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3篇 您的检索式:作者名="Maurice E.Tucker"
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1Facies-succession and architecture of the third-order sequences and their stratigraphic framework of the Devonian in Yunnan-Guizhou-Guangxi area,South China显示文摘The Caledonian orogeny at the end of the Silurian resulted in great changes in the palaeogeography in the Yunnan-Guizhou-Guangxi area of South China; the continental area of the Early Paleozoic evolved into the extensive Dian-Qian-Gui Sea in the Late Paleo-zoic. Early in the Devonian, as a result of a major transgression, seawater encroached gradually from the south to the north and clastic facies were deposited. Carbonate deposition was then established in the Yunnan-Guizhou-Guangxi area, with a palaeogeography marked by attached platforms, isolated platforms and narrow basins. As a result of the Ziyun movement towards the end of the Devonian, the Upper Devonian strata are regressive and thin out from the open-sea to the land areas. A study of the nature and distribution of sedimentary facies in space and time recognises 13 third-order sequences in the Devonian strata in Yunnan-Guizhou-Guangxi area, and these form two second-order sequences. The strata of the Lower Devonian comprise 5 third-order sequences (SQ1 to SQ5 ), which are dominated by transgressive clastics. 4 third-order sequences (SQ6 to SQ9 ) in the Middle Devonian are characterized by alternations of transgressive clastics and highstand carbonates. In the Upper Devonian, carbonates constitute 4 third-order sequences (SQ10 to SQ13 ), which are generally marked by the transgressive limestones and highstand dolomites. On the basis of earlier biostratigraphic studies, sea-level changes represented by the third-order sequences with their different facies successions are explored, and the sequence stratigraphic framework is established. There-fore, the Devonian strata in the study area provide an example for further understanding of depositional trends within the sequence-stratigraphic framework.Mei Mingxiang Maurice E.Tucker 2013Journal of Palaeogeography2013,2,1:6
2Molar Tooth Structure:a Contribution from the Mesoproterozoic Gaoyuzhuang Formation,Tianjin City,North China显示文摘Molar-tooth(MT) structure is an enigmatic sedimentary structure consisting of variously-shaped cracks and voids filled with a characteristically uniform,equant calcite microspar.It is globally distributed but temporally restricted to rocks from Neoarchean to Neoproterozoic age.The origin of MT structures has been debated for more than a century and the topic continues to be highly contentious.Some features of MT structure occurring in micritic limestones of the Mesoproterozoic Gaoyuzhuang Formation(ca.15...Maurice E.TUCKER 2011Acta Geologica Sinica(English Edition)2011,85,5:4
3Difference in calcium ion precipitation between free and immobilized Halovibrio mesolongii HMY2显示文摘Biomineralization has become a research focus in wastewater treatment due to its much lower costs compared to traditional methods.However,the low sodium chloride(NaCl)-tolerance of bacteria limits applications to only water with low NaCl concentrations.Here,calcium ions in hypersaline wastewater(10%NaCl)were precipitated by free and immobilized Halovibrio mesolongii HMY2 bacteria and the differences between them were determined.The results show that calcium ions can be transformed into several types of calcium carbonate with a range of morphologies,abundant organic functional groups(C-H,C-O-C,C=O,etc),protein secondary structures(β-sheet,α-helix,3_(10)helix,andβ-turn),P=O and S-H indicated by P2p and S2p,and more negativeδ^(13)C_(PDB)(‰)values(-16.8‰to-18.4‰).The optimal conditions for the immobilized bacteria were determined by doing experiments with six factors and five levels and using response surface method.Under the action of two groups of immobilized bacteria prepared under the optimal conditions,by the 10^(th)day,Ca^(2+)ion precipitation ratios had increased to 79%-89%and 80%-88%with changes in magnesium ion cencentrations.Magnesium ions can significantly inhibit the calcium ion precipitation,and this inhibitory effect can be decreased under the action of immobilized bacteria.Minerals induced by immobilized bacteria always aggregated together,had higher contents of Mg,P,and S,lower stable carbon isotope values and less well-developed protein secondary structures.This study demonstrates an economic and eco-friendly method for recycling calcium ions in hypersaline wastewater,providing an easy step in the process of desalination.Huaxiao Yan Meiyu Huang Jihan Wang Heding Geng Xiyu Zhang Ziyang Qiu Yongliang Dai Zuozhen Han Yudong Xu Long Meng Lanmei Zhao Maurice E.Tucker Hui Zhao 2022Journal of Environmental Sciences2022,34,12:0
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