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reconstructing seafloor age distributions in lost ocean basins

Geoscience Frontiers 2021年第2期12卷 769-780页

作者： Simon Williams Nicky m.Wright John Cannon Nicolas Flament r.dietmar müller Department of Geology Northwest UniversityXi’an710069China State Key Laboratory of Continental Dynamics Northwest UniversityXi’an710069China research School of Earth Sciences The Australian National UniversityACT2601Australia ArC Centre of Excellence for Climate Extremes The Australian National UniversityACT2601Australia EarthByte Group School of GeosciencesUniversity of SydneyAustralia GeoQuEST research Centre School of EarthAtmospheric and Life SciencesUniversity of WollongongNorthfields AvenueNSW2522Australia

reconstructions of past seafloor age make it possible to quantify how plate tectonic forces,surface heat flow,ocean basin volume and global sea level have varied through geological ***,past ocean basins that have now been subducted cannot be uniquely reconstructed,and a significant challenge is how to explore a wide range of possible ***,we investigate possible distributions of seafloor ages from the late Paleozoic to present using published full-plate reconstructions and a new,efficient seafloor age reconstruction workflow,all developed using the open-source software *** test alternative reconstruction models and examine the influence of assumed spreading rates within the Panthalassa Ocean on the reconstructed history of mean seafloor age,oceanic heat flow,and the contribution of ocean basin volume to global sea *** reconstructions suggest variations in mean seafloor age of~15 myr during the late Paleozoic,similar to the amplitude of variations previously proposed for the Cretaceous to *** reconstructed oceanic age-area distributions are broadly compatible with a scenario in which the long-period fluctuations in global sea level since the late Paleozoic are largely driven by changes in mean seafloor *** suggestions of a constant rate of seafloor production through time can be modelled using our workflow,but require that oceanic plates in the Paleozoic move slower than continents based on current reconstructions of continental motion,which is difficult to reconcile with geodynamic studies.

关键词： Plate reconstructions Sea level Seafloor spreading

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Global kinematics of tectonic plates and subduction zones since the late Paleozoic Era

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Geoscience Frontiers 2019年第3期10卷 989-1013页

作者： Alexander Young Nicolas Flament Kayla maloney Simon Williams Kara matthews Sabin Zahirovic r.dietmar müller School of Earth and Environmental Sciences University of Wollongong EarthByte Group School of Geosciences The University of Sydney Sydney Informatics Hub The University of Sydney

Detailed global plate motion models that provide a continuous description of plate boundaries through time are an effective tool for exploring processes both at and below the Earth's surface. A new generation of numerical models of mantle dynamics pre-and post-Pangea timeframes requires global kinematic descriptions with full plate reconstructions extending into the Paleozoic(410 ma). Current plate models that cover Paleozoic times are characterised by large plate speeds and trench migration rates because they assume that lowermost mantle structures are rigid and fixed through time. When used as a surface boundary constraint in geodynamic models, these plate reconstructions do not accurately reproduce the present-day structure of the lowermost mantle. Building upon previous work, we present a global plate motion model with continuously closing plate boundaries ranging from the early Devonian at 410 ma to present *** analyse the model in terms of surface kinematics and predicted lower mantle structure. The magnitude of global plate speeds has been greatly reduced in our reconstruction by modifying the evolution of the synthetic Panthalassa oceanic plates, implementing a Paleozoic reference frame independent of any geodynamic assumptions, and implementing revised models for the Paleozoic evolution of North and South China and the closure of the rheic Ocean. Paleozoic(410-250 ma) rmS plate speeds are on average ～8 cm/yr, which is comparable to mesozoic-Cenozoic rates of ～6 cm/yr on *** global median values of trench migration trend from higher speeds(～2.5 cm/yr) in the late Devonian to rates closer to 0 cm/yr at the end of the Permian(～250 ma), and during the mesozoic-Cenozoic(250-0 ma) generally cluster tightly around ～1.1 cm/yr. Plate motions are best constrained over the past 130 myr and calculations of global trench convergence rates over this period indicate median rates range between 3.2 cm/yr and 12.4 cm/yr with a present day median rate estimat

关键词： Tectonic reconstruction Paleozoic Plate velocities Subduction zone kinematics Lower mantle structure South China

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Bayesian geological and geophysical data fusion for the construction and uncertainty quantification of 3D geological models

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Geoscience Frontiers 2021年第1期12卷 479-493页

作者： Hugo K.H.Olierook richard Scalzo David Kohn rohitash Chandra Ehsan Farahbakhsh Chris Clark Steven m.reddy r.dietmar müller School of Earth and Planetary Sciences Curtin UniversityGPO Box U1987PerthWA6845Australia Centre for Translational Data Science University of SydneyNSW2006SydneyAustralia Sydney Informatics Hub University of SydneyNSW2006SydneyAustralia EarthByte Group School of GeosciencesUniversity of SydneyNSW2006SydneyAustralia Timescales of mineral Systems and John de Laeter Centre Curtin UniversityGPO Box U1987PerthWA6845Australia School of mathematics and Statistics University of New South WalesSydneyNSW2052Australia Department of mining Engineering Amirkabir University of Technology(Tehran Polytechnic)TehranIran

Traditional approaches to develop 3D geological models employ a mix of quantitative and qualitative scientific techniques,which do not fully provide quantification of uncertainty in the constructed models and fail to optimally weight geological field observations against constraints from geophysical ***,using the Bayesian Obsidian software package,we develop a methodology to fuse lithostratigraphic field observations with aeromagnetic and gravity data to build a 3D model in a small(13.5 km×13.5 km)region of the Gascoyne Province,Western *** approach is validated by comparing 3D model results to independently-constrained geological maps and cross-sections produced by the Geological Survey of Western *** fusing geological field data with aeromagnetic and gravity surveys,we show that 89%of the modelled region has>95%certainty for a particular geological unit for the given model and *** boundaries between geological units are characterized by narrow regions withrtainty,which are typically 400-1000 m wide at the Earth's surface and 500-2000 m wide at ***~4 km depth,the model requires geophysical survey data with longer wavelengths(e.g.,active seismic)to constrain the deeper *** Obsidian was originally built for sedimentary basin problems,there is reasonable applicability to deformed terranes such as the Gascoyne ***,modification of the Bayesian engine to incorporate structural data will aid in developing more robust 3D ***,our results show that surface geological observations fused with geophysical survey data can yield reasonable 3D geological models with narrow uncertainty regions at the surface and shallow subsurface,which will be especially valuable for mineral exploration and the development of 3D geological models under cover.

关键词： Capricorn orogen machine learning Bayesian inference markov chain monte Carlo Solid earth mineral exploration

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Decoding earth’s plate tectonic history using sparse geochemical data

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Geoscience Frontiers 2020年第1期11卷 265-276页

作者： michael G.Tetley Zheng-Xiang Li Kara J.matthews Simon E.Williams r.dietmar müller EarthByte Group School of GeosciencesUniversity of SydneyNSWAustralia Seismological Laboratory California Institute of TechnologyPasadenaCAUSA Data61 CSIROAustralian Technology ParkNSWAustralia Earth Dynamics research Group The Institute for Geoscience Research(TIGeR)School of Earth and Planetary SciencesCurtin University of TechnologyGPO Box U1987PerthWA 6845Australia

Accurately mapping plate boundary types and locations through time is essential for understanding the evolution of the plate-mantle system and the exchange of material between the solid Earth and surface ***,the complexity of the Earth system and the cryptic nature of the geological record make it difficult to discriminate tectonic environments through deep *** we present a new method for identifying tectonic paleo-environments on Earth through a data mining approach using global geochemical *** first fingerprint a variety of present-day tectonic environments utilising up to 136 geochemical data attributes in any available combination.A total of 38301 geochemical analyses from basalts aged from 5-0 ma together with a well-established plate reconstruction model are used to construct a suite of discriminatory models for the first order tectonic environments of subduction and mid-ocean ridge as distinct from intraplate hotspot oceanic environments,identifying 41,35,and 39 key discriminatory geochemical attributes,*** training and validation,our model is applied to a global geochemical database of 1547 basalt samples of unknown tectonic origin aged between 1000-410 ma,a relatively ill-constrained period of Earth’s evolution following the breakup of the rodinia supercontinent,producing 56 unique global tectonic environment predictions throughout the Neoproterozoic and Early *** are used to discriminate between three alternative published rodinia configuration models,identifying the model demonstrating the closest spatio-temporal consistency with the basalt record,and emphasizing the importance of integrating geochemical data into plate *** approach offers an extensible framework for constructing full-plate,deeptime reconstructions capable of assimilating a broad range of geochemical and geological observations,enabling next generation Earth system models.

关键词： Plate tectonics Geochemistry Geodynamics Supercontinents rodinia Big data

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Earth’s tectonic and plate boundary evolution over 1.8 billion years

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Geoscience Frontiers 2024年第6期15卷 429-453页

作者： Xianzhi Cao Alan S.Collins Sergei Pisarevsky Nicolas Flament Sanzhong Li Derrick Hasterok r.dietmar müller Frontiers Science Center for Deep Ocean multispheres and Earth System Key Lab of Submarine Geosciences and Prospecting TechniquesMOE and College of Marine GeosciencesOcean University of ChinaQingdao 266100China Tectonics and Earth Systems&mineral Exploration Cooperative research Centre School of PhysicsChemistry and Earth SciencesThe University of AdelaideAdelaideSA 5005Australia Earth Dynamics research Group School of Earth and Planetary SciencesCurtin UniversityWA 6845Australia Environmental Futures School of EarthAtmospheric and Life SciencesUniversity of WollongongNorthfields AvenueNSW 2522Australia EarthByte Group School of GeosciencesThe University of SydneyNSW 2006Australia

Understanding the intricate relationships between the solid Earth and its surface systems in deep time necessitates comprehensive full-plate tectonic reconstructions that include evolving plate boundaries and oceanic *** particular,a tectonic reconstruction that spans multiple supercontinent cycles is important to understand the long-term evolution of Earth’s interior,surface environments and mineral ***,we present a new full-plate tectonic reconstruction from 1.8 Ga to present that combines and refines three published models:one full-plate tectonic model spanning 1 Ga to present and two continental-drift models focused on the late Paleoproterozoic to mesoproterozoic *** model is constrained by geological and geophysical data,and presented as a relative plate motion model in a paleomagnetic reference *** model encompasses three supercontinents,Nuna(Columbia),rodinia,and Gondwana/Pangea,and more than two complete supercontinent cycles,covering40%of the Earth’s *** refinements to the base models are focused on times before 1.0 Ga,with minor changes for the *** times between 1.8 Ga and 1.0 Ga,the root mean square speeds for all plates generally range between 4 cm/yr and 7 cm/yr(despite short-term fast motion around 1.1 Ga),which are kinematically consistent with post-Pangean plate tectonic *** time span of the existence of Nuna is updated to between 1.6 Ga(1.65 Ga in the base model)and 1.46 Ga based on geological and paleomagnetic *** follow the base models to leave Amazonia/West Africa separate from Nuna(as well as Western Australia,which only collides with the remnants of Nuna after initial break-up),and South China/India separate from *** to the concept of a“boring billion”,our model reveals a dynamic geological history between 1.8 Ga and 0.8 Ga,characterized by supercontinent assembly and breakup,and continuous accretion *** model is publicly accessible,providing a framework for

关键词： Plate reconstruction Nuna Supercontinent Proterozoic Paleogeography

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Subsidence history and forming mechanism of anomalous tectonic subsidence in the Bozhong depression, Bohaiwan basin

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Science China Earth Sciences 2007年第9期50卷 1310-1318页

作者： müller r. dietmar School of Geosciences University of Sydney Sydney NSW 2006 Australia

The Bozhong depression of the Bohaiwan basin belongs to a family of extensional basins in East China, but is quite different from other parts of the basin. The Cenozoic subsidence of the depression is controlled by a combination of lithospheric thinning and polycyclic strike-slip movements. Three episodic rifts have been identified, i.e. Paleocence-early Eocene, middle-late Eocene and Oligocene age. The depression underwent syn-rift and post-rift stages, but two episodic dextral movement events of the strike-slip faults modify the subsidence of the Bozhong depression since the Oligocene. The early dextral movement of the Tan-Lu fault associated with crustal extension resulted in accelerated subsidence during the time of deposition of the Dongying Formation with a maximum thickness of 4000 m. A late reactivation of dextral movement of the Tan-Lu fault began in late miocene (about 12 ma), which resulted in the intense subsidence of minghuazhen Formation and Quaternary. In addition, dynamic mantle convection-driven topography also accelerated the post-rift anomalous subsidence since the miocene (24.6 ma). Our results indicate that the primary control on rapid subsidence both during the rift and post-rift stages in the Bozhong depression originates from a combination of multiple episodic crustal extension and polycyclic dextral movements of strike-slip faults, and dynamic topography.

关键词： tectonic subsidence strike-slip dynamic topography Bozhong depression Bohaiwan basin

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Impact of hyperglycemia on autoimmune pancreatitis and regulatory T-cells

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World Journal of Gastroenterology 2018年第28期24卷 3120-3129页

作者： Franz-Tassilo müller-Graff Brit Fitzner robert Jaster Brigitte Vollmar.dietmar Zechner Institute for Experimental Surgery Rostock University Medical Center Division of Gastroenterology Department of Medicine Ⅱ Rostock University Medical Center

AIm To evaluate the influence of hyperglycemia on the progression of autoimmune *** We induced hyperglycemia by repetitive intraperitoneal(ip) injection of 50 mg/kg streptozotocin in mrL/mp J mice, which develop autoimmune pancreatitis due to a genetic predisposition. We compared the extent of inflammation(histological score, CD3^+ lymphocytes, CD8^+ T-cells, CD4^+ T-cells, Foxp3^+ T-helper cells) in the pancreas of hyperglycemic and normoglycemic mice. We also analyzed the number of leukocytes, lymphocytes, granulocytes and monocytes in the blood. In addition, we determined the percentage of CD3^+ lymphocytes, CD8^+ T-cells, CD4^+ T-cells, Foxp3^+ T-helper cells, Foxp3^+ CD25^+ T-helper and Foxp3^+T-helper cells in the spleen by flow *** Treatment with streptozotocin caused a strong induction of hyperglycemia and a reduction in body weight(P re hyperglycemia did not, however, lead to an aggravation, but rather to a slight attenuation of autoimmune pancreatitis. In the pancreas, both the histological score of the pancreas as well as the number of CD3+ lymphocytes(P re decreased by hyperglycemia. No major changes in the percentage of CD8^+ T-cells, CD4^+ T-cells, Foxp3^+ T-helper cells were observed between hyperglycemic and normoglycemic mice. Hyperglycemia increased the numbers of leukocytes(P mphocytes(P = 0.016), granulocytes and monocytes(P = 0.001) in the blood. Hyperglycemia also moderately reduced the percentage of CD3^+ lymphocytes(P = 0.057), significantly increased the percentage of Foxp3^+ T-helper cells(P = 0.018) and Foxp3^+ CD25^+ T-helper cells(P = 0.021) and reduced the percentage of Foxp3^+T-helper cells(P = 0.034) in the spleen. CONCLUSION Hyperglycemia does not aggravate but moderately attenuates autoimmune pancreatitis, possibly by increasing the percentage of regulatory T-cells in the spleen.

关键词： Autoimmune disease Diabetes Treg FoxP3 Autoimmune pancreatitis mrL/mpJ mice

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Effect of wall rougheners on cross-sectional flow characteristics for non-spherical particles in a horizontal rotating cylinder

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Particuology 2014年第1期12卷 44-53页

作者： Guang Lu James r.Third Christoph r.müller ETH Zürich Department of Mechanical and Process Engineering Institute of Energy Technology Laboratory of Energy Science and Engineering8092 Zürich Switzerland

Discrete-element-method （DEm） simulations have been performed to investigate the cross-sectional flow of non-spherical particles in horizontal rotating cylinders with and without wall rougheners. The non-spherical particles were modeled using the three-dimensional super-quadric equation. The influence of wall rougheners on flow behavior of grains was studied for increasing particle blockiness. moreover, for approximately cubic particles （squareness parameters [555]）, the rotational speed, gravitational acceleration and particle size were altered to investigate the effect of wall rougheners under a range of operating conditions. For spherical and near-spherical particles （approximately up to the squareness parameters [344]）, wall rougheners are necessary to prevent slippage of the bed against the cylinder wall. For highly cubic particle geometries （squareness parameters larger than [3441）, wall rougheners resulted in a counter-intuitive decrease in the angle of repose of the bed. In addition, wall rougheners employed in this study were demonstrated to have a higher impact on bed dynamics at higher rotational speeds and lower gravitational accelerations. Nevertheless, using wall rougheners had a comparatively small influence on particle-flow characteristics for a bed composed of finer grains.

关键词： Granular flowNon-spherical particlesrotating cylinderDiscrete element method (DEm)Kiln

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Heterogeneity of mature oligodendrocytes in the central nervous system

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Neural regeneration research 2025年第5期20卷 1336-1349页

作者： Chao Weng Adam m.r.Groh moein Yaqubi Qiao-Ling Cui Jo Anne Stratton G.r.Wayne moore Jack P.Antel Neuroimmunology Unit Montreal Neurological Institute-HospitalDepartment of Neurology and NeurosurgeryMcGill UniversityMontrealQCCanada Department of Neurology Renmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina

mature oligodendrocytes form myelin sheaths that are crucial for the insulation of axons and efficient signal transmission in the central nervous *** evidence has challenged the classical view of the functionally static mature oligodendrocyte and revealed a gamut of dynamic functions such as the ability to modulate neuronal circuitry and provide metabolic support to *** the recognition of potential heterogeneity in mature oligodendrocyte function,a comprehensive summary of mature oligodendrocyte diversity is *** delve into early 20th-century studies by robertson and río-Hortega that laid the foundation for the modern identification of regional and morphological heterogeneity in mature ***,recent morphologic and functional studies call into question the long-assumed homogeneity of mature oligodendrocyte function through the identification of distinct subtypes with varying myelination ***,modern molecular investigations,employing techniques such as single cell/nucleus rNA sequencing,consistently unveil at least six mature oligodendrocyte subpopulations in the human central nervous system that are highly transcriptomically diverse and vary with central nervous system *** and disease related mature oligodendrocyte variation denotes the impact of pathological conditions such as multiple sclerosis,Alzheimer's disease,and psychiatric ***,caution is warranted when subclassifying mature oligodendrocytes because of the simplification needed to make conclusions about cell identity from temporally confined *** studies leveraging advanced techniques like spatial transcriptomics and single-cell proteomics promise a more nuanced understanding of mature oligodendrocyte *** research avenues that precisely evaluate mature oligodendrocyte heterogeneity with care to understand the mitigating influence of species,sex,central nervous system region,age,and disease,

关键词： aging central nervous system diseases electron microscopy heterogeneity immunohistochemistry myelin sheath natural history neuroglia oligodendroglia single-cell gene expression analysis

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East African topography and volcanism explained by a single,migrating plume

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Geoscience Frontiers 2020年第5期11卷 1669-1680页

作者： rakib Hassan Simon E.Williams michael Gurnis dietmar muller School of Geosciences Room 412Madsen Building F09 Eastern AvenueThe University of SydneyNSW2006Australia Seismological Laboratory California Institute of TechnologyPasadenaCA91125USA Now at Geoscience Australia GPO Box 378CanberraACT2601Australia State Key Laboratory of Continental Dynamics Department of GeologyNorthwest UniversityXi’an 710069China

Anomalous topographic swells and Cenozoic volcanism in east Africa have been associated with mantle *** models involving one or more fixed plumes beneath the northeastward migrating African plate have been suggested to explain the space-time distribution of magmatism in east *** devise paleogeographically constrained global models of mantle convection and,based on the evolution of flow in the deepest lower mantle,show that the Afar plume migrated southward throughout its *** models suggest that the mobile Afar plume provides a dynamically consistent explanation for the spatial extent of the southward propagation of the east African rift system(EArS),which is difficult to explain by the northeastward migration of Africa over one or more fixed plumes alone,over the last≈45 *** further show that the age-progression of volcanism associated with the southward propagation of EArS is consistent with the apparent surface hotspot motion that results from southward motion of the modelled Afar plume beneath the northeastward migrating African *** models suggest that the Afar plume became weaker as it migrated southwards,consistent with trends observed in the geochemical record.

关键词： Numerical mantle flow models Deep mantle flow LLSVP morphology Plume dynamics Plume motion Dynamic topography

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