柴达木盆地新生代沉积转移及其动力学意义

新生代柴达木盆地的坳陷、沉积作用和周缘山体隆升存在着很好的耦合关系,沉积中心位置、沉积范围大小及沉积中心的平面形态有规律的变化,反映出新生代柴达木盆地承受过来自北缘祁连山方向、西北缘阿尔金山方向以及南缘昆仑山方向三组挤压应力的作用,其中来自阿尔金山方向的应力一直在持续发挥作用;来自盆地南北缘的应力也始终发挥重要作用,同时经历了一个由北东向(古近纪早—中期)→北北东向(古近纪末期—中新世早期)→近南北向(中新世中期—上新世中期)→北东向(上新世晚期)的转向过程。在此基础上建立了柴达木盆地新生代发展演化模式,提出柴达木盆地新生代经历了由北向南挤压—旋转、由南西向北东挤压—旋转以及由向北挤压—旋转的动力学演化过程。     

长江经济带城乡一体化对能源效率的空间效应分析

城乡一体化作为新的经济增长动能,是建设高效的能源经济体系、平衡经济社会发展与生态环境保护的关键性途径。因此城乡一体化对能源效率的效应分析成为促进经济社会可持续发展的重要课题。本文以长江经济带各省市为研究对象,采用DEA测度了考虑非期望产出的能源效率值,并分析其时空上的分异特征,通过构建经济、社会和基础设施3个维度的综合指标体系评价城乡一体化水平,以此为基础运用Moran's I指数确定了能源效率、城乡一体化水平及其他影响因素的空间相关性,最后运用混合地理加权回归估计城乡一体化及3个控制变量的回归参数值并作空间效应分析。得出结论:① 从空间相关性分析来看,长江经济带的城乡一体化发展水平对能源效率具有正向作用,同时经济发展水平和产业结构也对能源效率有正向影响,而技术进步则在一定条件下与能源效率呈负相关关系;② 从回归系数的估计值来看,城乡一体化对能源效率的影响程度要小于技术进步和产业结构,而经济发展水平对能源效率的影响程度最小;③ 城乡一体化水平对能源效率的正向影响程度随着能源效率的上升呈现出先上升后下降的趋势,并且其影响在空间分布上自东向西呈现出递增的特征;④ 长江经济带的能源效率呈现显著的空间相关性和空间异质性。基于此,对长江经济带推进城乡一体化进程中的能源效率提升具有重要意义。     

基于多源时空大数据的区际迁徙人群多层次空间分布估算模型——以COVID-19疫情期间自武汉迁出人群为例

已有研究很少关注区际迁徙人群在不同尺度上空间分布的动态估算问题。COVID-19疫情爆发以来,坚决防止疫情扩散成为社会最紧迫的事情。在2020年1月23日武汉“封城”前夕,已有500多 万人离开了武汉,快速准确地推算这部分人群的去向,可以为防止疫情扩散和制定防疫决策提供科学依据。本文以此为例,基于开源腾讯位置请求大数据、百度迁徙大数据、土地覆盖数据等多源地理时空大数据,提出一种区际迁徙人群多层次空间分布动态估算模型,用于推算2020年除夕 （2020年1月24日）之前从武汉流入湖北省内各地的人群数量及其分布特征。结果显示：① 春节时段湖北省各地级市农村地 区人群增加数量占人群变化总量的比例平均达124.7%,从武汉市迁入各地级市的人群中至少51.3%流入农村地区;② 区县尺 度人群变化总量的空间分布呈现3个圈层结构：第一圈层为疫情核心区,包括武汉及其周边地区,以人群流出为主;第二圈层为 重点关注区,包括黄冈、黄石、仙桃、天门、潜江、随州、襄阳,以及孝感、荆门、荆州和咸宁的部分地区,以人群总量和农村地区人 群数量大幅增加为主;第三圈层为次级关注区,包括湖北西部宜昌、恩施、神农架和荆门部分地区,以人群小幅流入为主。最后,建议湖北省内,尤其是位于第二圈层内的区县,应高度关注农村地区人群的疫情防控。此研究成果在2~3天完成,显示大数据是可以快速地响应重大公共安全事件,为决策的制定提供一定支持的。     

“一带一路”区域水电站工程生态环境影响遥感监测

为实现“一带一路”区域可持续发展,我国倡导绿色、低碳、循环、可持续的生产生活方式,建设绿色“一带一路”。遥感技术在生态环境监测与评价方面具有重要作用。本文以“一带一路”区域中国援建的水电站工程为研究对象,基于陆地系列卫星(Landsat)、哨兵2号（Sentinel-2）等遥感对地观测数据,利用决策树与缓冲区分析等方法,从水电站库区概况、水电站对植被生长状况与生态资源影响等方面,开展“一带一路”区域水电站项目建设对当地经济发展和生态环境影响的遥感监测及分析。本文首先根据遥感影像与DEM确定库区及库容,结合最小外接正方形面积比及平均宽度等指标确定各水电站缓冲区类型和范围。利用NDWI及NDVI构建决策树模型,提取各缓冲区土地利用类型,分为水体、林地、草地、耕地和其它5类;结合区域植被覆盖度,估算库区生态占用并对水电站建成前后的土地利用类型和植被变化进行分析。研究结果表明：① “一带一路”沿线10座水电站造成的生态损失与库区面积呈正相关,不同工程间,在水体、林地、草地、耕地和其它方面的损失面积大小存在较大差异;② 土地利用类型与植被覆盖度年均变化幅度约为0.35%、1.27%,水电站修建对周边生态资源与植被生长状况影响较小,同时在植被覆盖度较低的地区水电站的修建会明显改善周边环境;③ 各水电站周边的植被覆盖度差异较大,大部分水电站周边植被生长状况良好;④ 水电站建设始终坚持工程建设与环境保护并重,从施工设计到水电站后期维护期间,积极采取环保措施,减少占用,保护生物多样性,生态风险防范得当;⑤ 水电站提供了优质的清洁能源,促进了当地经济和社会发展。     

叠前深度域偏移成像技术及其应用

根据“西部煤炭资源高精度三维地震勘探技术”项目中对国内外各种深度域偏移成像方法和特点的调研成果．对各类深度域成像的算法和特点进行了总结,指出不同深度域成像算法选取原则主要依据构造复杂程度和横向速度变化情况。结合克希霍夫叠前三维深度域偏移模块说明深度域偏移原理和工作流程,并以实例说明叠前深度域成像能够解决因第四系地层厚度剧烈变化造成的下覆煤层赋存形态被扭曲、深度误差大、断层平面位置不准确等问题。该实例中,叠前深度域成像划分的煤层深度比时间域偏移剖面解释结果向下移动40多m,钻探结果证实其解释的煤层深度和断层位置比较准确。     

Sedimentary facies of the central part of radial tidal sand ridge system of the eastern China coast

A unique radial tidal sand ridge system (RTSRS) has developed under a complex tidal current field on the eastern China coast between the Yangtze River delta to the south and the abandoned Yellow River (Huanghe) delta to the north. The present study examines the sedimentary evolution of a ridge-channel pair in the central RTSRS. Three cores, with two on the ridges and one in the channel, were drilled to reveal the late Pleistocene-Holocene deposits of the system. Five sedimentary facies were distinguished, i.e. ridgeshallow subtidal facies, ridge-deep subtidal facies, nearsurface channel bottom facies, middle tidal flat facies and low tidal flat facies. The ridge-shallow subtidal facies consists of sandy strata with ripple cross beddings, horizontal lamina, and massive beddings. Bioturbation seldom occurs. The ridge-deep subtidal facies is primarily characterized by sandy and muddy interlayers with common flaser and lenticular bedding structures. Bioturbation appears abundantly. Massive and graded sediment sequences of storm origin are present as characterized by rich shell fragments. The nearsurface channel bottom facies consists of loose, soft, clayey silt deposits with deformed sedimentary layers. This facies occurs in the deeper part of the active channels. The middle tidal flat and lower tidal flat facies composed of silt-clay couplets prevailed primarily in the tidal flats. Incomplete sedimentary successions show that coastal plain deposits dominate in the study area during 12–13 ka B.P. The sandy ridge and channel facies became dominant during 4–6 ka B.P. when the sea level receded temporarily. Tidal ridge and channel in the study area became active during the last four decades. Sediment reworking due to typhoon and sandy ridge migration plays a key role in shaping the present radial ridge system.     

地震勘探在地层倾角较大地区的应用初探

在地层倾角较大地区,尤其是通过钻孔见煤深度推断的地层倾角变化较大地区,钻孔之间的地层及构造变化情况,若仅依靠钻孔资料,可能会得出与事实相反的结论。大倾角地层地区的地震勘探,须解决的地质问题主要有：受构造运动影响,煤系地层被风化剥蚀后,与新生界呈不不整合接触关系的煤层露头点：背斜轴部发育的褶曲、断层以及煤层赋存形态的变化;受大断层的牵引作用,其附近地层倾角变化及小断层的发育情况。在地震资料处理时,对干涉波应采用炮炮计算切除量及去线性干扰模块进行切除：并认为偏移处理中的层速度,做沿层平滑较均方根速度平滑更加合理。在进行解释时,应注意分辨不同的波形特征及断点识别标志。实例表明：地震勘探可以准确地控制单斜地层因断层导致的背斜构造及地层倾角变化情况。     

Diverse Range of Mineralization Induced by Phase Separation of Hydrothermal Fluid: Case Study of the Yonaguni Knoll IV Hydrothermal Field in the Okinawa Trough Back-Arc Basin

The Yonaguni Knoll IV hydrothermal vent field (24°51′N, 122°42′E) is located at water depths of 1370–1385 m near the western edge of the southern Okinawa Trough. During the YK03–05 and YK04–05 expeditions using the submersible Shinkai 6500, both hydrothermal precipitates (sulfide/sulfate/carbonate) and high temperature fluids (Tmax = 328°C) presently venting from chimney‐mound structures were extensively sampled. The collected venting fluids had a wide range of chemistry (Cl concentration 376–635 mmol kg^?1), which is considered as evidence for sub‐seafloor phase separation. While the Cl‐enriched smoky black fluids were venting from two adjacent chimney‐mound structures in the hydrothermal center, the clear transparent fluids sometimes containing CO₂ droplet were found in the peripheral area of the field. This distribution pattern could be explained by migration of the vapor‐rich hydrothermal fluid within a porous sediment layer after the sub‐seafloor phase separation. The collected hydrothermal precipitates demonstrated a diverse range of mineralization, which can be classified into five groups: (i) anhydrite‐rich chimneys, immature precipitates including sulfide disseminations in anhydrite; (ii) massive Zn‐Pb‐Cu sulfides, consisting of sphalerite, wurtzite, galena, chalcopyrite, pyrite, and marcasite; (iii) Ba‐As chimneys, composed of barite with sulfide disseminations, sometimes associated with realgar and orpiment overgrowth; (iv) Mn‐rich chimneys, consisting of carbonates (calcite and magnesite) and sulfides (sphalerite, galena, chalcopyrite, alabandite, and minor amount of tennantite and enargite); and (v) pavement, silicified sediment including abundant native sulfur or barite. Sulfide/sulfate mineralization (groups i–iii) was found in the chimney–mound structure associated with vapor‐loss (Cl‐enriched) fluid venting. In contrast, the sulfide/carbonate mineralization (group iv) was specifically found in the chimneys where vapor‐rich (Cl‐depleted) fluid venting is expected, and the pavement (group v) was associated with diffusive venting from the seafloor sediment. This correspondence strongly suggests that the subseafloor phase separation plays an important role in the diverse range of mineralization in the Yonaguni IV field. The observed sulfide mineral assemblage was consistent with the sulfur fugacity calculated from the FeS content in sphalerite/wurtzite and the fluid temperature for each site, which suggests that the shift of the sulfur fugacity due to participation of volatile species during phase separation is an important factor to induce diverse mineralization. In contrast, carbonate mineralization is attributed to the significant mixing of vapor‐rich hydrothermal fluid and seawater. A submarine hydrothermal system within a back‐arc basin in the continental margin may be considered as developed in a geologic setting favorable to a diverse range of mineralization, where relatively shallow water depth induces sub‐seafloor phase separation of hydrothermal fluid, and sediment accumulation could enhance migration of the vapor‐rich hydrothermal fluid.     

The role of tectonic shear strain on the illitization mechanism of mixed-layers illite–smectite. A case study from a fault zone in the Northern Apennines,Italy

The influence of tectonic strain on the diagenetic degree and illitization process of mixed-layers illite–smectite at shallow crustal conditions was studied. For this purpose, the modal composition of clay fraction and illite FWHM parameters of argillites deformed by a regional-scale fault zone were studied in detail by XRD, chemical analyses and by SEM observations. Analyses were performed on deformed samples of the fault rock and compared with the non-deformed rocks off the fault zone. In addition, this paper reports a detailed comparative analysis of deformed (shear surfaces and cleavage domains) and non-deformed domains (lithon cores) of a scaly fabric in the fault rock. A systematic increase in illite concentration, a decrease of Kübler index and FWHM₍₀₀₂₎ values, and an enrichment of K⁺ ions were observed in cleavage domains with respect to the non-deformed sediments off the fault zone and the lithon cores within the fault rock. Migration of K⁺-rich fluids along scaly cleavage domains causes progressive conversion of smectite-rich I–S to illite-rich I–S and thickening of illite crystallites along the c-direction. Changes in mineralogical and crystallographic parameters, therefore, seem to be strongly controlled by shear plane development in highly sheared rocks.     

Contrasted tectonic styles for the Paleoproterozoic evolution of the North China Craton. Evidence for a 2.1 Ga thermal and tectonic event in the Fuping Massif

Structural analysis along with ⁴⁰Ar–³⁹Ar and U–Pb datings in the Fuping massif provide new insight into the evolution of the eastern part of the Trans-North China Belt (North China Craton), from 2.7 Ga to 1.8 Ga. D1 is responsible for the development of a dome-and-basin structure coeval with crustal melting giving rise to migmatite and Nanying gneissic granites at 2.1 Ga. This dome-and-basin architecture resulted from the interference between a N–S compression of a weak ductile crust and gravity-driven vertical flow, in a high thermal regime. The next events involved flat lying ductile thrusting (D2) and normal faulting (D3) dated at around 1880 Ma and 1830 Ma, respectively. The D2 and D3 events belong to the Trans-North China Orogeny that results in the final amalgamation of the North China Craton. The D1 deformation is considered as evidence for an earlier orogen developed around 2.1 Ga prior to the Trans-North China Orogeny. The change in the deformation style between the 2.1 Ga and 1.8 Ga could be viewed as a consequence of the cooling of the continental crust in the North China Craton.