Selected translations of the Russian literature on the electrogeochemical sampling technique called CHIM (chastichnoe izvlechennye metallov)

USGS Publications Warehouse

Bloomstein, Edward I.; Bloomstein, Eleana; Hoover, D.B.; Smith, D.B.

1990-01-01

As part of our research into new methods for the assessment of mineral deposits, the U.S. Geological Survey has recently begun investigation of the CHIM method. As part of our studies, translation of a Russian manual on the CHIM methodology and eight articles from the Russian literature were transit ted to provide background for our own research. The translations were done by Earth Science Translation Services of Albuquerque, New Mexico, and are presented as received, without editing on our part. Below is a bibliography of the translated articles.For approximately the past 20 years Russian geoscientists have been applying an electrogeochemical sampling technique given the Russian acronym CHIM, derived from Chastichnoe Izvlechennye Metallov which translates as "partial extraction of metals". In this technique a direct current is introduced into the earth through collector electrodes similar to "porous pots" used in electrical geophysical applications. The solution in the cathode is dilute nitric acid, and current is passed through the cathode for times ranging from 6 hours to 48 hours or more. Electrical connections to the nitric acid are made through an inner conductor that is typically spectroscopically pure graphite. At the cathode, mobile cations collect on the graphite or in the nitric acid solution, both of which serve as the geochemical sampling media. These media are then analyzed by appropriate methods for the ions of interest. In most applications of the CHIM method only mobile cations are sampled, although Russian literature does refer to collection of anions as well. More recently the CHIM method has been applied by the Peoples Republic of China and the Indian Geological Survey.The literature indicates that the method has advantages over other geochemical sampling techniques by providing increased sensitivity to the metals being searched for, especially where deposits are covered by substantial overburden. In some cases success has been claimed with

Sulfur in Earth's Mantle and Its Behavior During Core Formation

NASA Technical Reports Server (NTRS)

Chabot, Nancy L.; Righter,Kevin

2006-01-01

The density of Earth's outer core requires that about 5-10% of the outer core be composed of elements lighter than Fe-Ni; proposed choices for the "light element" component of Earth's core include H, C, O, Si, S, and combinations of these elements [e.g. 1]. Though samples of Earth's core are not available, mantle samples contain elemental signatures left behind from the formation of Earth's core. The abundances of siderophile (metal-loving) elements in Earth's mantle have been used to gain insight into the early accretion and differentiation history of Earth, the process by which the core and mantle formed, and the composition of the core [e.g. 2-4]. Similarly, the abundance of potential light elements in Earth's mantle could also provide constraints on Earth's evolution and core composition. The S abundance in Earth's mantle is 250 ( 50) ppm [5]. It has been suggested that 250 ppm S is too high to be due to equilibrium core formation in a high pressure, high temperature magma ocean on early Earth and that the addition of S to the mantle from the subsequent accretion of a late veneer is consequently required [6]. However, this earlier work of Li and Agee [6] did not parameterize the metalsilicate partitioning behavior of S as a function of thermodynamic variables, limiting the different pressure and temperature conditions during core formation that could be explored. Here, the question of explaining the mantle abundance of S is revisited, through parameterizing existing metal-silicate partitioning data for S and applying the parameterization to core formation in Earth.

Chondritic Mn/Na ratio and limited post-nebular volatile loss of the Earth

NASA Astrophysics Data System (ADS)

Siebert, Julien; Sossi, Paolo A.; Blanchard, Ingrid; Mahan, Brandon; Badro, James; Moynier, Frédéric

2018-03-01

The depletion pattern of volatile elements on Earth and other differentiated terrestrial bodies provides a unique insight as to the nature and origin of planetary building blocks. The processes responsible for the depletion of volatile elements range from the early incomplete condensation in the solar nebula to the late de-volatilization induced by heating and impacting during planetary accretion after the dispersion of the H2-rich nebular gas. Furthermore, as many volatile elements are also siderophile (metal-loving), it is often difficult to deconvolve the effect of volatility from core formation. With the notable exception of the Earth, all the differentiated terrestrial bodies for which we have samples have non-chondritic Mn/Na ratios, taken as a signature of post-nebular volatilization. The bulk silicate Earth (BSE) is unique in that its Mn/Na ratio is chondritic, which points to a nebular origin for the depletion; unless the Mn/Na in the BSE is not that of the bulk Earth (BE), and has been affected by core formation through the partitioning of Mn in Earth's core. Here we quantify the metal-silicate partitioning behavior of Mn at deep magma ocean pressure and temperature conditions directly applicable to core formation. The experiments show that Mn becomes more siderophile with increasing pressure and temperature. Modeling the partitioning of Mn during core formation by combining our results with previous data at lower P-T conditions, we show that the core likely contains a significant fraction (20 to 35%) of Earth's Mn budget. However, we show that the derived Mn/Na value of the bulk Earth still lies on the volatile-depleted end of a trend defined by chondritic meteorites in a Mn/Na vs Mn/Mg plot, which tend to higher Mn/Na with increasing volatile depletion. This suggests that the material that formed the Earth recorded similar chemical fractionation processes for moderately volatile elements as chondrites in the solar nebula, and experienced limited post

Impact of Acid Mine Drainage on the hydrogeological system at Sia, Cyprus

NASA Astrophysics Data System (ADS)

Ng, Stephen; Malpas, John

2013-04-01

Discontinued mining of the volcanogenic massive sulphide ore bodies of Cyprus has left significant environmental concerns including Acid Mine Drainage. Remnant sulphide ore and tailings in waste dumps react with oxygenated rainwater to produce sulphuric acid, a process which is multiplied when metal-loving acidophilic bacteria are present. Given that Cyprus has a Mediterranean climate, characterized by its warm and dry summers and cool and wet winters, the low pH effluent with high levels of trace elements, particularly metals, is leached out of the waste tips particularly during the wet season. The Sia site includes an open mine-pit lake, waste rock and tailings dumps, a river leading to a downstream dam-lake, and a localised groundwater system. The study intends to: identify the point source and nature of contamination; analyze the mechanism and results of local acid generation; and understand how the hydrogeological system responds to seasonal variations. During two sampling campaigns, in the wet and dry seasons of 2011, water samples were collected from the mine pit lake, from upstream of the adjacent river down to the dam catchment, and from various boreholes close to the sulphide mine. The concentration of ions in waters varies between wet and dry seasons but, in both, relative amounts are directly related to pH. In the mine-pit lake, Fe, Mn, Mg, Cu, Pb, Zn, Ni, Co and Cd are found in higher concentrations in the dry season, as a result of substantial evaporation of water. The Sia River runs continuously in the wet season, and waters collected close to the waste tips have pH as low as 2.5 and higher concentrations of Al, Cu, Fe and Zn. Further downstream there is a significant decrease in trace metal contents with a concomitant rise of pH. Al and Fe dominate total cation content when pH is lower than 4. Al is derived from the weathering of clay minerals, especially during the wet season. Fe is derived from the oxidation of pyrite. Once pH's exceed 4, a white