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 extens...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.展开更多
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 temporal...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.1500 Ma to ca.1400 Ma),Jixian section,Tianjin City,North China show that:1) there is a definite interface or lining,rich in organic material and pyrite,between the MT crack-filling calcite microspar and the micritic host rock,which is also rich in organic matter;2) the micritic host rocks are notable for the absence of stromatolites and microbial laminites;3) distinctive conglomeratic lag deposits made up of intraclasts of MT microspar result from storm reworking of the MT structures;4) the MT structure is associated with possible algal megafossils such as Chuaria;5) the MT microspar is made up of the larger calcite crystal and the MT crack is marked by the diversity of configurations;6) both the TOC content and the carbon-isotopic value(δ^(13)C_(PDB)) among the host rock, the MT microspar and the possible algae fossil are obviously different.For the forming mechanism of the Gaoyuzhuang MT structure,these features can still indicate that:A) the MT microspar was formed by rapid precipitation and lithification;B) the MT microspar precipitated directly within the cracks; C) the decomposition of organic matter within the host micrite might be the chief mechanism producing gas bubbles;D) microscale gas-sediment interaction led to the generation of the MT cracks and the precipitation of microspar therein;E) the MT cracks might represent the track of migration and expansion of gas bubbles,and that the recrystallization of host micrites cannot be eliminated during forming process of the MT microspar;F) the MT structure is 展开更多
The maximum flooding event and condensed section are one hot subject in modern se-quence stratigraphy and cyclic stratigraphy. Condensed section (CS)is defined as very thinabyssal or bathyal facies stratigraphic unit,...The maximum flooding event and condensed section are one hot subject in modern se-quence stratigraphy and cyclic stratigraphy. Condensed section (CS)is defined as very thinabyssal or bathyal facies stratigraphic unit, with extremely low rate of sedimentation andbroad extension at the maximum flooding age. It is an important indicator fordetermination of the maximum flooding event. In recent years, the coneeption ofcondensed section has been opened up in not only its formation depth but also thedistributive scope after the discovery of glauconitic CS in North China Platform inCambrian by the aothors, and the condensed section is defined as the low-rate marinestratigraphic unit formed at the maximum flooding stage. It is the key to age determinationand correlation of craton basinal sequence.展开更多
Various orders of condensed sections are recognized in the Cambrian of North China Carbonate Platform. Study of comparative sedimentology proves that CS4-CS5 in the Changshanian age is the maximum sea flooding sedimen...Various orders of condensed sections are recognized in the Cambrian of North China Carbonate Platform. Study of comparative sedimentology proves that CS4-CS5 in the Changshanian age is the maximum sea flooding sediments in the Cambrian, regardless of the distribution, thickness, internal structure of the condensed section series and K2O abundance. It is a two-layered composite condensed section series, characterized by the enrichment of such elements as K, P, Mn, Ti, Co, V, Cr, Cu, Zr, Ni, Li, Th, La, Ce, Nd, Dy, Y, Sc and Be. The Changshanian maximum flooding event can be correlated on a global scale, and the corresponding sedimentary records are discovered in 26 intercontinental sections in N. Europe, N. America, and Tarim and the Yangtze Platform of China. Through detailed sedimentological research, meter-scale cycle analysis and Fischer plots, it is concluded that the Changshanian maximum flooding was a composite effect of the second-order eustacy superimposed by the third-and fourth-order eustacy, which lasted for 1.2-3 Ma. An intercontinental model of the Changshanian maximum flooding is proposed at the end of this paper.展开更多
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...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.展开更多
基金part of the project "Regional Geology and the Potential Analysis of Petroleum Exploration in Guizhou and Guangxi" (No.1008/2-6) financed by China Petrochemical Corporation (SINOPEC)
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.
基金the project"A Study of the Cycles and Events for the Mesoproterozoic Jixian System in the Yan Mountain Region,northern China"(Nos.49802012, 40472065)financially supported by the National Foundation of Natural Sciences of China
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.1500 Ma to ca.1400 Ma),Jixian section,Tianjin City,North China show that:1) there is a definite interface or lining,rich in organic material and pyrite,between the MT crack-filling calcite microspar and the micritic host rock,which is also rich in organic matter;2) the micritic host rocks are notable for the absence of stromatolites and microbial laminites;3) distinctive conglomeratic lag deposits made up of intraclasts of MT microspar result from storm reworking of the MT structures;4) the MT structure is associated with possible algal megafossils such as Chuaria;5) the MT microspar is made up of the larger calcite crystal and the MT crack is marked by the diversity of configurations;6) both the TOC content and the carbon-isotopic value(δ^(13)C_(PDB)) among the host rock, the MT microspar and the possible algae fossil are obviously different.For the forming mechanism of the Gaoyuzhuang MT structure,these features can still indicate that:A) the MT microspar was formed by rapid precipitation and lithification;B) the MT microspar precipitated directly within the cracks; C) the decomposition of organic matter within the host micrite might be the chief mechanism producing gas bubbles;D) microscale gas-sediment interaction led to the generation of the MT cracks and the precipitation of microspar therein;E) the MT cracks might represent the track of migration and expansion of gas bubbles,and that the recrystallization of host micrites cannot be eliminated during forming process of the MT microspar;F) the MT structure is
基金Subject supported by the National Natural Science Foundation of China, Royal Society of UK and China Association for Science and Technology.
文摘The maximum flooding event and condensed section are one hot subject in modern se-quence stratigraphy and cyclic stratigraphy. Condensed section (CS)is defined as very thinabyssal or bathyal facies stratigraphic unit, with extremely low rate of sedimentation andbroad extension at the maximum flooding age. It is an important indicator fordetermination of the maximum flooding event. In recent years, the coneeption ofcondensed section has been opened up in not only its formation depth but also thedistributive scope after the discovery of glauconitic CS in North China Platform inCambrian by the aothors, and the condensed section is defined as the low-rate marinestratigraphic unit formed at the maximum flooding stage. It is the key to age determinationand correlation of craton basinal sequence.
文摘Various orders of condensed sections are recognized in the Cambrian of North China Carbonate Platform. Study of comparative sedimentology proves that CS4-CS5 in the Changshanian age is the maximum sea flooding sediments in the Cambrian, regardless of the distribution, thickness, internal structure of the condensed section series and K2O abundance. It is a two-layered composite condensed section series, characterized by the enrichment of such elements as K, P, Mn, Ti, Co, V, Cr, Cu, Zr, Ni, Li, Th, La, Ce, Nd, Dy, Y, Sc and Be. The Changshanian maximum flooding event can be correlated on a global scale, and the corresponding sedimentary records are discovered in 26 intercontinental sections in N. Europe, N. America, and Tarim and the Yangtze Platform of China. Through detailed sedimentological research, meter-scale cycle analysis and Fischer plots, it is concluded that the Changshanian maximum flooding was a composite effect of the second-order eustacy superimposed by the third-and fourth-order eustacy, which lasted for 1.2-3 Ma. An intercontinental model of the Changshanian maximum flooding is proposed at the end of this paper.
基金supported by the National Natural Science Foundation of China(Nos.41772095,42072136,41972108,42106144)the Natural Science Foundation of Shandong Province(Nos.ZR2019MD027,ZR2020QD089,ZR2021QE125)+4 种基金SDUST Research Fund(No.2015TDJH101)Scientific and Technological Innovation Project Financially Supported by Qingdao National Laboratory for Marine Science and Technology(No.2016ASKJ13)Major Innovation Projects of Key R&D Program of Shandong Province(No.2019JZZY020808)the Foundation of SINOPEC(No.P20059-7)Innovation and Entrepreneurship Training program for College students(Nos.202110424157,202110424158)。
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.
