Lithospheric structure and Mesozoic geodynamics of the eastern Central Asian orogen

The lithospheric structure of several marginal and interior units of the eastern Central Asian orogen has been explored in 2D geophysical models. The obtained constraints on effective parameters (density, resistivity, temperature) of lithospheric blocks and their boundaries allowed correlation of geophysical structures to tectonic settings. The geological and geophysical (including paleomagnetic) data were used jointly to model the present structure of the lithosphere along 126° E between 56° N and 40° N and to construct a palinspastic model of the same area for the latest Early Jurassic (175 Ma).     

绿色撒哈拉

占非洲面积将近三分之一的撒哈拉沙漠一度是热带稀树大草原,野生动植物种类丰富,充满鱼类的湖泊星罗棋布,而且有许多古人类生活在那里。“在约5 550~10 500年以前,撒哈拉是理想的生存地带,”斯特凡·克洛普林这样说过。克洛普林是德国科隆大学的地质考古学家,在过去的30年里,他     

Precise Determination of Cadmium, Indium and Tellurium Using Multiple Collector ICP-MS

New sample preparation and ion-exchange separation methods as well as instrumental measurement protocols were established for the determination of trace-level Cd, In, and Te concentrations in geological materials by isotope-dilution mass spectrometry. High precision isotope ratio measurements were performed with a multiple collector inductively coupled plasma-mass spectrometer (MC-ICP-MS). The mass biases incurred for In and Te were corrected by adding and monitoring Pd and Sb standard solutions, respectively. Mass fractionation of Cd was corrected by using the mass fractionation factor calculated from the measurement of a standard solution. The measurement precision was better than 1 % for Cd, In and Te. Detection limits were < 1 ng g^-1 for Cd, < 0.02 ng g^-1 for In and Te. Using these new analytical techniques, the concentrations of Cd, In and Te were determined in six international geological reference materials. Concentrations could be reproduced within 3% for Cd, 4% for In and 10% for Te. Sample heterogeneity and volatility problems might have been the reason for the relatively large differences between Te replicates. Our results displayed excellent reproducibility compared with those of other techniques and agree well with data from previously published recommended values.