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Modeling Magma Dynamics with a Mixed Fourier Collocation-Discontinuous Galerkin Method

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Communications in Computational Physics 2011年第7期10卷 433-452页

作者： Alan R.Schiemenz Marc A.Hesse Jan S.Hesthaven Department of geological Sciences Brown UniversityProvidenceRI 02910USA division of Applied Mathematics Brown UniversityProvidenceRI 02910USA Department of geological Sciences University of Texas at AustinAustinTX 78712USA Department of Earth and Environmental Sciences GeophysicsMunich UniversityTheresienstr.4180333 MunichGermany

A high-order discretization consisting of a tensor product of the Fourier collocation and discontinuous Galerkin methods is presented for numerical modeling of magma *** physical model is an advection-reaction type system consisting of two hyperbolic equations and one elliptic *** high-order solution basis allows for accurate and efficient representation of compaction-dissolution waves that are predicted from linear *** discontinuous Galerkin method provides a robust and efficient solution to the eigenvalue problem formed by linear stability analysis of the physical *** insights into the processes of melt generation and segregation,such as melt channel bifurcation,are revealed from two-dimensional time-dependent simulations.

关键词： Magma dynamics discontinuous Galerkin method Fourier collocation method numerical simulations linear stability analysis

The role of mechanical stratigraphy in the lateral variations of thrust development along the central Alberta Foothills, Canada

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Geoscience Frontiers 2018年第5期9卷 1451-1464页

作者： Hyunjung Lee Yirang Jang Sanghoon Kwon Myong-Ho Park Gautam Mitra Department of Earth System Sciences Yonsei University Geology & Geophysics Department POSCO DAEWOO Corp. geological Research division Korea Institute of Geoscience and Mineral Resources Department of Earth and Environmental Sciences University of Rochester

Fold-thrust belts generally exhibit significant variations in structural styles such as differences in thrust geometries and frequencies in imbrication. A natural laboratory of this pattern is preserved in the central Alberta Foothills of the Canadian Rockies, where differences in thrust geometries are represented by the existence vs. non-existence of triangle zones. To seek the factors that make this difference in these regions in terms of structural geometry, stratigraphic thickness variations and mechanical stratigraphy of the sedimentary layers, structural interpretation is conducted based on admissible cross-sections and well log interpretations. In northern region, a backthrust is detached from an incompetent layer(*** Unit of the Wapiabi Formation), which gets thinner from the Foothills to the Plains, indicating that it is developed where the shale layers are pinched out where triangle zone is developed. Backthrust is also developed in the southern region, where mechanical strengths of strata(viz. Bearpaw Formation)increase toward the foreland. In the central region, however, only forethrusts are developed along the weak continuous decollement layers(viz. Turner Valley and Brazeau formations), forming an imbricate fan without development of the triangle zone. Incompetent layers such as the top Wapiabi(Nomad),Brazeau(Bearpaw), Coalspur and Paskapoo formations are also pinched out laterally, forming fault glide horizons in different stratigraphic levels in each region. These results indicate that, along the transport direction, triangle zone is developed in relation to the stratigraphic pinch out of the Nomad Unit in the northern region, and is formed associated with the variations in strengths of the layers constituting the Bearpaw Formation in the southern region. It is notable that all the glide horizons are developed along incompetent layers. However, triangle zones are not developed in the areas of continuous stratigraphy of the Nomad Unit, which doe

关键词： Mechanical stratigraphy Triangle zone Imbricate fan Central Alberta Foothills Canadian rockies

Clay minerals in the late Quaternary sediment of Tulare Lake,California: Implications for climate change, weathering, and erosion processes

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International Journal of Sediment Research 2019年第5期34卷 432-443页

作者： Junhua Guo Christine Pyles William Krugh Rob Negrini Department of geological Sciences California State UniversityBakersfield

The clay mineralogy of Tulare Lake sediment was examined to investigate hydroclimatic and environmental changes in the southern Sierra Nevada Mountains(SNM) since the most recent glacial *** of clay mineral assemblages elucidates significant changes in weathering, erosion, and hydroclimatic condition in the catchment. During the last glacial period(24.4–15.1 cal ka BP), low illite content implies less physical erosion of the granitic batholith rocks and a cold and arid environment in the southern SNM. Abrupt increases of illite content at 21.8–20.8 and 17.6 cal ka BP resulted from the glacier advances to the ablation zone and illite-rich glacier flour was transported down to the lake. The gradual increase of smectite induced by progressive depletion of illite-rich glacier flour from 17.6 cal ka BP toward the end of this period indicates climate was beginning to get warm and wet. From 11.9 to5.3 cal ka BP, two warm and wet periods(10.7–9.4 and 8.2–5.2 cal ka BP) were characterized by high smectite/illite content ratios and low illite crystallinity values, suggesting intensive rainfall precipitation and more physical erosion in the highland and lowland catchment as well as more smectite formation in the terrace soils. Since the last glacial period, physical erosion, in comparison to the chemical weathering,was the dominant process responding to the hydroclimatic change in the Tulare Lake *** to weak chemical weathering was signified by the mostly low illite chemical weathering index of the core sediments. Such results suggest that vegetation cover in the southern SNM was low and limited.

关键词： Clay mineralogy Sierra Nevada Mountains Glaciers Weathering Tulare Lake

Ion Probe Study of Silicate Inclusions from Colomera (ⅡE) Iron Meteorite: the Rare Earth Element Perspective

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Acta Geologica Sinica(English Edition) 2004年第5期78卷 1060-1074页

作者： HSU Weibiao CA 91125 California Institute of Technology China division of geological & Planetary Sciences Chinese Academy of Sciences Laboratory for Astrochemistry and Planetary Sciences Purple Mountain Observatory Nanjing 210008 Pasadena USA

Coupled with a petrographical study, I carried out an ion probe study of rare earth element microdistributions in mineral phases of silicate inclusions from the Colomera ⅡE iron meteorite. Most mineral grains have homogeneous REEs, but show considerable inter-grain variations by a factor of 2 to 100. The whole rock REE abundances for Colomera, estimated by combining REE data with modal abundances, are relatively LREE-enriched with REEs of -10’CI, which suggest that Colomera silicates were highly differentiated and might represent a low degree partial melt (-10%) of a chondritic source. REE geochemistry of Colomera silicate inclusions points to an origin that involves differentiation, dynamic mixing, remelting, reduction, recrystallization, and subsequent rapid cooling near the surface of a planetary body.

关键词： ion probe rare earth elements Colomera silicate inclusions ⅡE iron meteorites

A New Palynological Assemblage from the Nenjiang Formation of Dayangshu Basin, and its geological Implication

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Acta Geologica Sinica(English Edition) 2020年第1期94卷 198-199页

作者： SUN Lei WANG Chenglong BIAN Xiongfei Shenyang Center of geological Survey China Geological SurveyShenyang 110034LiaoningChina School of Earth Sciences Northeast Petroleum UniversityDaqing 163318HeilongjiangChina

Objective The Dayangshu Basin located in eastern Inner Mongolia,is one of the key areas for oil and gas exploration in the periphery of Songliao *** far,this basin has been poorly explored,and the basic geological research is still weak,due to the lack of high-quality paleontologic and stratigraphic *** previous oil and gas investigations were mainly focused on the Early Cretaceous ***,the Late Cretaceous Nenjiang Formation in the basin also has hydrocarbon potential according to the latest *** recent oil and gas geological survey,palynological fossils have been discovered from the Nenjiang Formation in the Dayangshu Basin,providing new evidence for biostratigraphic division and correlation.

关键词： and its geological Implication A New Palynological Assemblage from the Nenjiang Formation of Dayangshu Basin

In situ SIMS oxygen isotope analyses: Evidence for the formation of aluminum-rich chondrules from ordinary chondrites

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Science China Earth Sciences 2015年第9期58卷 1748-1757页

作者： JIANG Yun HSU WeiBiao GUAN YunBin WANG Ying Key Laboratory of Planetary Sciences Purple Mountain Observatory Chinese Academy of Sciences division of geological and Planetary Sciences California Institute of Technology

Aluminum-rich chondrules （ARCs）, which share mineralogic and chemical properties with both Ca, Al-rich inclusions （CAIs） and ferromagnesian chondrules, play an important role in revealing their temporal and petrogenetic relationships. In this work, seven ARCs were found in three ordinary chondrites GRV 022410 （H4）, GRV 052722 （H3.7） and Julesburg （L3.6）. They contain bulk Al2O3 - 17%-33% and exhibit igneous textures composed of olivine, high- and low-Ca pyroxene, plagioclase, spinel and glass. In situ SIMS analyses show that ARCs have oxygen isotopic compositions （δ18O=-6.1‰-7.1‰; δ17O= -4.5‰-5.1‰） close to ferromagnesian chondrules but far more depleted in 160 than CAIs （δ18O=-40‰; δ17O=-40‰）. Most ARCs plot close to the terrestrial mass fractionation （TF） line, and a few between the TF and carbonaceous chondrite anhydrous mixing （CCAM） lines. Plagioclase, nepheline and glass suffered O-isotopic exchanges during the metamorphism processes in the parent body. Spinel, olivine and pyroxene represent the primary O-isotopic compositions of ARCs, and define a fitted line with a slope of- 0.7±0.1. Compared with the results of previous studies, shallower slope as well as more depleted 160 compositions further demonstrates that ARCs in ordinary chondrites are not a simple mixing product of ferromagnesian chondrules and CAIs. Instead, they probably experienced higher-degree oxygen isotope exchange with a δ6O-poor nebular gas reservoir during multiple melting episodes.

关键词： O-isotope SIMS Al-rich chondrule ordinary chondrite Antarctic meteorite

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Lateral bearing characteristics of subsea wellhead assembly in the hydrate trial production engineering

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China Geology 2023年第3期6卷 455-465页

作者： Jing Zeng Wen-wei Xie Bei-bei Kou Jing-an Lu Xing-chen Li De-jun Cai Hao-xian Shi Ke-wei Zhang Hua-qing Liu Jin Li Bo Li Guangzhou Marine geological Survey China Geological SurveyMinistry of Natural ResourcesGuangzhou 510075China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China National Engineering Research Center of Gas Hydrate Exploration and Development China Geological SurveyMinistry of Natural ResourcesGuangzhou 510075China Drilling Engineering division Offshore Engineering Company LimitedCNPCTianjin 300280China

Conductor and suction anchor are the key equipment providing bearing capacity in the field of deep-water drilling or offshore engineering,which have the advantages of high operation efficiency and short construction *** order to drill a horizontal well in the shallow hydrate reservoir in the deep water,the suction anchor wellhead assembly is employed to undertake the main vertical bearing capacity in the second round of hydrate trial production project,so as to reduce the conductor running depth and heighten the kick-off point ***,the deformation law of the deep-water suction anchor wellhead assembly under the moving load of the riser is not clear,and it is necessary to understand the lateral bearing characteristics to guide the design of its structural *** on 3D solid finite element method,the solid finite element model of the suction anchor wellhead assembly is *** the model,the seabed soil is divided into seven layers,the contact between the wellhead assembly and the soil is simulated,and the vertical load and bending moment are applied to the wellhead node to simulate the riser movement when working in the deep *** lateral bearing stability of conventional wellhead assembly and suction anchor wellhead assembly under the influence of wellhead load is *** analysis results show that the bending moment is the main factor affecting the lateral deformation of the wellhead string;the anti-bending performance from increasing the outer conductor diameter is better than that from increasing the conductor wall thickness;for the subsea wellhead,the suction anchor obviously improves the lateral bearing capacity and reduces the lateral *** conduct of the suction anchor wellhead assembly still needs to be lowered to a certain depth that below the maximum disturbed depth to ensure the lateral bearing stability,Thus,a method for the minimum conductor running depth for the suction anchor wellhead assembly is devel

关键词： Natural gas hydrate Deep-water Subsea wellhead Suction anchor Wellhead stability 3D solid finite element method Hydrate trial exploration engineering Natural gas hydrate trial production Shenhu area The South China Sea

Aerosol-Cloud-Precipitation Interactions in a Closed-cell and Non-homogenous MBL Stratocumulus Cloud

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Advances in Atmospheric Sciences 2022年第12期39卷 2107-2123页

作者： Xiaojian ZHENG Xiquan DONG Dale MWARD Baike XI Peng WU Yuan WANG Department of Hydrology and Atmospheric Sciences University of ArizonaTucson 85721AZUSA Pacific Northwest National Laboratory Richland 99354WAUSA division of geological and Planetary Sciences California Institute of TechnologyPasadena 91125CAUSA

A closed-cell marine stratocumulus case during the Aerosol and Cloud Experiments in the Eastern North Atlantic(ACE-ENA)aircraft field campaign is selected to examine the heterogeneities of cloud and drizzle microphysical properties and the aerosol-cloud-precipitation *** spatial and vertical variabilities of cloud and drizzle microphysics are found in two different sets of flight legs:Leg-1 and Leg-2,which are parallel and perpendicular to the cloud propagation,*** cloud along Leg-2 was close to adiabatic,where cloud-droplet effective radius and liquid water content linearly increase from cloud base to cloud top with less *** cloud along Leg-1 was sub-adiabatic with lower clouddroplet number concentration and larger cloud-droplet effective,but higher drizzle droplet number concentration,larger drizzle droplet median diameter and drizzle liquid water *** heavier drizzle frequency and intensity on Leg-1 were enhanced by the collision-coalescence processes within cloud due to strong *** sub-cloud precipitation rate on Leg-1 was significantly higher than that along *** a result,the sub-cloud accumulation mode aerosols and CCN on Leg-1 were depleted,but the coarse model aerosols *** further leads to a counter-intuitive phenomenon that the CCN is less than cloud-droplet number concentration for *** average CCN loss rates are −3.89 cm^(-3)h^(-1)and −0.77 cm^(-3)h^(-1) on Leg-1 and Leg-2,*** cloud and drizzle heterogeneities inside the same stratocumulus can significantly alter the sub-cloud aerosols and CCN *** it should be treated with caution in the aircraft assessment of aerosol-cloud-precipitation interactions.

关键词： maritime aerosol cloud and drizzle properties coalescence-scavenging effect of the sub-cloud aerosol and CCN and aerosol-cloud-precipitation interactions

Lithofacies Characters and Significance of the Submarine Fan of the Liufengguan Group in Qinling

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Acta Geologica Sinica(English Edition) 2012年第1期86卷 174-188页

作者： ZHENG Ning LI Tingdong YOU Guoqing ZHANG Shuanhou CUI Jiantang CHENG Muwei Institute of Geology Chinese Academy of Geological SciencesBeijing 100037China Shaanxi Institute of geological Survey Xi'an 710065ShaanxiChina Research Institute of Petroleum Exploration and Development Beijing 100083China

Field investigation and laboratory research on flysch of the Liufengguan Group in Qinling indicate the following：（1） Sandstone of the Liufengguan Group is categorized as feldspathic lithic graywacke with a minor amount of lithic graywacke in the QFR triangular diagram. Grain size〈0.3 mm. Bedding plane structures such as groove casts and suspected flute casts can be found at the bottom of the sandstone. It is inferred that currents may have come from the southeast during deposition. Bedding structures such as ripple marks, graded bedding, parallel bedding, small-scale cross bedding, climbing bedding, suspected convolute bedding, microlamination and sliding structures have also been observed, which are of indicative significance. It is thought that the Liufengguan Group has the sedimentary characteristics of bedding, bedding plane structures and lithologicai assemblages of deep-sea low-density turbidity current deposits. The vertical succession of the Bouma sequence in the inner fan subfacies zone is generally incomplete： the assemblage of Ta and Tabc is commonly seen; the succession of the middle fan subfacies zone is relatively complete; and divisions Te and Tb are common in the outer fan subfacies zone. （2） The flysh of the Liufengguan Group is a sequence of deep-sea argillaceous-arenaceous submarine fan deposits, in which the authors recognize the inner, middle and outer fan subfacies and also nine types of lithofacies： normal graded sandstone （A1）, medium- to thick-bedded, fine-grained sandstone （A2）, medium- to thick-bedded and massive siltstone （A3）, thin-bedded, fine-grained sandstone and mudstone （B1）, irregular interbeds of thinbedded, fine-grained sandstone and siltstone （B2）, thin-bedded, fine-grained sandstone （C1）, very thin-bedded, fine-grained sandstone （D1）, olistostromes （El） anddeep-sea mudstone （F）. The inner fan consists of four microfacies： natural levee （A1）, water channel （A2, A3） and olistostrome （El）; in the middle fan there also occur four

关键词： Liufengguan Group flysh lithofacies low-density turbidity current submarine fan