Seismic Imaging and 3D Architecture of Yongle Atoll of the Xisha Archipelago, South China Sea

Yongle atoll in the Xisha(Paracel) Archipelago is an isolated carbonate platform developed on Precambrian metamorphic and Mesozoic volcanic rocks since the early Miocene. To identify the 3D stratigraphic architecture and evolution of this platform, 13 high-resolution seismic profiles and shallow-to-deep water multi-beam data were processed and analyzed to reveal seismic facies, sequence boundary reflectors, seismic units, and platform architecture. Nine types of seismic facies were recognized based on their geometry, which included seismic amplitude, continuity, and termination patterns;additionally, six reflections, i.e., Tg, T60, T50, T40, T30, and T20, were identified in the Cenozoic strata. Five seismic units, SQ1(lower Miocene), SQ2(middle Miocene), SQ3(upper Miocene), SQ4(Pliocene), and SQ5(Quaternary), were identified from bottom to top across the platform. The platform grew rapidly in the middle Miocene and backstepped in the late Miocene–Pliocene. Here, we discuss the developmental characteristics and evolution of the Yongle Atoll, in combination with drilling wells, which can be divided into four stages: the initiation stage in the early Miocene, the flourishing stage in the middle Miocene, the partial-drowning stage in the late Miocene–Pliocene, and modern atoll in the Quaternary.

Initiation and evolution of the South China Sea: an overview

Different models have been proposed for the formation and tectonic evolution of the South China Sea （SCS）, including extrusion of the Indochina Peninsula, backarc extension, two-stage opening, proto-SCS dragging, extension induced by a mantle plume, and integrated models that combine diverse factors. Among these, the extrusion model has gained the most attention. Based on simplified physical experiments, this model proposes that collision between the Indian and Eurasian Plates resulted in extrusion of the Indochina Peninsula, which in turn led to opening of the SCS. The extrusion of the Indochina Peninsula, however, should have led to preferential open- ing in the west side of the SCS, which is contrary to observations. Extensional models propose that the SCS was a backarc basin, rifted off the South China Block. Most of the backarc extension models, however, are not compatible with observations in terms of either age or subduction direction. The two-stage extension model is based on extensional basins surrounding the SCS. Recent dating results indeed show two-stage opening in the SCS, but the Southwest Subbasin of the SCS is much younger, which contradicts the two-stage extension model. Here we pro- pose a refined backarc extension model. There was a wide Neotethys Ocean between the Australian and Eurasian Plates before the Indian-Eurasian collision. The ocean floorstarted to subduct northward at ~ 125 Ma, causing backarc extension along the southem margin of the Eurasian Plate and the formation of the proto-SCS. The Neotethys sub- duction regime changed due to ridge subduction in the Late Cretaceous, resulting in fold-belts, uplifting, erosion, and widespread unconformities. It may also have led to the subduction of the proto-SCS. Flat subduction of the ridge may have reached further north and resulted in another backarc extension that formed the SCS. The rollback of the fiat subducting slab might have occurred ~ 90 Ma ago; the second backarc extension may have initiated between 50 and 45 Ma. The opening of the Southwest Subbasin is roughly simultaneous with a ridge jump in the East Sub- basin, which implies major tectonic changes in the sur- rounding regions, likely related to major changes in the extrusion of the Indochina Peninsula.

TEM investigations of South Atlantic Ridge 13.2°S hydrothermal area

According to the exploration contract about polymetallic sulfides in the SWIR （Southwest Indian Ridge） signed by China with the International Seabed Authority, to delineate sulfide minerals and estimate resource quantity are urgent tasks. We independently developed our first coincident loop Transient Electromagnetic Method （TEM） device in 2010, and gained the TEM data for seafloor sulfide at South Atlantic Ridge 13.2°S in June 2011. In contrast with the widely applied CSEM （Marine controlled-source electromagnetic） method, whose goal is to explore hydrocarbons （oil/gas） of higher resistivity than seawater from 102 to 103 m below the sea floor, the TEM is for low resistivity minerals, and the target depth is from 0 to 100 m below the sea floor. Based on the development of complex sulfide geoelectrial models, this paper analyzed the TEM data obtained, proposing a new method for seafloor sulfide detection. We present the preliminary trial results, in the form of apparent resistivity sections for both half-space and full-space conditions. The results cor- respond well with the observations of the actual hydrothermal vent area, and the detection depth reached 50-100m below the bed, which verified the capability of the equipment.

Abundance and Distribution of Fatty Acids in Sediments of the South Mid-Atlantic Ridge

Sediment samples obtained from the South Mid-Atlantic Ridge were studies by gas chromatography-mass spectrometer （GC-MS） for the abundance and distributions of total fatty acids （TFAs）. Approximately 34 fatty acids were identified, with the chain-lengths ranging from C12 to C30. The total concentrations of TFAs （∑TFA） ranged from 7.15 to 30.09 μgg-l dry sediment, and ∑TFA was weakly correlated with bitumen content （R2=0.69）. The ∑TFA of samples around hydrothermal areas were significantly higher than that of samples away from hydrothermal areas, indicating intense primary production and large biomass in the hydro- thermal areas, and suggesting a close relationship between hydrothermal activity and ∑TFA of samples. The characteristics of the TFA composition in the present study are rich in monounsaturated fatty acids and lacking in polyunsaturated fatty acids, and the ra- tios between the concentrations of monounsaturated fatty acids and ∑TFAs in samples close to the hydrothermal areas, are about 0.8, but for samples far from the hydrothermal areas, they are only about 0.5. Several fatty acids （e.g., a/iC15：0 and C16：1co7）, which are signature biomarkers for sulfur-metabolizing bacteria, show the same distribution trend as ∑TFA of samples, further highlighting the close relationship between fatty acid content and hydrothermal activity and/or hydrothermal communities. The metabolic activities of hydrothermal communities, especially those of microorganisms, are likely the main source of fatty acids in samples.

Component characteristics of polycyclic aromatic compounds in sediments of the South Mid-Atlantic Ridge

10 samples of sediments obtained from the South Mid-Atlantic Ridge were measured for the abundances and distributions of polycyclic aromatic compounds（PAHs）. The total concentrations of PAHs（∑PAHs） ranged from 2.768 to 9.826 μg/g dry sediment. The ∑PAHs was higher in sample 22V-TVG10 and sample 26V-TVG05 which were close to hydrothermal fields, with the lowest value in sample 22V-TVG14 which was farthest from hydrothermal fields, suggesting a probable hydrothermal origin of ∑PAHs of samples. Approximately nine kinds of PAHs were identified, and low molecular mass tricyclic and tetracyclic aromatic compounds were predominant in the samples. The concentrations of fluoranthene which were typical as hydrothermal alteration compounds were the highest among PAHs with dry weight between 0.913–3.157 μg/g. The phenanthrene homologue was most abundant in the samples, and the ratios between parent phenanthrene and methylphenanthrene which probably reflected the degree of hydrothermal alteration ranged from 0.097 to 1.602. The sample 22V-TVG10 possessing a maximum ratio value showed the intense influence of the hydrothermal alteration on this sample, which might further imply that PAHs in sediments were mainly derived from the hydrothermal alteration.

Mathematical model of wave transformation over radial sand ridge field on continental shelf of South Yellow Sea

According to a deformed mild-slope equation derived by Guang-wen Hong and an enhanced numerical method, a wave refraction-diffraction nonlinear mathematical model that takes tidal level change and the high-order bathymetry factor into account has been developed. The deformed mild-slope equation is used to eliminate the restriction of wave length on calculation steps. Using the hard disk to record data during the calculation process, the enhanced numerical method can save computer memory space to a certain extent, so that a large-scale sea area can be calculated with high-resolution grids. This model was applied to wave field integral calculation over a radial sand ridge field in the South Yellow Sea. The results demonstrate some features of the wave field： （1） the wave-height contour lines are arc-shaped near the shore; （2） waves break many times when they propagate toward the shore; （3） wave field characteristics on the northern and southern sides of Huangshayang are different; and （4） the characteristics of wave distribution match the terrain features. The application of this model in the region of the radial sand ridge field suggests that it is a feasible way to analyze wave refraction-diffraction effects under natural sea conditions.

The distribution and composition of hydrocarbons in sediments of the South Mid-Atlantic Ridge

Sediment samples obtained from the South Mid-Atlantic Ridge are analyzed by a gas chromatography-mass spectrometer（GC-MS） for the abundances and distributions of hydrocarbons. The hydrocarbons in the samples exhibit a bimodal distribution of n-alkanes and are rich in 3-methylalkanes, 8-methylalkanes and 2, 4,（n-1）-trimethylalkanes, which may be the result of metabolic activity of benthic microorganism. Terpanes, hopanes and steranes are all enriched in the samples, which also support the microbial origin of hydrocarbons in samples.Bitumen and hydrocarbons in the samples show a trend that the contents are the highest in the Samples 22V-TVG10 and 26V-TVG05 collected near hydrothermal areas, and the lowest in samples 22IV-TVG01, 22V-TVG11,and 22V-TVG14 collected far from the hydrothermal areas, which suggest the possible influence on the samples by hydrothermal activity.

On Characteristics and Cultures of the Hakka's Enclosed Houses in South Jiangxi Province

General situation and distribution of round houses of the Hakka in south Jiangxi were introduced, such architectural styles as enclosed house with a square yard (kouzi wei, in the shape of 口), enclosed house with a yard of three transverse and one longitudinal constructions (guozi wei, in the shape of 国), and enclosed house with a round house in its yard (tao wei) were taken to analyze features of the Hakka's enclosed houses. It was highlighted that the Hakka's enclosed houses in south Jiangxi has diversified architectural styles and outstanding defensive and living functions. Construction art and religious culture shown by the enclosed houses were interpreted, and the branch of Han people with unique dialects, cultures, folk customs and emotional attitudes was proposed as a miniature of the culture in south Jiangxi. Moreover, it was stressed that more attention of the public and more efforts for the protection should be given to the Hakka's cultures in south Jiangxi, carriers of the locals' history over the past thousands of years.

An Anomalous Seamount on the Southwestern Mid-Ridge of the South China Sea

Objective The development of continental rifting and seafloor spreading can be predominated by magmatic upwelling （magma-rich） or tectonic stretching （magma-poor）. Located in the terminal portion of propagating seafloor spreading of the South China Sea （SCS）, the southwestern mid-ridge of the southwest sub-basin （SWSB） of the SCS was found with much thin crust and numerous faulted blocks coupling with magma-poor continental margins along its flanks. Therefore, the southwestern part of the SWSB is most likely to be a tectonic-dominated basin. To justify the hypothesis with further evidence, we investigated the nature of seamounts on the southwestern mid-ridge of the SWSB which may inherit seafloor spreading.

Clay mineral distribution characteristics of surface sediments in the South Mid-Atlantic Ridge

Clay minerals are usually considered as important indicators to identify sources in both terrigenous and marine sediments.In particular,clay minerals in metalliferous sediments(MS)have long been studied in global oceans except in South Mid-Atlantic Ridge(SMAR)due to limited explorations.Thus,32 MS and 34 non-MS(NMS)samples were analyzed to clarify the distribution characteristics and mineral compositions of clay minerals.All the sediments were collected along the SMAR between 12°S and 27°S.After removal of organic matter and carbonate,clay fractions(<2μm)were investigated by Xray diffraction(XRD)analysis.Results show that clay mineral assemblages of surface MS consist dominantly of smectite,less abundant illite,chlorite,and kaolinite in average weight percentage of 30%,21%,18%,and 16%,respectively.On the other hand,clay mineral assemblages in the NMS consist mainly of illite,less abundant kaolinite,chlorite,and very scarce smectite in average weight percentage of 47%,29%,24%,and 0.2%,respectively.The clay fractions in MS are mainly composed of amorphous or poorly crystallized Fe/Mn oxyhydroxides,clay mineral,quartz,and plagioclase.However,the counterparts in the NMS are mainly composed of well-crystallized clay minerals,quartz,and plagioclase without the presence of Fe/Mn oxyhydroxides.It is suggested that most of the illite,kaolinite,and chlorite in both MS and NMS are likely aeolian dust in origin from South Africa continent.In addition,the abundance of kaolinite dominates the clay mineral assemblage at low latitudes,where the intensive chemical weathering of continental source rocks facilitating the formation of kaolinite.In terms of smectite,it is indicated of authigenic origin in consideration of only smectite is available in several MS and the absence in NMS.Moreover,the MS samples with only smectite available are always accompanied by goethite.Therefore,it is assumed that most of smectite occurred in studied area is the results of interaction between hydrothermal Fe-oxyhydroxide,silica,and seawater.

Looking towards the Future of BIM in South Korea Towards AI-Enhanced BIM

This paper provides an overview of South Korea’s 20-year journey in adopting building information modeling(BIM) and future direction. It first discusses the six phases of BIM adoption in South Korea, starting from the use of BIM as a marketing tool to its current intelligent BIM phase. The government’s support for BIM-related research and development projects is also highlighted, with a focus on the artificail intelligence (AI)-based architectural design automation project. As the future direction, it explores the integration of AI with BIM in both local and global contexts. The paper presents AIpowered architectural design methods, including AI-powered early architectural design generation and architectural detailing.Compared to AI-based early architectural design generation, architectural detailing is an unexplored research topic. This paper introduces two AI-and BIM-based architectural detailing methods, being developed at Yonsei University:namely,BIM library transplant and Natural language-based Architectural Detailing through Interaction with AI (NADIA). These methods demonstrate how AI-enhanced BIM can enable architects to interactively develop building details using a language model as a conversational AI and a knowledge base, and a BIM authoring tool as a design platform, in the near future.

Petrology and geochemistry of South Mid-Atlantic Ridge(19°S) lava flows:Implications for magmatic processes and possible plume-ridge interactions

The South Mid-Atlantic Ridge(SMAR)19°S segment,approximately located along the line of Saint Helena volcanic chain(created by Saint Helena mantle plume),is an ideal place to investigate the issue whether the ridgehotpot interaction process affected the whole MAR.In this study,we present major and trace elemental compositions and Sr-Nd-Pb isotopic ratios of twenty fresh lava samples concentrated in a relatively small area in the SMAR 19°S segment.Major oxides compositions show that all samples are tholeiite.Low contents of compatible trace elements(e.g.,Ni=239-594 ppm and Cr=456-1010 ppm)and low Fe/Mn(54-67)and Ce/Yb(0.65-1.5)ratios of these lavas show that their parental magmas are partially melted by a spinel lherzolite mantle source.Using software PRIMELT3,this study obtained mantle potential temperatures(Tp)beneath the segment of1321-1348℃,which is lower relative to those ridges influenced by mantle plumes.The asthenospheric mantle beneath the SMAR 19°S segment starts melting at a depth of^63 km and ceases melting at^43 km with a final melting temperature of^1265℃.The extent of partial melting is up to 16%-17.6%with an average adiabatic decompression value of 2.6%/kbar.The correlations of major oxides(CaO/Al2 O3)and trace elements(Cr,Co,V)with MgO and Zr show that the parental magma experienced olivine and plagioclase fractional crystallization during its ascent to the surface.87Sr/86Sr(0.702398-0.702996),143 Nd/144 Nd(0.513017-0.513177)and 206Pb/204Pb(18.444-19.477)ratios of these lavas indicate the mantle source beneath the SMAR 19°S segment is composed of a three-component mixture of depleted MORB mantle,PREMA mantle,and HIMU mantle materials.The simple,binary mixing results among components from plume-free SMAR MORB,Saint Helena plume and Tristan plume show that asthenospheric mantle beneath the SMAR 19°S segment may be polluted by both Saint Helena and Tristan plume enriched materials.The abovementioned mantle potential temperatures,together with the low Saint Helena(<10%)and Tristan(<5%)components remaining in the asthenospheric mantle at present,show that the physically ridge-hotspot interactions at SMAR 19°S segment may have ceased.However,the trace element and SrNd-Pb isotopically binary mixing calculation results imply that these lavas tapped some enriched pockets left when Saint Helena and/or Tristan plume were once on the SMAR during earlier Atlantic rifted history.

三角洲砂体构型对水驱波及特征的影响——以南图尔盖盆地Kumkol South油田J-Ⅱ层为例

以哈萨克斯坦南图尔盖盆地Kumkol South油田上侏罗统J-Ⅱ层为例,运用砂体精细表征、水淹层综合解释、产吸剖面统计分析和油藏数值模拟方法,研究了三角洲砂体构型特征及其非均质性,明确了砂体构型对水驱波及特征的影响。研究结果表明,三角洲砂体构型特征复杂,为泥岩隔层和泥质夹层发育的"镶嵌式"构型模式,砂体构型特征控制其水驱波及特征:三角洲各单砂体之间由于非渗透或弱渗透边界、水下分流间湾泥岩的侧向或垂向遮挡,砂体叠置结构特征复杂,注入水优先流向物性较好的水下分流河道和河口坝砂体,致使这两类砂体水淹作用强,采出程度高,水驱平面波及效果好;单砂体内部,水下分流河道和河口坝单砂体一方面由于内部发育泥质夹层,对注入水具有纵向阻挡和分流作用,砂体纵向动用程度高,水驱波及效果好,另一方面由于单砂体内渗透率级差大,水驱优势通道发育程度高,水驱波及不均匀,而侧缘席状砂为均质薄层细粒砂,物性差,水淹均匀,水驱波及效果差。

砂体构型特征与剩余油分布模式——以哈萨克斯坦南图尔盖盆地Kumkol South油田为例

以哈萨克斯坦南图尔盖盆地Kumkol South油田为例,通过对曲流河、辫状河和三角洲砂体构型特征、开发效果、剩余油分布特征的对比研究,提出了不同类型砂体构型特征对剩余油分布的控制模式。辫状河砂体构型特征简单,为近水平泥质夹层分布的"泛连通体"构型模式,水驱波及较均匀,边底水推进快,高含水期剩余油分布模式为近水平的泥质落淤层"垂向遮挡控油模式";曲流河砂体构型特征为废弃河道和点坝内泥质侧积层的"半连通体"构型模式,注入水主要沿砂体中下部波及,高含水期剩余油分布模式为废弃河道和泥质侧积层"侧向遮挡控油模式";三角洲砂体构型特征复杂,为侧向与垂向泥岩隔层和泥质夹层发育的"镶嵌式"构型模式,注入水主要沿水流优势通道波及,波及程度相对较弱,高含水期剩余油分布模式为泥岩隔层和泥质夹层的"复合遮挡控油模式"。不同类型砂体剩余油分布规律不同,应采取针对性措施进行剩余油挖潜。

基于川南建筑特色的会馆室内装饰设计研究——以夕佳山民居为例

以夕佳山民居为代表的川南建筑具有独特的地域特色,其装饰元素往往具有平安吉祥、多福健康等美好寓意,代表着人们对美好生活的向往。对其地域文化和建筑艺术特征进行了分析叙述,将具有地域特色的夕佳山传统民居建筑元素和会馆室内设计相结合,从形、色、材几个方面进行装饰方法探讨。在设计应用中,根据会馆的文化属性,从消费者的实际需求出发,注重不脱离装饰外形所依附的内在文化和内在精神价值,利用新材料新技术作为突破点,以传承和创新两个方向探讨结合的设计策略,在会馆室内设计中传承创新川南地域文化。

基于STIRPAT模型的山东省居住建筑运行碳排放影响因素研究

为有效实施建筑领域节能减排,实现双碳目标,以2005-2021年山东省居住建筑运行阶段碳排放数据为研究对象,利用STIRPAT模型对人口数量、人均GDP、人均消费支出、人均可支配收入、城镇化水平、居住建筑面积、单位建筑面积能耗、能源消耗强度和能源结构等影响碳排放的因素进行岭回归分析。结果表明:人口数量、人均GDP、人均消费支出、人均可支配收入、城镇化水平、居住建筑面积、单位建筑面积能耗和能源消耗强度等的增加会促使碳排放量的增加,但能源结构的增加会抑制碳排放量的增加,其中人口数量是影响碳排放的关键因素。据此提出山东省居住建筑节能减排的建议和对策。

现代主义的“再国族化”探索——南亚国家独立初期现代主义建筑的当代危机与应对

近年来,南亚多个现代主义建筑的标志性项目面临被改造甚至拆除的危机。这些建筑建于南亚各国独立初期,其现代主义风格承载了当时强调去殖民化、追求工业化与现代化的国族叙事。然而从20世纪后期开始,随着国族叙事从“公民式”向“民族式”转变,现代主义建筑逐渐“祛魅”,不再是国族身份认同的象征,又未能融入遗产保护的话语体系之中,不得不在年久失修后为发展让路,面临危机。对此,南亚建筑师们试图建立一种新的叙事,将这些建筑诠释为现代主义适应南亚各国独立初期特定语境的结果,是追求变革与进步的理想和社会经济发展初期阶段的现实之间的联结,从而将其“再国族化”,为这些建筑的保护提供合理性论证。

利用洋中脊玄武岩中橄榄石斑晶制约南海打开的地幔动力学机制

地幔柱与板块构造是地球运行的两大基本动力学机制。南海及其周缘地区处于海南地幔柱与东南亚环形俯冲系统时空交汇的背景,而新生代地幔柱在南海形成演化过程中所扮演的角色存在颇多争议。地幔源区富含辉石岩是南海及其周缘与地幔柱活动相关的玄武岩的共有特征,基于此推测,本文利用国际大洋发现计划(IODP)367航次在南海北缘U1500B站位钻遇的南海扩张初期洋中脊玄武岩(MORB)的橄榄石成分来制约南海扩张初期的地幔岩性,以检验南海扩张初期是否存在地幔柱-洋脊叠加。U1500B MORB所含橄榄石斑晶的Fo=76.4~89.4,NiO=0.09%~0.26%,CaO=0.25%~0.34%,MnO=0.16%~0.33%。这些橄榄石斑晶具有与南海西南次海盆扩张末期U1433B钻孔的MORB以及全球其他开放大洋MORB相似的NiO、CaO、MnO含量和FeO/MnO比值,代表其源区岩性主要为橄榄岩。U1500B钻孔MORB与该区存在地幔柱叠加的基性岩浆所含橄榄石斑晶成分的差异显著,表明南海扩张初期不存在地幔柱叠加,与前人估计的U1500B洋中脊玄武岩的正常地幔潜能温度(~1380℃)相符合。由于南海扩张初期洋中脊岩浆产率高,但缺乏地幔热异常和易融组分如辉石岩等,推测其地幔中可能有较多的早前俯冲板片贡献的再循环挥发分来维持高岩浆产率。所以,俯冲板片后撤导致的岩石圈伸展可能是南海打开的主要动力学机制。

南海洋脊跃迁的深地震探测数据分析

洋脊跃迁事件是海底扩张阶段受强烈构造和岩浆作用的普遍现象,地球物理资料表明洋脊跃迁事件存在于南海多期次海底扩张过程中,然而关于洋脊跃迁的深部速度结构特征尚不清楚.2021年国家自然科学基金共享航次实施了深地震探测测线OBS2021-1,该测线横穿南海东部次海盆洋脊跃迁(J3)区域.本文介绍了该测线数据的采集情况,完成了导航文件(Ukooa文件)的制作、原始数据的格式转换、炮点位置和海底地震仪(OBS)位置校正的前期数据处理工作.结果表明,OBS2021-1测线数据质量良好,经过炮点和OBS位置校正后,OBS综合地震记录剖面可识别出多组清晰的P波震相,包括Pw、Pg、PmP以及Pn震相.根据同船采集的多道地震处理解释和国际大洋发现计划(IODP)钻探数据,建立了沿测线的初始速度模型.使用RayInvr软件初步获得了OBS2021-1测线下方的正演速度结构模型,识别洋脊跃迁的深部速度结构特征.数据处理结果表明南海洋脊跃迁的地壳厚度增厚,在多道地震剖面上存在渐新世地层的缺失,为进一步研究南海洋脊跃迁过程与构建南海形成演化历史奠定了研究基础.

中国古代园林观月空间“景月同构”设计探析——以明清园林为例

经“月岩望月”研究发现,南宋时期已出现符合天文运行规律、“朝对东-南”的观月景观营建,构景手法表现为月景与地景的同框因借,展现了中国古代园林“景月同构”的空间营造特征。在“景月同构”是否能作为中国古代园林月景设计范式,以及其“朝对东-南”的设计具有哪些共性特征2个问题的导向下,基于古代园林遗存和园记等材料进行统计、筛选,针对观月空间布局与构景要素进行整理。总结出明清园林中成功观月的景点普遍存在“朝对东-南”的方向性特点,并归纳出“有水为宜”“丘壑应变”“景题点睛”“旱园水作”4类中国古代园林观月空间的“景月同构”设计范式。进一步探讨了中国传统园林在月景营建中对天文规律的应用,以期为古代园林观月景点复原定位及现代月景设计在山水地形营造、景观元素布局和观月氛围设计方面提供理论指导。