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Molar Tooth Structure:a Contribution from the Mesoproterozoic Gaoyuzhuang Formation,Tianjin City,North China

Acta Geologica Sinica(english edition) 2011年第5期85卷 1084-1099页

作者： maurice e.tucker Department of earth Sciences Durham University

Molar-tooth(MT) structure is an enigmatic sedimentary structure consisting of variously-shaped cracks and voids filled with a characteristically uniform,equant calcite *** is globally distributed but temporally restricted to rocks from Neoarchean to Neoproterozoic *** origin of MT structures has been debated for more than a century and the topic continues to be highly *** 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 *** 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 proc

关键词： Molar-tooth structure Mesoproterozoic limestone Gaoyuzhuang Formation Tianjin North China

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Facies-succession and architecture of the third-order sequences and their stratigraphic framework of the Devonian in Yunnan-Guizhou-Guangxi area,South China

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Journal of Palaeogeography 2013年第1期2卷 93-108页

作者： Mei Mingxiang maurice e.tucker School of earth Science and Mineral Resources China University of Geosciences (Beijing) Department of Geological Sciences University of Durham

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.

关键词： sequence stratigraphy Devonian Yunnan-Guizhou-Guangxi area South China

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Difference in calcium ion precipitation between free and immobilized Halovibrio mesolongii HMY2

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Journal of environmental Sciences 2022年第12期34卷 184-200页

作者： 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 College of Chemical and Biological engineering College of Safety and Environmental EngineeringCollege of Earth Science and EngineeringShandong University of Science and TechnologyQingdao 266590China Laboratory for Marine Mineral Resources Center for Isotope Geochemistry and GeochronologyQingdao National Laboratory for Marine Science and TechnologyQingdao 266237China School of earth Sciences University of BristolBristol BS81RJUK Cabot Institute University of BristolCantock’s CloseBristol BS81UJUK

Biomineralization has become a research focus in wastewater treatment due to its much lower costs compared to traditional ***,the low sodium chloride(NaCl)-tolerance of bacteria limits applications to only water with low NaCl ***,calcium ions in hypersaline wastewater(10%NaCl)were precipitated by free and immobilized Halovibrio mesolongii HMY2 bacteria and the differences between them were *** 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 *** 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 *** ions can significantly inhibit the calcium ion precipitation,and this inhibitory effect can be decreased under the action of immobilized *** 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 *** study demonstrates an economic and eco-friendly method for recycling calcium ions in hypersaline wastewater,providing an easy step in the process of desalination.

关键词： Biomineralization Halovibrio mesolongii Hypersaline wastewater Calcium ion removal Intracellular aragonite

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Carbonate platform evolution:from a bioconstructed platform margin to a sand-shoal system(Devonian,Guilin,South China)

Carbonate platform evolution:from a bioconstructed platform ...

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中国科学院地质与地球物理研究所2002学术年会

作者： maurice e.tucker Department of Geological Sciences University of Durham

The depositional organization and architecture of the middle-late Devonian Yangdi rimmed carbonate platform margin in the Guilin area of South China were related to oblique, extensional faulting in a strike-slip *** platform margin shows two main stages of construction in the late Givetian to Frasnian,with a bioconstructed margin evolving into a sand-shoal *** the late Givetian,the platform margin was rimmed with microbial buildups composed mainly of cyanobacterial colonies(mostly Renalcis and epiphyton).These grew upwards and produced an aggradational(locally slightly retrogradational) architecture with steep foreslope *** depositional sequences(S3-S5) are recognized in the upper Givetian strata,which are dominated by extensive ***-scale depositional cyclicity occurs in most facies associations,except in the platform-margin buildups and upper foreslope *** the latest Givetian(at the top of sequence S5),relative platform uplift(±subaerial exposure) and associated rapid basin subsidence(probably a block-tilting effect) caused large-scale platform collapse and slope erosion to give local scalloped embayments along the platform margin and the synchronous demise of microbial ***,sand shoals and banks composed of ooids and peloids and,a little later,stromatoporoid buildups on the palaeohighs,developed along the platform margin, from which abundant loose sediment was transported downslope to form gravity-flow deposits. Another strong tectonic episode caused further platform collapse in the early Frasnian(at the top of sequence S6),leading to large-scale breccia release and the death of the stromatoporoid buildups. Siliceous facies(banded cherts and siliceous shales) were then deposited extensively in the basin centre as a result of the influx of hydrothermal *** platform-margin sand-shoal/bank system, possibly with gullies on the slope,persisted into the latest Frasnian until the restoration of micr

关键词： Carbonate platform microbially rimmed platform margin sand-shoal system South China

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Long-distance correlation between tectonic-controlled,isolated carbonate platforms by cyclostratigraphy and sequence stratigraphy in the Devonian of South China

Long-distance correlation between tectonic-controlled,isolat...

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中国科学院地质与地球物理研究所2001学术年会

作者： maurice e.tucker Department of Geological Sciences University of Durham

During the early Middle Devonian in South China,an extensive carbonate platform was broken up through extension to create a complex pattern of platforms,and interplatform *** Givetian and Frasnian carbonate successions,five depositional facies,including peritidal,restricted shallow subtidal,semi-restricted subtidal,intermediate subtidal and deep subtidal facies,and 18 lithofacies units are recognized from measured sections on three isolated *** deposits are arranged into metre-scale,upward-shallowing peritidal and subtidal *** third-order sequences are identified from changes in cycle stacking patterns,vertical facies changes and the stratigraphic distribution of subaerial exposure *** sequences mostly consist of a lower transgressive part and an upper regressive part. Transgressive packages are dominated by thicker-than-average subtidal cycles, and regressive packages by thinner-than-average peritidal *** boundaries are transitional zones composed of stacked,high-frequency, thinner-than-average cycles with upward-increasing intensity of subaerial exposure,rather than individual,laterally traceable *** sequences can be further grouped into catch-up and keep-up sequence sets from the long-term (second-order) changes in accommodation and vertical facies changes. Catch-up sequences are characterized by relatively thick cycle packages with a high percentage of intermediate to shallow subtidal facies,and even deep subtidal facies locally within some individual sequences,recording long-term accommodation ***-up sequences are characterized by relatively thin cycle packages with a high percentage of peritidal facies within sequences,recording long-term accommodation *** of long-term accommodation changes expressed by Fischer plots reveals that during the late Givetian to early Frasnian increased accommodation loss on platforms coincided with increased accommodation gain in interplatform basins.

关键词： Cyclostratigraphy Frasnian.Givetian high-frequency cyclicity isolated platforms platform carbonate correlation South China

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Carbon isotope excursions and sea-level change:Implications for the Frasnian-Famennian biotic crisis

Carbon isotope excursions and sea-level change:Implications ...

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中国科学院地质与地球物理研究所2002学术年会

作者： maurice e.tucker Johan Yans Alain Preat Department of Geological Sciences University of Durham Faculte Polytechnique de Mons Departement des Sciences de la Terre Universite Libre de Bruxelles

New carbon and oxygen isotope data from carbonates spanning the Frasnian-Famennian(F-F) boundary in the Guilin area,South China,show a broad positive dC rise and fall,with sharp,short-lived negative dC events;this pattern is comparable to that in europe and North *** integration of the isotope stratigraphy with high-resolution sequence stratigraphy corroborates the onset of the positive dC excursion during a third-order sea-level fall in the latest *** can best be explained through increased burial of C during the sea-level fall,brought about by increased organic productivity caused by increased continent-derived nutrient flux to the ocean due to enhanced weathering through the proliferation of land plants in the *** scenario would have resulted n anoxic and eutrophic conditions over epicontinental seas and blooms of cyanobacteria,creating a highly stressful and fragile ecosystem for oligotrophic normal-marine benthic organisms and leading to their massive *** global third-order sea-level fall near the end of the Frasnian may have led to gas hydrate dissociation(giving the negative dC events),and caused wild climatic *** subsequent short-term events of sea-level rise,anoxia and eutrophication in the latest part of the F-F transition would have placed additional environmental stresses on the already-weakened biota,leading to their further demise.

关键词： South China Devonian mass extinction δ13C sequence stratigraphy

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Organic accumulation in the lower Chihsia Formation(Middle Permian) of South China:Constraints from pyrite morphology and multiple geochemical proxies

Organic accumulation in the lower Chihsia Formation(Middle P...

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中国科学院地质与地球物理研究所2012年度（第12届）学术年会

作者： Hengye Wei Daizhao Chen Jianguo Wang Hao Yu maurice e.tucker Key Laboratory of Petroleum Resources Research Institute of Geology and Geophysics Chinese Academy of Sciences College of earth Science East China Institute of Technology School of earth Sciences University of BristolBS8 1RJEnglandUnited Kingdom

The organic-rich Chihsia Formation(Middle Permian) on the Yangtze platform,western Hubei,South China, is considered to he the major hydrocarbon source rock in South *** lower part of the Chihsia Formation,reported here,was deposited in an intrashelf basin and is characterised by black laminated marlstones/shales intercalated with dark-grey limestones/dolomites in which metre-scale shallowing(or cleaning)-upward cycles are *** cycle is composed of basal marlstone/shale and upper limestone. The organic matter is concentrated exclusively in the shaley bases of these cycles,and shows systematic, cyclic variations in abundance up through the *** integrated approach of pyrite morphology and multiple geochemical proxies was used to determine the mechanism of organic *** the organic-rich sediments,many redox proxies,including pyrite framboid size distribution,C-S-Fe relation-ships, iron speciation,andδS values of pyrite suggest deposition beneath the dysoxic bottom water, which evolved into a more oxic water body when the organic-poor limestones were ***, the coincidence of increased abundance of total organic carbon(TOC) with increased Ba and Mo contents indicates that organic matter accumulation was controlled mainly by primary *** data indicate that increased organic accumulation resulted mainly from higher organic carbon export with increased nutrient flux during superimposed sea-level rises of different *** in turn could have increased the oxygen consumption by respiration of microorganisms and organic matter decay,leading to the depletion of oxygen in the water ***,the rapid sedimentation rate further limited bioturbation and organic matter decomposition,facilitating the preservation of buried organic matter.

关键词： Chihsia Formation Middle Permian Primary productivity Redox state Organic matter Yangtze platform

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Development and characterization of 3D-printed electroconductive pHeMA-co-MAA NP-laden hydrogels for tissue engineering

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Bio-Design and Manufacturing 2024年第3期7卷 262-276页

作者： Sara De Nitto Aleksandra Serafin Alexandra Karadimou Achim Schmalenberger John J.eMulvihill maurice N.Collins DIBRIS Polytechnic Inter-School Section University of Genoa16126 GenoaItaly School of engineering Bernal InstituteUniversity of LimerickLimerick V94 T9PXIreland School of Natural Sciences Department of Biological SciencesUniversity of LimerickLimerick V94 T9PXIreland Health Research Institute University of LimerickLimerick V94 T9PXIreland AMBeR University of LimerickLimerick V94 T9PXIreland

Tissue engineering(Te)continues to be widely explored as a potential solution to meet critical clinical needs for diseased tissue replacement and tissue *** this study,we developed a poly(2-hydroxyethyl methacrylate-co-methacrylic acid)(pHeMA-co-MAA)based hydrogel loaded with newly synthesized conductive poly(3,4-ethylene-dioxythiophene)(PeDOT)and polypyrrole(PPy)nanoparticles(NPs),and subsequently processed these hydrogels into tissue engineered constructs via three-dimensional(3D)*** presence of the NPs was critical as they altered the rheological properties during ***,all samples exhibited suitable shear thinning properties,allowing for the development of an optimized processing window for 3D *** were 3D printed into pre-determined disk-shaped configurations of 2 and 10 mm in height and diameter,*** observed that the NPs disrupted the gel crosslinking efficiencies,leading to shorter degradation times and compressive mechanical properties ranging between 450 and 550 *** conductivity of the printed hydrogels increased along with the NP concentration to(5.10±0.37)×10^(−7)S/*** vitro studies with cortical astrocyte cell cultures demonstrated that exposure to the pHeMA-co-MAA NP hydrogels yielded high cellular viability and proliferation ***,hydrogel antimicrobial studies with staphylococcus epidermidis bacteria revealed that the developed hydrogels affected bacterial *** together,these materials show promise for various Te strategies.

关键词： Conductive nanoparticles Hydroxyethyl methacrylate(HeMA) Ultraviolet(UV)polymerization 3D printing

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Nonlinear Rydberg exciton-polaritons in Cu2O microcavities

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Light(Science & Applications) 2024年第4期13卷 619-627页

作者： Maxim Makhonin Anthonin Delphan Kok Wee Song Paul Walker Tommi Isoniemi Peter Claronino Konstantinos Orfanakis Sai Kiran Rajendran Hamid Ohadi Julian Heckötter Marc Assmann Manfred Bayer Alexander Tartakovskii maurice Skolnick Oleksandr Kyriienko Dmitry Krizhanovskii Department of Physics and Astronomy University of SheffieldSheffield S37RHUK. Department of Physics and Astronomy University of ExeterStocker RoadExeter EX44PYUK. SUPA School of Physics and AstronomyUniversity of St AndrewsSt Andrews KY169SSUK. Fakultät Physik TU DortmundAugust-Schmidt-Straße 444227 DortmundGermany

Rydberg excitons(analogues of Rydberg atoms in condensed matter systems)are highly excited bound electron-hole states with large Bohr *** interaction between them as well as exciton coupling to light may lead to strong optical nonlinearity,with applications in sensing and quantum information ***,we achieve strong effective photon–photon interactions(Kerr-like optical nonlinearity)via the Rydberg blockade phenomenon and the hybridisation of excitons and photons forming polaritons in a Cu2O-filled *** pulsed resonant excitation polariton resonance frequencies are renormalised due to the reduction of the photon-exciton coupling with increasing exciton *** analysis shows that the Rydberg blockade plays a major role in the experimentally observed scaling of the polariton nonlinearity coefficient as∝n4.4±1.8 for principal quantum numbers up to n=*** high principal quantum numbers studied in a polariton system for the first time are essential for realisation of high Rydberg optical nonlinearities,which paves the way towards quantum optical applications and fundamental studies of strongly correlated photonic(polaritonic)states in a solid state system.

关键词： density Rydberg polar

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Milankovitch-driven cycles in the Precambrian of China:The Wumishan Formation

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Journal of Palaeogeography 2013年第4期2卷 369-389页

作者： Mei Mingxiang maurice e. tucker State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences (Beijing) Department of earth Sciences University of Durham

Carbonate strata of the Mesoproterozoic Wumishan Formation in the Jixian area near Tianjin are ~3300 m thick and were deposited over some 100 million years(from ~1310±20 Ma to ~1207±10 Ma).Metre-scale cycles(parasequences) dominate the *** are generally of the peritidal carbonate type,and mostly show an approximately symmetrical lithofacies succession with thick stromatolite biostromes and small thromboliteoncolite bioherms constituting the central part and tidal-flat dolomites forming the upper and lower ***-supratidal dolomitic shales with palaeosol caps make up the topmost *** boundaries of the Wumishan cycles are typically exposure surfaces,and there is abundant evidence for fresh-water *** 1:4 stacking patterns indicate that the individual Wumishan cycles are sixthorder parasequences,with 4 parasequences constituting one fifth-order parasequence ***,5-8 beds or couplets,can be discerned in some of the *** regular vertical stacking pattern of beds within the sixth-order parasequences,forming the fifth-order parasequence sets,are interpreted as the result of environmental fluctuations controlled by Milankovitch rhythms,namely the superimposition of precession,and short and *** widespread 1:4 stacking pattern in the cyclic succession,as well as the local 1:5-8 stacking patterns of the beds within the cycles,suggest that the Milankovitch rhythms had similar ratios in the Mesoproterozoic as in the *** on the cycle stacking patterns,26 thirdorder sequences can be distinguished and these group into 6 second-order,transgressiveregressive megasequences(or sequence sets),all reflecting a composite,hierarchical succession of relative sea-level changes.

关键词： peritidal carbonate cycles Milankovitch rhythms Wumishan Formation Mesoproterozoic Tianjin North China

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