Wakefieldite-(La), LaVO4 , a new mineral species from the Glucksstern Mine, Friedrichroda, Thuringia, Germany

Wakefieldite-(La), ideally LaVO4, is a new mineral from the long abandoned Glücksstern Mine, Gottlob hill, Friedrichroda, Thuringia, Germany. The mineral occurs as light pinkish to brown prismatic crystals up to 0.5 mm in length. Wakefieldite-(La) is associated with hausmannite, baryte and gottlobite. The streak is white, the Mohs hardness 4 and the luster adamantine. The crystals are transparent to translucent. Electron microprobe analysis (more…)

Continue ReadingWakefieldite-(La), LaVO4 , a new mineral species from the Glucksstern Mine, Friedrichroda, Thuringia, Germany

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

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…)

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

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

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…)

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

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

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…)

Continue ReadingThe 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

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

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…)

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

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

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…)

Continue ReadingPyrochlore Composition As Indicator For The Carbonatite Evolution Stages At Sokli?

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

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…)

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