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Changchun, China

Hu X.-F.,Jilin University | Liu Z.-J.,Jilin University | Liu Z.-J.,Oil Shale Laboratory Center | Liu R.,Jilin University | And 6 more authors.
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

Clay mineral and inorganic geochemical characteristics of Eocene Huadian formation in Huadian basin have been found through X-ray diffraction, scanning electron microscopy and inorganic geochemical element tests. Clay minerals of Huadian formation of the study area contain montmorillonite, kaolinite and illite. The content of montmorillonite is the highest, and illite/smectite mixed layer is rare. Mn, Sr, P, Cd, Sr/Cu, B/Ga, Sr/Ba and Ca/(Ca+Fe) change with an exactly similar trend vertically, and Cu, Cs, Rb/Sr, V/(V+Ni) and δCe change with another similar trend. Clay minerals and inorganic geochemical evidence reveal the characteristics of paleoclimate and paleolimnology: the upper section containing coal and the lower section containing pyrite of Huadian formation belong to terrestrial sedimentary environment under the condition of warm and humid climate and low salinity; the middle section containing oil shale belongs to frequently alternating freshwater and saltwater environment, alternating humid and drought climate. The largest expansion phase of lacustrine basin which was under reduction condition with alternating humid and drought climate and salinity stratification developed semi-deep lake and deep lake facies which formed oil shale; the shrinkage phase of lacustrine basin with warm and humid climate developed delta plain with peat swamp which formed coal. Source


Sun P.-C.,Jilin University | Liu Z.-J.,Jilin University | Liu Z.-J.,Oil Shale Laboratory Center | Meng Q.-T.,Jilin University | And 5 more authors.
Meitan Xuebao/Journal of the China Coal Society | Year: 2011

On the basis of sequence straigraphy, three third-order sequences was divided in western basin, and oil shale occured in transgressive system tract and high stand system tract. Considering the characters of tectonic evolution, in the initial subsiding stage and the atrophic stage, Huadian Basin was filled with shallow water, and mainly develope alluvial fan, persistent fan-delta and shallow lake deposits, and the depth and scale of semi-deep and deep lacustrine dark mudstone were small. In the maximum subsidence stage, Huadian Basin was deep and stable. The intermittent fan-delt was deposited in the northeast part of this basin. The depth and scale of semi-deep and deep lacustrine dark mudstone reached to its maximum amount. Dozens of high-quality oil shale layers was deposited in this stage. Based on the distribution features of strata thickness, sedimentary facies, thickness of and oil yeild of oil shale, oil shale with the most high-quality and the maximum thickness was not deposited in the maximum depth water without sandbody, but was deposited in the deep water where was near the basin margin and without fan-delta. The interbedded of semi-deep lake and fan-delta front sediments brought nutrients into water, which caused high productivity of lake. During the deposition of semi-deep lake, the reduction deep water is the best place to preserve and get organic enrichment, then forme high-quality oil shale. Source

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