhine Graben and penetrates Variscan granites from 1420 to 2200 m depth. According to studies of Traineau et al. (1991) two main hydrothermal alteration stages were determined. An early propyllitic and pervasive alteration took place during cooling and uplift history of the pluton. The multiphase evolution of the Cenozoic rift was ...
Penang Island represents the northwestern extension of the western magmatic belt of Peninsular Malaysia. Thirty-one samples of highly evolved biotite-and biotite-muscovite granites were used in an integrated study to unravel the complex magmatic, tectonic and cooling histories of these rocks. Highly distorted Rb?Sr whole-rock age ...
Inherited zircons from S-type granites provide exceptionally good insight into the isotopic heterogeneity of their sources. Zircons from four samples (one granite, two granodiorites, one granodioritic enclave) of Pan-African S-type granite of the Cape Granite Suite (c. 540 Ma) have been the subject of a laser ...
We present geochronological data for late-Variscan magmatism in the Lausitz Block of the Saxo-Thuringian Zone, Germany. The Th-U-total Pb age of uraninite and the Re-Os age of molybdenite from the composite biotite-monzogranite pluton of K�nigshain overlap at the 2? confidence limit: 328.6 � 1.9 Ma (uraninite), and 327.0 � 1.3 Ma and 327.6 � 1.3 Ma (molybdenite), ...
The heterogeneity of the continental crust has a first order control on the dynamics of plate tectonic processes and the compositions of the Earth in both time and space. Heterogeneity can be characterized at a variety of scales and in a multitude of tectonic environments, but it is the links between seemingly disparate tectonic settings and crustal levels that are critical in understanding ...
The country rock in southern Finland formed mainly during the Svecofennian orogeny ca. 1.9 Ga ago. The middle and lower crust was partially melted 1.83 Ga ago due to crustal thickening and subsequent extension. During this event, S-type migmatites and granites were formed along a 100�500 km zone. This Late Svecofennian Granite Migmatite zone (LSGM zone) ...
The Dalat zone in southern Vietnam comprises a Cretaceous Andean-type magmatic arc with voluminous granitoids and contemporary volcanic rocks. On the basis of petrographical and mineralogical studies, the granitoids were subdivided into three suites: Dinhquan, Deoca and Cana. Rocks of the Dinhquan suite are hornblende-biotite diorites, granodiorites and minor ...
Pan-African basement rocks and a Paleozoic cover series, which were intruded by the protoliths of leucocratic orthogneisses, have been recognized in the Menderes Massif, located in the western part of the Alpine orogenic belt of Turkey. This geochemical and geochronological study focuses on the evolution of the Menderes Massif at the end of Paleozoic time. Geochemical data suggest that the ...
The Modoc fault zone is a prominent zone of simple shear that has been mapped for 250 km from near Columbia, SC to the Ocmulgee River, in central GA. The steeply northwest-dipping fault zone is up to 5 km wide and contains variably mylonitic paragneiss and synkinematic sheets of mylonitic granite. Rotated tension gashes, reverse-slip-slip-crenulations, and asymmetric ...
The Kalguty ore-magmatic system (OMS) contains economic greisen and vein rare-metal-tungsten-molybdenum mineralization. The data on U-Pb zircon (SHRIMP II) age of nine samples of igneous rocks from the Kalguty OMS are accompanied by chemical, ICP-MS, and ICP-AES analyses of the main rock varieties. Porphyritic biotite granite of the main phase of the ...
The central-eastern part of the Sierra de Velasco (Sierras Pampeanas, NW Argentina) is formed by the large Huaco (40 � 30 km) and Sanagasta (25 � 15 km) granite massifs and the small La Chinchilla stock (2 � 2 km). The larger granites intrude into Ordovician metagranitoids and crosscut Devonian (?) mylonitic shear zones, whereas the small stock ...
Many orogens on Earth, which are developed in long-lived (>300 Ma) mobile belts, have undergone multiple orogenesis. Hyndman et al. (2005) proposed that these mobile belts had been evolved from backarcs, where extensional rifting had resulted in the thinning of lithosphere and thermal convection, which in turn led to the heating of backarcs. When continents collided, deformation took place ...
Assessment of geological, geochemical and isotopic data indicates that a significant subgroup of volcanic-hosted massive sulphide (VHMS) deposits has a major or dominant magmatic-hydrothermal source of ore fluids and metals. This group, which is typically characterised by high Cu and Au grades, includes deposits such as those in the Neoarchean Doyon-Bousquet-LaRonde and ...
The Idaho batholith/Challis magmatic system is characterized by a history of magmatism roughly 75 million years in length, marked by major shifts in the locus and composition of magma in an evolving tectonic setting, making it a key but poorly understood element in the Cordilleran batholith system of western North America. Integration of new in situ U-Pb ...
The succession of magmatic events associated with development of the Early Carboniferous-Early Permian marginal continental magmatic belt of southern Mongolia is studied. In the belt structure there are defined the successive rock complexes: the older one represented by differentiated basalt-andesite-rhyodacite series and younger bimodal complex of ...
The Chiapas Massif (CM) is located in SE Mexico and extends over an area of more than 20,000 Km2 parallel to the Pacific coast between the Isthmus of Tehuantepec and the Guatemalan border. It constitutes the largest batholitic complex in Mexico and belongs to the Maya Block. The CM is predominantly formed by igneous, metaigneous and metasedimentary rocks. In the central CM several ...
The Danish island of Bornholm is located at the southwestern margin of the Fennoscandian Shield, and features exposed Precambrian basement in its northern and central parts. In this paper, we present new U-Pb zircon and titanite ages for granites and orthogneisses from 13 different localities on Bornholm. The crystallization ages of the protolith rocks all fall within the ...
East Antarctica figures prominently as a central cratonic piece in reconstructions of the Neoproterozoic supercontinent Rodinia, yet these fits variously position East Antarctica next to (so-called SWEAT fit), or distant from, the western margin of Laurentia. Paleomagnetic poles are lacking for East Antarctica during the time period between assembly at about 1.3-1.1 Ga and subsequent breakup by ...
Bulk ? 34Srock values, sulfur contents, and magnetic susceptibility were determined for 12 gold-related granitoid intrusions in southwestern New Brunswick, the Canadian Appalachians. The sulfur isotope compositions of sulfide minerals in some of the granitoid samples were also analyzed. This new dataset was used to characterize two distinctive groups of granitoids: (1) a Late Devonian ...
In this study, formation of titanite, in Carboniferous I-type granites/granitoids from the Tribe? Mountains (Slovakia), and its subsequent alteration products are described. Titanite occurs in early magmatic differentiates of I-type granites/granitoids. Calculation of model mineral equilibria in the system K2O CaO FeO Al2O3 TiO2 SiO2 ...
The modern territory of the Magadan region is area of the two types of geodynamic environments (collisional and subductional), which defined the specifity of granitoid magmatism and metallogeny. Yana-Kolyma I- and S-type granitoids of the ilmenite series: diorite-granodiorite and granite-leucogranite magmatic suites (155-135 Ma) was ...
The interaction of columbite and uraninite with a fluid-magma system consisting of a melt of Li-F-granite and fluoride fluid at 750�C and P = 2300 bar causes the formation of zonal pyrochlores being considerably different in uranium and fluorine contents. Fluorine-rich pyrochlores (to 7-12 at %) preserve the Nb/U ratio of the initial columbite (15-30). Uranium-bearing ...
The moon is a much more diverse and heterogeneous body than sometimes realized, and need not be considered merely a source of common elements. Possible anhydrous magmatic ore-forming processes include cumulate deposits (of Cr and other metals), and formation of immiscible liquids (silicate-silicate, silicate-oxide, silicate-sulfide). Analogs of carbonatites may occur. Rare, ...
Studies of the anorthositic-gabbroic rocks of the Layered Series of the Wichita province, Oklahoma, establish petrologic constraints that suggest the body is an eroded stratiform gabbro complex, originally several kilometres thick, exposed at its approximate midsection. These rocks appear to be genetically unrelated to most of the other igneous rocks of the province. Uplift and erosional removal ...
The methods and results are reported of a spectrometric study, carried out with the SP-3 instrument in Pre-Cambrian fornnations in the northwest ranges of Kola Peninsula for clarification of the radiochemical characteristics of the rocks of the region and of the distribution characteristics of radioactive elements in Cu-Ni mineralizations. It was established that the content of ...
The Cuffytown Creek pluton is a leucocratic alkali feldspar granite with (F + Mn)-rich biotite, muscovite, garnet, and fluorite as varietal minerals. Bt [plus minus] Ms is preserved as inclusion assemblages in quartz; Bt + Ms [plus minus] Grt and Ms + Grt are matrix assemblages. The inclusion assemblages are interpreted as early magmetic, and the matrix assemblages as late ...
The Sierra Ballena Shear Zone (SBSZ) is part of a high-strain transcurrent system that divides the Neoproterozoic Dom Feliciano Belt of South America into two different domains. The basement on both sides of the SBSZ shows a deformation stage preceding that of the transcurrent deformation recognized as a high temperature mylonitic foliation associated with migmatization. Grain boundary migration ...
The Mucaja� AMCG complex forms the southeasternmost termination of the ca. 900 km Mesoproterozoic rapakivi granite belt in the northern part of the Amazonian craton. The rock types of the complex comprise massif-type anorthosite and quartz-fayalite mangerite to -syenite (FMS) partially surrounded by a two-phase, dominantly pyterlitic, rapakivi granite ...
In this study, the Karaabalar magmatik rocks exposed between the town of Karaabalar and the town of Caglay?k (K?rklareli) was investigated to determine its petrological and geochemical characteristics. In the study area, the basement lithologies are represented by the Paleozoic Korukoy formation that mainly consists of granitic gneisses, granite with ...
In the southern part of the Hrub� Jesen�k Mts. (Silesicum, Bohemian Massif) granitic orthogneisses and quartz-feldspars mylonites occur that were variously deformed, metamorphosed and imbricated with the overlaying Devonian volcano-sedimentary complex during the Variscan orogeny. Based on combined mapping, petrologic and geochemical studies, three main rock groups are ...
The Grunehogna Craton (GC, East Antarctica) is interpreted as part of the Archean Kaapvaal Craton of southern Africa prior to Gondwana breakup. The basement of the GC is only exposed within a small area comprising the dominantly leucocratic Annandagstoppane (ADT) granite. The granite (and hence the craton) has been dated previously only by Rb-Sr and Pb-Pb ...
The 57 m.y. Middle Fork Plutonic Complex (MFPC) intrudes Paleozoic metasedimentary rocks south of the Farewell Fault zone in the north-central Alaska Range. Though spatially related to the late Cretaceous - Early Tertiary subduction-related Alaska Range batholith, MFPC is more characteristic of an extensional or anorogenic setting. A swarm of basalt, hawaiite and rhyolite dikes east of the complex ...
The India-Asia collision zone in the Transhimalayan Indus and Shyok Tectonic Belts (STB) of Ladakh, NW India is characterized by two major granitic batholiths. The northern, Karakoram Granitic batholith and the southern, Ladakh Granitic batholith are separated by thrust-bound belts of ophiolite, flysch and calc-alkaline volcanics of ...
The Avalonian Terrace south of Boston is largely underlain by the Dedham Plutonic suite dated at 630 +/[minus]15 Ma. In an area located between the Proterozoic Z Boston Basin and the Carboniferous Narragansett Basin, the Dedham plutonic series is intruded by late Avalonian suites of Westwood Granite and the newly recognized intrusives of the Cohasset Pluton. The Cohasset ...
Two texturally and chemically distinct types of tourmaline are found inside peraluminous granites of the Moslava?ka Gora, Croatia: nodular tourmaline in the two-mica granite and disseminated tourmaline in the cross-cutting leucogranite dykes. Both tourmaline types belong to alkali tourmaline group, nodular tourmaline being dravite to schorl and ...
The Piedade Granite (approximately 600 Ma) was emplaced shortly after the main phase of granite magmatism in the Agudos Grandes batholith, Apia�-Guaxup� Terrane, SE Brazil. Its main units are: mafic mineral-rich porphyritic granites forming the border (peraluminous muscovite-biotite granodiorite-monzogranite ...
Petrography of the Pendales Formation at Arroyo Henequ�n (Atlantico) revealed that conglomeratic lithoarenites and polymictic conglomerates contain detrital quartz, potassium feldspars, plagioclase, serpentinite, chert, epidote, tourmaline, actinolite and volcanic rock fragments. This composition indicates provenance from two sources, one mainly composed of ocean floor materials, and another ...
The Archaean Kolmozero-Voron�ya greenstone belt is one of the most ancient geological structures of the Kola Peninsula. It is located between Upper Archaean terrains: Murmansk, Central Kola and Keivy. Within the Kolmozero-Voron'ya greenstone belt there are rare metal (Li, Cs with accessory Nb, Ta, and Be), Cu, Mo, and Au deposits. All rocks were metamorphosed under amphibolite facies conditions ...
Magmatic rocks of the Pikan and Un�ya massifs situated in eastern segment of the Mongolian-Okhotsk foldbelt are studied using isotopic-geochronological (U-Pb zircon dating) and geochemical methods. Two rock complexes different in age are recognized in the Pikan massif: the high-Al gabbro-tonalite association of the Middle Ordovician (468 � Ma) and ...
The Neoproterozoic Ara�ua� belt of eastern Brazil records the closure of a Red Sea-type basin between the S�o Francisco and Congo cratons of West Gondwana, and is part of the Brasiliano (Pan-African) orogenic system. In its southern part this basin contained oceanic crust, so that closure involved subduction and arc magmatism prior to continental collision. In its ...
During the last decade, studies on magmatic fabrics on different scale have been made for analyzing kinematics of melt emplacement and deformation as well as cooling histories of magmatic bodies and their host rocks (Brown 2001). The problem arises for comparing data from structural analysis in thin-sections and fabrics in outcrop scale. ...
Two orogenic cycles, both with different evolution, are developed in the western margin of the South American continent in northern Argentina and Chile: the Paleozoic �Hercynic� cycle and the Meso-Cenozoic �Andean� cycle. The Hercynic cycle. A wide marine basin extending westward of the Cordillera Oriental which developed in Cambrian-Ordovician times marks the beginning of this cycle. In ...
Large igneous provinces (LIPs) related to ascending of mantle superplumes have played important role in tectonomagmatic processes on the Earth. However, it is not clear yet how structured their magmatic systems and how they operate. Significant information for this can be got from geological-petrological data on different LIPs. The main features of ...
The calc-alcaline granitoids of the Hercynian Corsica Batholith show a large-scale magmatic flow pattern, outlined by the alignment of large (mm-cm) euhedral feldspar crystals. The trend of the steep magmatic foliation is generally N-S in the northern part of the island, swings to approximately E-W orientation in the central part of the Batholith and back ...
In the Variscan Western Tatra granites hybridization phenomena such as mixing and mingling can be observed at the contact of mafic precursors of dioritic composition and more felsic granitic host rocks. The textural evidence of hybridization include: plagioclase-K-feldspar-sphene ocelli, hornblende- and biotite-rimmed quartz ocelli, plagioclase with ...
The hydrothermal Mo-U deposits of the Strel�tsovka ore field, unique in reserves, are localized in the Late Mesozoic caldera of the same name. The consideration of geochemical processes that controlled uranium transfer by ore-bearing fluids and its precipitation in orebodies has shown that a nonstationary temperature distribution could have exerted a substantial effect on ore formation. The ...
Triassic magmatism in the southwest US Cordillera forms a semicontinuous magmatic arc extending from northwestern Nevada to southeastern California. Quartz monzodioritic and quartz monzonitic rocks and associated diorites and granites are widespread in southeastern California, and the authors suggest that these rocks represent exposure ...
Traiassic magmatism in the southwest U.S. Cordillera form a semicontinuous magmatic arc extending from northwestern Nevada to southeastern California. Quartz monzodioritic and quartz monzonitic rocks and associated diorites and granites are widespread in southeastern California, and we suggest that these rocks represent exposure of a ...
There are the Mesozoic large-scale magmatism and the mineralization in South China. As amajor part of East Asian, South China continent is an extremely complex region, involving the multi-stages of the Mesozoic tectono-magmatic activity. Therefore, various patterns have been proposed in the recent 20 years. There are various isotopic ages for four ...
Detailed petrographic and mineralogic investigations of an albite-lepidolite granite at Echassi�res (Massif Central, France; scientific deep drill program) shows the existence of hydrothermal stages which are closely related to the magmatic and structural history. According to fluid inclusion data, K-Ar datations and 18O/16O-D/H compositions of secondary ...
Mo mineralization within the Galway Granite at Mace Head and Murvey, Connemara, western Ireland, has many features of classic porphyry Mo deposits including a chemically evolved I-type granite host, associated K- and Si-rich alteration, quartz vein(Mace Head) and granite-hosted (Murvey) molybdenite, chalcopyrite, pyrite and magnetite ...
The Fosdick Mountains in Marie Byrd Land, West Antarctica comprise a migmatite dome 80x15km composed of paragneiss, orthogneiss and associated granites. The dome represents exposed middle-crust that experienced a polymetamorphic evolution associated with the active margin of Gondwana during the Devonian-Carboniferous and the Cretaceous. Research to date has focused on the ...
The Maya Block can be defined as Guatemala north of the Motagua transform fault, Belize, and part of southern Mexico. The absence of radiometric ages has hindered an understanding of the geologic evolution of the Maya Block and its connections with adjacent blocks in North America, South America and the Caribbean. We present an exploratory study of SHRIMP U/Pb ages from zircons collected in ...
The Malayer area is located in the NW-SE aligned Sanandaj-Sirjan metamorphic belt, western Iran and consists mainly of Mesozoic schists so-called Hamadan Phyllites, Jurassic to Tertiary intrusive rocks and related contact metamorphic aureoles, aplites and pegmatites. The Sanandj-Sirjan Zone is produced by oblique collisional event between Arabian plate and Central Iran microcontinent. Highest ...
Papers are presented on such topics as hypotheses concerning the evolution of the earth crust in the early Precambrian (EP); the EP tectonics and stratigraphy of the Ukrainian Shield; the main EP tectonic features of the Aldan Shield; the foundation tectonics of the Russian and Siberian plates; gray-gneiss evolution regions; and the early Proterozoic stage of crustal evolution. Attention is also ...
New U-Pb ages for granites from the New Brunswick part of the Canadian Appalachians indicate that >90% of the undeformed felsic plutons are Silurian and not Devonian as previously thought. Silurian igneous and sedimentary assemblages were recently recognized throughout the Canadian Appalachians, although the petrogenetic types of magmas as well as the grades of metamorphism ...
Data are presented on a method of concentrating assays of erapted rocks for determining rare and dispersed elements contained in them. The concentration is effected by removing silicic acid, the content of which in the granites is as high as 80%. Preliminary results indicate that this method considerably facilitates the determination of Cr, V, Cu, Pb, Sn, Zn, Ni, Be, ...
Piston-cylinder experiments in the granite system demonstrate that a variety of isotopically distinct melts can arise from progressive melting of a single source. The relation between the isotopic composition of Sr and the stoichiometry of the observed melting reactions suggests that isotopic signatures of anatectic magmas can be used to infer melting reactions in natural ...
A Rb/Sr isochron of 2154 +- 20 M.y., with Ro = 0,705 +- (MSWD=2,85) has been obtained for the Itaberaba and Pedra d'Agua granites, located on the northern limit between the Archean Jequie cratonic nucleous and the Early Proterozoic Salvador - Curaca mobil...
The St. Francois Mountains constitute the exposed portion of an extensive Precambrian terrane of anorgenic, granitic ring complexes identified on the basis of drillhole data and aeromagnetic maps. The terrane is characterized by the predominance of alkaline-silicic over mafic rocks, and trachytic intermediate rocks. The distinctive ore deposits are (1) ...
The Northern Vosges is the rare area where the earliest Carboniferous magnetizations have escaped middle-late Carboniferous overprints. The magmatic arc intruding shallow Armorican (Saxothuringian) crust is the key domain where the effects of subsequent tectonic evolution can be observed. Diorites, tonalites and granites of the northern Vosges ...
This work brings into focus different metal associations (Fe and Mo-Cu) characteristic for the Karacaali Magmatic Complex (KMC), in Central Anatolia, Turkey. The Mo-Cu mineralization is widespread hosted in rhyolitic-rhyodacitic/granidoid rocks or is related to N-S striking vertical quartz-calcite veins. The Fe mineralization, on the other hand, is hosted in gabbroic/basaltic ...
Macro- and microstructures of syntectonic granitoids provide numerous information about (i) crystallization, deformation and rheology history of these rocks, (ii) development of fabric anisotropy and heterogeneity during flow processes, and (iii) relationships between local and regional kinematics. The Piquiri Syenite Massif (611+-3 Ma) is part of the post-collisional ...
Precambrian Laurentia and Mesozoic Gondwana both rifted along geometric patterns that closely approximate truncated-icosahedral tessellations of the lithosphere. These large-scale, quasi-hexagonal rift patterns manifest a least-work configuration. For both Laurentia and Gondwana, continental rifting coincided with drift stagnation, and may have been driven by lithospheric extension above an ...
