NASA Astrophysics Data System (ADS)
Aydin, Isil; Fidan, Celal; Kavak, Orhan; Erek, Figen; Aydin, Firat
2017-12-01
Asphaltite is one of the naturally occurring black, solid bitumen’s, which are soluble at heating in carbon disulphide band fuse. Asphaltite is also a solidified hydro carbon compound derived from petroleum [1]. According to the World Energy Council, Turkish National Committee (1998), the total reserve of the asphaltic substances that are found in south eastern Turkey is about 82 million tons, with Silopi and Sirnak reserves to get her comprising the major part of the Asphaltite deposits. Selenium and Nickel are very important elements both environmental and health. Selenium plays an important role in the formation of the enzyme antioxidant effect in the cell. The need for Selenium increases in situations such as pregnancy, menopause, grow than development, air pollution. Nickel is used for preventing iron-poor blood, increasing iron absorption, and treating weak bones. In this study, asphaltites were taken from Milli vein from Sirnak deposit in SE Anatolia of Turkey. A total of 6.500.000 tons of Asphaltite reserves have been identified as asphaltites in Milli (Sirnak). The sample preparation method was developed in Asphaltite by spectroanalytical techniques, wet acid digestion. MW-AD followed by ICP-OES were used for the determination of Selenium and Nickel in Asphaltite. Proximate analysis of Asphaltite fly ash samples was made. It also, Selenium and Nickel element analysis in Asphaltite were made.
Wyant, Donald G.
1953-01-01
Deposits of uraniferous hydrocarbons are associated with carnotite in the Shinarump conglomerate of Triassic age at Shinarump Mesa and adjacent areas of the Temple Mountain district in the San Rafael Swell of Emery County, Utah. The irregular ore bodies of carnotite-bearing sandstone are genetically related to lenticular uraniferous ore bodies containing disseminated asphaltitic and humic hydrocarbon in permeable sandstones and were localized indirectly by sedimentary controls. Nearly non-uraniferous bitumen commonly permeates the sandstones in the Shinarump conglomerate and the underlying Moekopi formation in the area. The ore deposits at Temple Mountain have been altered locally by hydrothermal solutions, and in other deposits throughout the area carnotite has been transported by ground and surface water. Uraniferous asphaltite is thought to be the non-volatile residue of an original weakly uraniferous crude oil that migrated into the San Rafael anticline; the ore metals concentrated in the asphaltite as the oil was devolatilized and polymerized. Carnotite is thought to have formed from the asphaltite by ground water leaching. It is concluded that additional study of the genesis of the asphaltitic uranium ores in the San Rafael Swell, of the processes by which the hydrocarbons interact and are modified (such as heat, polymerization, and hydrogenation under the influence of alpha-ray bombardment), of petroleum source beds, and of volcanic intrusive rocks of Tertiary age are of fundamental importance in the continuing study of the uranium deposits on the Colorado Plateau.
Study of Usage Areas of Clay Samples of Asphaltite Quarries in Sirnak, Turkey
NASA Astrophysics Data System (ADS)
Bilgin, Oyku
2017-12-01
The asphaltite of Sirnak, Turkey are in the form of 12 veins and their total reserves are anticipated to be approximately 200 million tons in a field of 25.000 hectares. The asphaltites at the Sirnak region are in the form of fault and crack fillings and take place together with clay minerals at their side rock. The main raw materials used in the production of cement are limestone, clay and marn known as sedimentary rocks. Limestone for CaO and clay minerals for SiO2, Al2O3, and Fe2O3, which are the main compounds of clinker production, are the main raw materials. Other materials containing these four oxides like marn are also used as cement raw material. Conformity levels of the raw materials to be used in cement production vary according to their chemical compounds. The rocks to be used as clay mineral are evaluated by taking the rate of silicate and alumina into consideration. The soils suitable for brick-tile productions are named as sandy clay. Their difference from the ceramic clays is that they are richer in terms of iron, silica and carbonate. These soils are also known under the names such as clay, arid, alluvium, silt, loam and argil. Inside these soils, minerals such as quartz, montmorillonite, kaolinite, calcite, limonite, hidromika, sericite, illite, and chlorite are available. Some parts of the soils consist of clays in amorphous structure. Limestone parts, gypsums, organic substances and bulky rock residuals spoil the quality. The soils suitable for brick production may not be suitable for tile production. In this case, their sandy soils should be mixed up with the clays with fine granule structure which is high in plasticity. During asphaltite mining in Sirnak region, clays forming side rock are gathered at dump sites. In this study; SQX analyses of the clay samples taken from Avgamasya, Seridahli and Segürük asphaltite veins run in Sirnak region are carried out and their usage areas are searched.
NASA Astrophysics Data System (ADS)
Kovaleva, O.
2009-04-01
Solid hydrocarbons (bitumens)-typical specimens of natural organic minerals-are one of the most essential objects of petroleum geology and at the same time-one of the least investigated objects of organic mineralogy. Moreover they can be treated as admissible analogs of meteorite carbonaceous materials. According to terrestrial analog of meteoritic organic matter it's possible to estimate the chemical structure of extraterrestrial matter. Further investigation of impact force and radiation influence on the bitumen chemical structure change will make it possible to connect them with extraterrestrial organic matter. This work represents the research of impact influence on the processes of transformation and structuring of asphaltite and changes in the molecular structure of solid bitumens constituting the carbonization series (asphaltite--kerite--anthraxolite), which were subjected to the impact of high radiation doses (10 and 100 Mrad) by infrared spectroscopy (IRS). In percussion experiments peak pressure varied from 10 to 63.4 GPa; temperature - from the first tens degrees to several hundreds degrees Celsius. The radiation experiment was performed in the Arzamas-16 Federal Nuclear Center in line with conditions described in [1]. Asphaltite, which sustained shock load from 17.3 to 23 GPa, didn't undergo considerable changes in its element composition. Though their IR-spectra differ from the spectrum of initial asphaltite by heightened intensity of absorption bands of aromatic groups, as well as by insignificant rise of heterogroups and condensed structures oscillation strength. At the same time the intensity of aliphatic (СН2 and СН3) groups absorption hasn't changed. Probably there've just been the carbon and hydrogen atomic rearrangement. However, shock load up to 26.7 GPa leads to asphaltite transformation into the albertite. There've been observed the intensity decrease of aliphatic groups on its IR-spectrum. Under growth of shock load up to 60 GPa bitumen has lost essential part of aliphatic, hetero-groups. Relative intensity of absorption bands of aromatic groups has dramatically increased. By nature and intensity of absorption bands this spectrum looks more similar to the impsonite/lower anthraxolite. A pressure of 60 GPa has lead to further matter carbonization. IR-spectra of these specimens have weak absorption bands and are mostly presented by aromatic structures. They've become similar to middle/high anthraxolite. A pressure of more than 60 GPa (with kamacite) has resulted in dramatic coalification of the material. The details have completely vanished in their spectra and they've grown similar with graphite. It should be noted that these specimens have been taken from the lower parts of ampoules. At the same time it has been established that IR-spectra of specimens from the upper parts are indicative of less coalification. Their spectra illustrate absorption bands of aliphatic, aromatic, and hetero-groups. They look similar to impsonite. Gamma radiation of up to 10 Mrad on slightly metamorphosed solid bitumens of the asphaltite category substantially changed their molecular structures. In addition to the predominance of aliphatic components, the content of condensed structures is also increased in the molecular structures. The increase in the share of aliphatic groups (as compared with natural samples) is probably explained by the fact that alkyl radicals, which occur in the structure and/or form by radiation processes, interact to form aliphatic products with both higher and lower molecular masses. This process is accompanied by the significant loss of heterofunctional groups, because they are usually less resistant to radiation than hydrocarbons. The loss of the functional group is one of the main processes that accompany their radiation. An increase in radiation dose up to 100 Mrad results in further notable changes of the asphaltite molecular structure, which are reflected by the substantial loss of some aliphatic, aromatic, condensed, and heterofunctional groups. According to these spectral characteristics, the substance becomes similar to natural lower anthraxolites. The IR spectra of kerites subjected to radiation of up to 10 and 100 Mrad appeared to be generally identical to each other in terms of the set and intensity of absorption bands. However, in addition to areas with the aromatic structure, some segments with the aliphatic structure (CH2 and CH3 groups) are also present in kerite subjected to radiation of up to 10 Mrad. These groups probably occur inside benzene rings or replace marginal hydrocarbon cycles. Consequently, this element may enter the structure of cyclic and aromatic compounds as a "stitcher." In addition, oxygen-bearing groups of the C--O type are also present, although in insignificant quantities. It can be assumed that radioactive decay breaks down C--C bonds and produces C--O structures due to the linkage with oxygen atoms or the detachment of the hydrogen atom nearest to the functional group.It should be noted that natural kerites represent a complex combination of planar polycyclic and linear (aliphatic) areas with different degrees of their structure ordering [2]; i.e., they contain substantially more aromatic fragments than asphaltites. The content of C=C oscillation groups in the benzene ring is probably retained owing to the high radiation resistance of benzene in the IR spectra of kerites subjected to radiation. In general, the structure of radiated kerites demonstrates features typical of natural high anthraxolies. Absorption bands disappear as a result of the increase in the carbon content in the bitumen structure and the consequent increase in the share of aromatic rings. Therefore, the IR spectra of anthraxolites after the radiation impact become similar to those of graphites, although the IR spectra of anthraxolites subjected to radiation of up to 10 Mrad still demonstrate weak absorption bands characteristic of the benzene ring. Thus it might be supposed that if solid bitumens can be extraterrestrial matter analog (asteroids) than it might be probable that the formation of the whole spectrum of solid bitumens from kerite-like to antraxolite-like can be the result of impact events on asteroids. The results show that, in addition to temperature and impact, radiation can also affect the process of coalification. Using carbonization of the asphaltite--kerite--anthraxolite series as an example, we have established that traces of the influence of high-energy radiation on a substance are reflected in the modification of its structure and the appearance of features similar to those of graphite. 1. N. P. Yushkin, Vestn. Inst. Geol., No. 9, 2 (1999) [in Russian]. 2. V. G. Melkov and A. M. Sergeeva. Role of Solid Carbonaceous Substances in the Formation of Endogenic Uranium Mineralization. (Nedra, Moscow, 1990) [in Russian]. ACKNOWLEDGMENTS I am grateful to V.V. Nazarov (VNIIEF) for the radiation treatment of bitumens and A.V. Andreev (EKO MVD RK) for the analysis of IR spectra. I'd like to thank A.V. Korochantsev for specimens kindly put at my disposal. This work was carried out within the framework of the Program of the RAS "Origin and Evolution of the Biosphere" with the financial support of the NSH-1014.2008.5, the RFBR (project no. 06-05-64755-а).
Gott, Garland B.; Erickson, Ralph L.
1952-01-01
Because of the common association of uranium and copper in several of the commercial uranium deposits in the Colorado Plateau Province, a reconnaissance was made of several known deposits of copper disseminated through sandstone to determine whether they might be a source of uranium. In order to obtain more information regarding the relationship between copper, uranium and carbonaceous materials, some of the uraniferious asphaltrite deposits in the Shinarump conglomerate along the west flank of the San Rafael Swell were also investigated briefly. During this reconnaissance 18 deposits were examined in New Mexico, eight in Utah, two in Idaho, and one each in Wyoming and Colorado. No uranium deposits of commercial grade are associated with the copper deposits that were examined. The uraniferous asphaltites in the Shinarump conglomerate of Triassic age on the west flank of the San Rafael Swell, however, are promising from the standpoint of commercial uranium production. Spectrographic analyses of crude oil, asphalt, and bituminous shales show a rather consistent suite of trace metals including vanadium, nickel, copper, cobalt, chromium, lead zinc, and molybdenum. The similarity of the metal assemblage, including uranium of the San Rafael Swell asphaltites, to the metal assemblage in crude oil and other bituminous materials suggests that these metals were concentrated in the asphaltites from petroleum. However, the hypothesis that uranium minerals were already present before the hydrocarbons were introduced and that some sort of replacement or uranium minerals by carbon compounds was effected after the petroleum migrated into the uranium deposit should not be disregarded. The widespread association of uranium with asphaltic material suggests that it also may have been concentrated by some agency connected with the formation of petroleum. The problem of the association of uranium and other trace metals with hydrocarbons should be studied further both in the field and in the laboratory.
NASA Technical Reports Server (NTRS)
Korochantsev, A. V.; Nikolaeva, O. V.
1993-01-01
The relationship between the chemical composition and the interlayer spacing (d002) of organic materials (OM's) is known for various terrestrial OM's. We improved this general trend by correlation with corresponding trend of natural solid bitumens (asphaltite-kerite-anthraxolite) up to graphite. Using the improved trend we identified bitumen analogs of carbonaceous chondrite OM's residued after HF-HCl treatment. Our laboratory experiment revealed that these analogs and, hence, structure and chemical composition of carbonaceous chondrite OM's are very sensitive to the HF-HCl treatment. So, usual extraction of OM from carbonaceous chondrites may change significantly structural and chemical composition of extracted OM.
Jones, Harriet Nell
1956-01-01
Native bituminous substances are divided into two groups, 1) bitumens and, 2) pyrobitumens. Bitumens are composed principally of hydrocarbons substantially free from oxygenated bodies, are fusible, and are soluble in carbon disulfide. Native bitumens occur in liquid and solid forms. The native liquid bitumens include all petroleums or crude oils. Native solid bitumens include native waxes such as ozocerite, asphalts or petroleum tars, and asphaltites such as gilsonite and grahamite. Pyrobitumens are composed principally of hydrocarbons which may contain oxygenated bodies. They are infusible and are insoluble, or nearly insoluble, in carbon disulfide. Native pyrobitumens are divided into an oxygen-containing group including peats, lignites, and coals, and an essentially oxygen-free, asphaltic group including such substances as wurtzilite, albertite, impsonite, and ingramite. Thucholites, which are carbonaceous substances that may contain uranium, thorium, and rare earths, commonly are considered to be pyrobitumens. Their compositions are variable and may fall into either the oxygen-containing or oxygen-free group. All varieties of native bituminous substances may be associated with mineral matter. The nomenclature of bitumens and pyrobitumens is used very loosely in the literature. This circumstance arises from the difficulty in recognizing many of these substances by visual examination, and because many of them can be identified accurately only by chemical methods. Inasmuch as some of the chemical procedures are time-consuming and satisfactory analytical methods have not been devised for all these substances, geologists generally have not obtained precise identifications but rather have used names that appeared most appropriate to the circumstances. It is expected that future research will show many substances called "asphaltite," "thucholite," etc., to be incorrectly identified. The nomenclature used by the authors of the various references of this bibliography is followed without deviation or further discussion. The stratigraphic nomenclature also is that used by the authors. In this bibliography emphasis is placed on reports dealing with the uranium contents and radioactivity of native bituminous substances rather than on mineralogical and chemical studies of these substances. The distribution of the substances described in the references is shown on the accompanying map. The indicated presence of these substances does not infer that they contain sufficient radioactive elements to constitute ores.
RELATIONSHIP OF URANIUM ORE DEPOSITS TO PETROLEUM AND GAS-BEARING STRUCTURES
DOE Office of Scientific and Technical Information (OSTI.GOV)
Russell, R.T.
eposits are located on producing or breached oil and gas structures, or in the immediate vicinity of such structures. Individual deposits associated with these structures contain ore reserves which may exceed one million tons. Data derived from a study of the known deposits should be useful in evaluating the potentiality of other areas where similar structural relations and abnormal radioactivity are known to exist. Uranium deposits located in producing oil or gas fields include a deposit of more than one million tons of uranium ore on a single salt dome in Texas, and uranium deposits in the Poison Basin, Wyoming,more » which are situated over a producing naturalgas structure, having a potential of 100,000 to 200,000 tons. Important uranium mining districts are also located near producing oil fields or near structures which may have contained oil at some time in the past. The Gas Hills district to Wyoming is on the flanks of a breached anticline and within one mile of natural-gas seeps. Deposits in the Brown's Park formation near Maybell, Colorado, are witin 10 miles of producing oil wells and natural-gas seeps are known within one mile of some of the uranium mines; and at Morrison, Colorado, uranium ore is associated with tar seeps. On th Colorado Plateau, large ore bodies with total reserves of at least 30 million tons of 0.3% U/sub 3/O/sub 8/ ore in the Ambrosia Lake district near Grants, New Mexico, and produce ore associated with asphaltite.'' The uraniferous asphaltite'' ore at Temple Mountain, Utah has been known for nearly 50 years. At both Circle Cliffs and the Inter- River area in Utah, uranium ore is associated with asphaltic material on anticlinal structures. Many other deposits are on breached strucIn Wyoming, uranium deposits in Tertiary sandstone and arkose generally lack carbon trash, but are located near oil or gas structures that contain hydrocarbons and natural gases capable of precititating uranium. Also, many uranium deposits on the Colorado Plateau have insufficient plant remains present to be the fixing agent for uranium, but petroleum and/or natural gas are proposed as possible extractants. The hydrogen sulfide contaned in natural gas or dissolved in oil-field water has been a factor in the formation of some uranium deposits. Oil-type structural traps must have been effective in localizing both petroleum and uranium ore in some districts. Although petroleum may contain small amounts of uranium, it is doubtful if either oil or natural gas are important transporting agents for uranium. Careful consideration of these various factors will provide a basis upon which to evaluate more effectively many ore producing areas. (auth)« less
Reflectance spectroscopy (350-2500 nm) of solid-state polycyclic aromatic hydrocarbons (PAHs)
NASA Astrophysics Data System (ADS)
Izawa, M. R. M.; Applin, D. M.; Norman, L.; Cloutis, E. A.
2014-07-01
Polycyclic aromatic hydrocarbons (PAHs) are organic compounds based on fused aromatic rings, and are formed in a variety of astrophysical, solar nebula and planetary processes. Polycyclic aromatic hydrocarbons are known or suspected to occur in a wide variety of planetary settings including icy satellites, Titan’s hazes, carbonaceous meteorites, comet nuclei, ring particles; and terrestrial organic-rich lithologies such as coals, asphaltites, and bituminous sands. Relatively few measurements of the visible and near-infrared spectra of PAHs exist, yet this wavelength region (350-2500 nm) is widely used for remote sensing. This study presents detailed analyses of the 350-2500 nm reflectance spectra of 47 fine-grained powders of different high-purity solid-state PAHs. Spectral properties of PAHs change with variations in the number and connectivity of linked aromatic rings and the presence and type of side-groups and heterocycles. PAH spectra are characterized by three strong features near ∼880 nm, ∼1145 nm, and ∼1687 nm due to overtones of νCH fundamental stretching vibrations. Some PAHs are amenable to remote detection due to the presence of diagnostic spectral features, including: Nsbnd H stretching overtones at 1490-1515 nm in NH- and NH2-bearing PAHs, aliphatic or saturated bond Csbnd H overtone vibrations at ∼1180-1280 nm and ∼1700-1860 nm; a broad asymmetric feature between ∼1450 nm and ∼1900 nm due to Osbnd H stretching overtones in aromatic alcohols, Csbnd H and Cdbnd O combinations near ∼2000-2010 nm and ∼2060-2270 nm in acetyl and carboxyl-bearing PAHs. Other substituents such as sulphonyl, thioether ether and carboxyl heterocycles, or cyano, nitrate, and aromatic side groups, do not produce well-resolved diagnostic spectral features but do cause shifts in the positions of the aromatic Csbnd H vibrational overtone features. Fluorescence is commonly suppressed by the presence of heterocycles, side-groups and in many non-alternant PAHs. The spectral characteristics of PAHs offer the potential, under suitable circumstances, for remote characterization of the classes of PAH present and in some cases, identification of particular heterocyclic or side-group substituents.
Insight into the nature and formation of the organic matter observed on Ceres
NASA Astrophysics Data System (ADS)
Ammannito, E.; Vinogradoff, V.; De Sanctis, M. C.; De Angelis, S.; Ferrari, M.; Ciarniello, M.; Raponi, A.; Raymond, C. A.; Russell, C. T.
2017-12-01
Observed by the Dawn spacecraft since March 2015, Ceres is a fascinating world [1]. Its surface, covered by phyllosilicates, carbonates, ammoniated-bearing hydrated minerals, water ice, salts and opaque materials indicates a complex chemical environment [1,2,3]. VIR, the Visible and InfraRed mapping spectrometer onboard the Dawn mission, has revealed the presence of aliphatic carbons with the 3.3-3.5 µm bands, near the Ernutet crater [4]. The origin of this OM is likely related to an endogenous source [4] and new issues are raised: what is the origin formation and the true nature of the OM hidden behind these aliphatic signatures? We used the spectral imaging (SPIM) facility in use at the laboratory of IAPS-INAF (spare of the VIR instrument onboard Dawn) to measure organic materials in the range 0.2-5.1 µm. These materials, such as insoluble organic matter (IOM) of chondrites, synthetic polymers, asphaltite, as well as spectra from literature data have been compared to VIR data. The Ceres aliphatic bands might match with an aliphatic branched polymer structure, i.e. with a 1.3 < CH2/CH3 ratio < 1.7, may contain some amine groups and likely some aromatic carbons such as chondritic IOM. Two hypotheses, which could be complementary, arise for the origin and formation of this OM: i) from internal processes only: due to past hydrothermal activity on Ceres [2], the circulation of H2-rich fluids during serpentinization processes with the presence of carbon dioxide might have led to Fischer-Tropsch-type reactions (methane and hydrocarbons formation [5]), subsequently processed during the pervasive hydrothermal alteration; ii) from interstellar heritage and internal processes: a part of the OM might have interstellar or protoplanetary precursors, coming from icy-grains, which were accreted into Ceres and undergone hydrothermal alteration with minerals. In either case, the partial differentiation of Ceres, might have driven the volatiles (i.e. the organic matter) near the surface. The second hypothesis, might also explain the high concentration of nitrogen. [1] Russell et al., (2016) Science, 353 (6303) 1008-1010. [2] De Sanctis et al., (2015) Nature 528, 241-244. [3] De Sanctis et al., (2016) Nature 536, 54- 57. [4] De Sanctis et al., (2017) Science, 355, 719-722. [5] Holm et al., (2015), Astrobiology, 15, 587-600.
A gallery of oil components, their metals and Re-Os signatures
NASA Astrophysics Data System (ADS)
Stein, Holly J.; Hannah, Judith L.
2016-04-01
Most sediment-hosted metallic ore deposits are one degree of freedom from hydrocarbon. That is, sulfide fluid inclusions may contain vestiges of travel in tandem with hydrocarbon-bearing fluids. For metallic ore deposits of stated metamorphic and magmatic origin, the degrees of freedom are several times more or, in some cases, no relationship exists. Still, the fetish for stereotyping and classifying ore types into hardline ore deposit models (or hybrid models when the data are wildly uncooperative) impedes our ability to move toward a better understanding of source rock. Fluids in the deeper earth, fluids in the crust, and the extraterrestrial rain of metals provide the Re-Os template for oil. So, too, this combination ultimately drives the composition of many metallic ore deposits. The world of crude oil and its complex history of maturation, migration, mixing, metal-rich asphaltene precipitation, and subsequent mobility of lighter and metal-poor components, is an untapped resource for students of ore geology. In the same way that Mississippi Valley-type lead and zinc deposits are described as the outcome of two converging and mixing fluids (metal-bearing and sulfur-bearing fluids), asphaltene precipitation can be an outcome of a lighter oil meeting and mixing with a heavier one. In the petroleum industry, this can spell economic disaster if the pore-space becomes clogged with a non-producible heavy oil or solid bitumen. In ore geology, sulfide precipitation on loss of permeability may create a Pb-Zn deposit. Petroleum systems provide a gallery of successive time-integrated Re-Os results. Heavy or biodegraded oils, if intersected by lighter oil or gas, can generate asphaltite or tar mats, and release a reservoir of still lighter oil (or gas). During this process there are opportunities for separation of metal-enriched aqueous fluids that may retain an imprint of their earlier hydrocarbon history, ultimately trapped in fluid inclusions. Salinity, temperature and pH are part of the equation controlling composition of metal-bearing aqueous fluids siphoned from residual hydrocarbons. The Re-Os isotopic behavior of oil components is generally specific to location and may differ within a single oil field, or even within discrete fractions of a single sample of oil [1]. Different fractions in a crude oil, for example maltenes and asphaltenes, can preserve signatures of unique sources. This should not be surprising, since economic geologists have long called upon meeting and mixing of metal-bearing with sulfur-bearing fluids from different sources. A time-integrated geologic history can also be derived from bitumen veins, with the Re-Os age of the metal source cached in these veins. Preservation of early metal and hydrocarbon history, and intact Re-Os systematics preserved in younger-formed systems have enormous potential for the resource industry. Several examples will be presented. [1] Georgiev, S.V., Stein, H.J., Hannah, J.L., Galimberti, R., Nali, M., Yang, G., and Zimmerman, A. (returned post revision, 11 Jan 2016) Re-Os dating of maltenes and asphaltenes within single samples of crude oils: Geochimica et Comochimica Acta. Supported by a consortium of petroleum companies under the CHRONOS project.