Author:Victor P. Nechaev, Achim Bechtel, Shifeng Dai, Igor Yu Chekryzhov, Boris I. Pavlyutkin, Sergey V. Vysotskiy, Alexander V. Ignatiev, Tatiana A. Velivetskaya, Wenmu Guo, Irina A. Tarasenko, Evgeniya V. Nechaeva, David French, JamesC. Hower
Abstract
A total of 23coal and two carbonaceous shale samples of the EarlyCretaceous-Miocene, collected from different basins in the Primoryeand Sakhalin regions of Russia, and the Hunchun basin of northeasternChina, were used in this study for determination of major oxides (byAES and XRF), trace elements (by ICP-MS), sulfur, carbon, carbonisotopes, and major components of extractable organic matter(wet-chemical and gas-chromatographic analyses). Interpretation ofthe obtained data was intended to elucidate geodynamic and othergeological processes controlling bio-geochemical compositions andcritical element mineralization of the studied coals. The datasuggest that inorganic matter in the studied coals was derived mainlyfrom the Paleozoic granites and the Cenozoic felsic and intermediatetuffs. The Early Eocene and, in particular, Oligocene epochsrepresent the two major mineralization events in the regions,resulting in enrichment of Ge, W, Be, Mo, Sb, Sr, Ba, REY (rare earthelements and Y), Th, and U in the coals. The two events were relatedrespectively to the Indo-Eurasian collision followed by platereorganization in the Pacific and the opening of the Sea of Japan.The geodynamic changes were probably associated with mantle-derivedvolcanic activity and intensive degassing, which enhanced thecapability of surficial and ground waters to leach and redistributetrace metals. Organic matter played a significant role in the systemof mineralization, starting from weathering of source rocks andending at the coal diagenetic stage. Organic acids significantlyaccelerated leaching and transportation of the metals, while they,together with sulfate-reducing bacteria, kerogen, alcohols ketones,and n-alkanolsin particular, an important role in metal precipitation, mainlythrough reactions of cation exchange and adsorption.
Keywords: Coal; Early cretaceous; Cenozoic; Critical elements; Organic matter; Geodynamic events