geochemistry – Page 2 – J.M.W Geo-Consulting

Geochemical composition of sedimentary rocks and imprint of hydrothermal fluid flow at the Variscan front – an example from the RWTH-1 well

Post author:jmw-geo
Post published:26th March 2012
Post category:publications

The RWTH-1 well within Aachen offers outstanding conditions for the study of Devonian to Carboniferous sedimentary rocks in the NW Rhenohercynian close to the Brabant Massif. The geochemical data obtained from core and cutting samples provide information on the depositional history (Lower Devonian, Siegenian, to Upper Carboniferous, Namurian to Westphalian) of the NW-Rhenohercynian basin and set constraints on the mineralogical and hydrothermal control on trace element abundance in the northern Eifel region (more…)

Assessment of acid-rock-drainage from epithermal Au-Ag mineralisations, Rio Turbio, San Juan, Argentina

Post author:jmw-geo
Post published:26th March 2012
Post category:publications

The Veladero district in the Rio Turbio Basin (San Juan, Argentina) consists of at least eight alteration zones within an area of 14 km2. It contains several large bulk-tonnage Au-Ag-deposits in altered, silicified volcanic rocks. The oxidized zone extends to considerable depth. The Veladero orebody occurs as a 750 m x 3000 m tabular body (more…)

World-wide Niobium and Tantalum Availability

Post author:jmw-geo
Post published:26th March 2012
Post category:publications

Niobium is a shiny, white, soft, and ductile metal with superconductive properties. Niobium products are used in a wide variety of applications. The largest end market for HSLA steel is for large diameter steel pipelines for the transmission of natural gas and oil. Price increases in oil and natural gas during the last years have created a new interest in exploration for, and (more…)

The effect of hydrothermal alteration and metamictisation on the U-Th-Pb- distribution and U-Pb-systematics of pyrochlore of the Sokli carbonatite complex, N-Finland

Post author:jmw-geo
Post published:26th March 2012
Post category:publications

Pyrochlore is a common accessory mineral in granite pegmatites, nepheline syenites and carbonatites. Its ability to accomodate many different elements lead to a wide range of pyrochlore varieties. This is obvious for the U- and Th- contents. The Sokli carbonatite complex is part of the Kola alkaline province (KAP) in the northern Baltic Shield. The complex is situated in the area of Savukoski, Finish Lapland, close to the border to Russia. The emplacement age of 360 – 370 Ma falls in (more…)

Mineralogy and geochemistry of vents formed on the burning coal mining waste dump Anna I, Alsdorf, Germany

Post author:jmw-geo
Post published:26th March 2012
Post category:publications

The coal mining waste dump Anna I of the Anna black coal underground mine in Alsdorf (Germany) – in operation between 1854 and 1983 – is characterized by internal combustion. Volatile products of this process are emitted though vent-like holes and fractures on the top of the dump. Surface temperatures are heterogeneous within a dm-scale and partly exceed 210 degrees centigrade. The pH of condensed vapour (more…)

Pyrochlore Composition As Indicator For The Carbonatite Evolution Stages At Sokli?

Post author:jmw-geo
Post published:26th March 2012
Post category:publications

Pyrochlore is a common accessory mineral in granite pegmatites, nepheline syenites and carbonatites. The general chemical formular is A2-mB2X6-wY1-n • pH2O where A includes Na, Ca, U, Th , Pb, REE, Ba and Sr; B includes Nb, Ta, Ti, Zr and Fe; X = O and OH; Y = O, OH and F. The ability to accomodate many different elements leads to a wide range of pyrochlore varieties.
In Sokli (Finland) pyrochlore composition (more…)

U-Th-Pb- elemental and isotopic distribution of pyrochlore minerals from the Sokli carbonatite complex, N-Finland

Post author:jmw-geo
Post published:26th March 2012
Post category:publications

Pyrochlore, ideally (Ca,Na)2(Nb5O6)(OH,F), is a relatively common accessory mineral in many rock-types including carbonatites. In the Sokli carbonatite, N. Finland, pyrochlore concentrates to economically important amounts, where it forms the ore mineral of niobium. (more…)