福建省永泰县东门旗山滑坡诱发机理与防治措施

为明确降雨诱发滑坡机理及为防治措施确定依据,本文以福建省永泰县东门旗山滑坡为研究案例,在充分的地质勘探资料以及降雨期间滑坡位移监测数据的基础上,从内部与外部因素两个方面分析了滑坡的诱发机理,并通过数值方法对滑坡稳定性演化历程进行了反分析,将滑坡治理分为应急处理与长期加固两个阶段。在应急处理阶段,以拦排地表与地下水为主要工程措施,依据滑坡体不同部位滑动速率与降雨量的关系,验证推移式滑坡判断,得出先将排水措施布设于滑坡下部的结论;在长期加固方面,以抗滑桩为主要加固措施,以抗滑桩工程造价最低为优化目标,结合数值模拟与理论计算方法,得到最优抗滑桩设计方案为布桩于滑坡体中下部、桩径1.0 m、桩净距与中心距分别为2.0 m和3.0 m。     

库车南斜坡中—新生界油气运移地球化学示踪

库车南部斜坡中—新生界属于库车陆相油气系统,油气主要来源于库车坳陷的三叠系和侏罗系烃源岩。本文利用色谱、色谱-质谱及碳同位素分析手段,对库车南部斜坡带已发现的白垩系和古近系油气地球化学组成特征进行了详细研究,在明确油气来源基础上,根据典型油气藏解剖,分析油气运移输导路径,优选油气地球化学运移参数示踪油气运移充注路径。研究表明:库车南斜坡中—新生界原油呈现低密度、低黏度、低凝固点、低含硫及高含蜡的陆相原油特征。原油总体以藻类和水生浮游生物母源为主,反映生烃母质弱还原-弱氧化的沉积环境,体现混合型干酪根母源特征,其中白垩系原油母源以湖相水生生物为主,主要来自三叠系湖相烃源岩;古近系原油除了三叠系湖相烃源岩的贡献外,伴随有以陆生高等植物输入为主的侏罗系煤系烃源岩。天然气具有中等甲烷含量、重烃含量高、氮气含量高和无硫化氢的特点,白垩系天然气主要是三叠系湖相原油伴生油型气;古近系天然气主体属于煤成气,主要来源于中下侏罗统煤系烃源岩,部分混有早期三叠系湖相烃源岩的原油伴生油型气。区内中—新生界发育由砂体、不整合、断裂构成的复杂油气输导体系,三叠系烃源岩生成的大量原油主要是沿白垩系底部不整合或下伏连...     

西沙群岛东岛轮藻的发现及其意义

东岛是西沙群岛第二大岛,东岛"牛塘"是西沙群岛中少见的淡水型湖泊,在牛塘的表层沉积物中发现了大量现生轮藻藏卵器,经鉴定为Lamprothamnium（丽枝轮藻属）。其藏卵器为长球形或亚长球形,最大长度（LPA）为560~780 μm,最大宽度（LED）为360~500 μm,等轴率（ISI）为156~194。前人对东岛牛塘沉积物钻孔的研究中均没有轮藻的相关报道,此次发现的轮藻是南海诸岛轮藻的首次发现,轮藻的发现意味着该地的淡水生态系统发育到更加稳定的新阶段,对西沙群岛淡水生态系统的研究有重要意义,也为南海珊瑚岛礁淡水生态系统的管理与保护提供科学依据。     

岩石润湿性的核磁共振表征方法与初步实验结果

随着石油勘探开发领域的不断扩大,某些复杂油气藏尤其是致密油气的岩石物理响应,受岩石润湿性变化的影响越来越明显,影响油气藏的评价以及后续勘探开发,识别和评价岩石润湿性成为重要的研究课题.核磁共振弛豫可以有效表征多孔介质孔隙及其流体分布,特别是通过T₁-T₂弛豫图谱能够获得流体分子与孔隙表面相互作用的信息,进而为孔隙表面润湿性质的判断提供了可能性.本文首先讨论了T₁-T₂弛豫谱表征孔隙介质润湿强度的理论基础,然后,采用一阶近似方法对孔隙表面流体分子的核磁共振弛豫分布进行正演模拟,建立T₁/T₂比值法判别孔隙介质润湿性的基本方法.最后,选取玻璃珠和天然砂岩样品进行初步实验,验证方法的合理性.结果表明,当岩石饱和双相流体时,润湿相流体T₁/T₂值高于非润湿相流体,通过观察不同饱和度状态T₁-T₂二维图谱的变化,能够判断岩石的润湿性.本文的理论分析与初步实验结果为岩石润湿性研究提供了新的手段,对核磁共振测井探测储层润湿性也具有一定的应用价值.

     

Insight-HXMT observations of the Crab pulsar

We report on X-ray emission properties of the Crab pulsar(PSR B0531+21) using observations by Insight-HXMT during its first year after launch. We obtained high signal-to-noise profiles in the X-ray energy band 11–250 keV. We have confirmed an increase in the flux ratio of the second peak over the main peak with increasing energy, consistent with other missions. The separation of the two peaks shows no significant trend with increasing energy. The phase-averaged spectrum, fitted by a logpar model, and the phase-resolved spectra of the Crab pulsar, fitted by a powerlaw in the different energy bands of HXMT, are consistent with RXTE and NuSTAR in that photon indices evolve as a function of phase as well as a function of energy, contributing to a broadband modeling.     

Subduction history of the Paleo-Pacific slab beneath Eurasian continent: Mesozoic-Paleogene magmatic records in Northeast Asia

This paper presents a review on the rock associations, geochemistry, and spatial distribution of Mesozoic-Paleogene igneous rocks in Northeast Asia. The record of magmatism is used to evaluate the spatial-temporal extent and influence of multiple tectonic regimes during the Mesozoic, as well as the onset and history of Paleo-Pacific slab subduction beneath Eurasian continent. Mesozoic-Paleogene magmatism at the continental margin of Northeast Asia can be subdivided into nine stages that took place in the Early-Middle Triassic, Late Triassic, Early Jurassic, Middle Jurassic, Late Jurassic, early Early Cretaceous, late Early Cretaceous, Late Cretaceous, and Paleogene, respectively. The Triassic magmatism is mainly composed of adakitic rocks, bimodal rocks, alkaline igneous rocks, and A-type granites and rhyolites that formed in syn-collisional to post-collisional extensional settings related to the final closure of the Paleo-Asian Ocean. However, Triassic calc-alkaline igneous rocks in the Erguna-Xing’an massifs were associated with the southward subduction of the Mongol-Okhotsk oceanic slab. A passive continental margin setting existed in Northeast Asia during the Triassic. Early Jurassic calc-alkaline igneous rocks have a geochemical affinity to arc-like magmatism, whereas coeval intracontinental magmatism is composed of bimodal igneous rocks and A-type granites. Spatial variations in the potassium contents of Early Jurassic igneous rocks from the continental margin to intracontinental region, together with the presence of an Early Jurassic accretionary complex, reveal that the onset of the Paleo- Pacific slab subduction beneath Eurasian continent occurred in the Early Jurassic. Middle Jurassic to early Early Cretaceous magmatism did not take place at the continental margin of Northeast Asia. This observation, combined with the occurrence of low-altitude biological assemblages and the age population of detrital zircons in an Early Cretaceous accretionary complex, indicates that a strike-slip tectonic regime existed between the continental margin and Paleo-Pacific slab during the Middle Jurassic to early Early Cretaceous. The widespread occurrence of late Early Cretaceous calc-alkaline igneous rocks, I-type granites, and adakitic rocks suggests low-angle subduction of the Paleo-Pacific slab beneath Eurasian continent at this time. The eastward narrowing of the distribution of igneous rocks from the Late Cretaceous to Paleogene, and the change from an intracontinental to continental margin setting, suggest the eastward movement of Eurasian continent and rollback of the Paleo- Pacific slab at this time.     

Evolution of the East China Sea sedimentary environment in the past 14 kyr: Insights from tetraethers-based proxies

We reconstruct the environmental evolution of the East China Sea in the past 14 kyr based on glycerol dialkyl glycerol tetraethers(GDGTs) in a sediment core from the subaqueous Yangtze River Delta. Two primary phases are recognized. Phase I(13.8–8 cal kyr BP) reflects a predominantly continental influence, showing distinctly higher concentrations of branched GDGTs(averaged 143 ng/g dry sediment weight, dsw) than isoprenoid GDGTs(averaged 36 ng/g dsw), high BIT index(branched vs. isoprenoid tetraethers) values(0.78) and a fluctuating GDGT-0/crenarchaeol ratio(R_(0/5), varied from 0.52 to 3.81). Within this interval, temporal increases of terrestrial and marine influence are attributed to Younger Dryas(YD)(ca. 12.9–12.2 cal kyr BP) cold event and melt-water pulse(MWP)-1B(11.5–11.1 cal kyr BP), respectively. The prominent transition from 8 to 7.9 cal kyr BP shows a sharp decrease in BIT index value(0.4) and increase in crenarchaeol, which marks the beginning of phase II. Afterwards, the proxies remain relatively constant, which indicates that phase II(7.9 cal kyr BP-present) is a shelf sedimentary environment with high stand of sea level. Overall, the BIT index in our record serves as a good marker for terrestrial influence at the site, and likely reflects the flooding history of the region. The TEX_(86)(Tetra Ether Index of tetraethers consisting of 86 carbons) proxy is not applicable in phase I because of an excess terrestrial influence; but it seems to be valid for revealing the annual SST in phase II(21.6±0.9°C, n=49). In contrast, the MBT'/CBT(Methylation of Branched Tetraethers and Cyclization of Branched Tetraethers) proxy appears to faithfully record the annual mean air temperature(MAT)(14.3±0.63°C, n=68) and presents an integrated signal over the middle and lower Yangtze River drainage basin.     

黑藻（Hydrilla verticillata）生长和锚定的沉积物条件需求初步研究

恢复沉水植被是湖泊生态修复工程中的关键环节,明确沉水植物生长和锚定的环境条件是恢复沉水植被的重要前提。本研究以湖泊生态修复常用的沉水植物黑藻（Hydrilla verticillata）为例,结合文献分析、控制实验和野外调查3种方法研究了其生长和锚定的沉积物条件需求。结果表明,黑藻在沉积物有机质含量为0.16%～38.36%、密度为1.08～2.06g/cm3、含水率为19.80%～78.14%的范围内能正常生长,在沉积物有机质含量为0.64%～21.84%、密度为1.09～2.06 g/cm3、含水率为25.32%～72.06%的范围内适宜生长;在沉积物有机质含量为0.29%～18.30%、密度为1.16～2.06 g/cm3、含水率为19.80%～72.17%的范围内,黑藻植株能够稳定定植。本研究结果可为恢复黑藻提供初步的边界条件数据,也可为其它生态修复常用沉水植物的类似研究提供方法上的借鉴。     

太湖表面温度与表层水温差异及其影响因素的观测分析

湖泊“皮肤效应”指表面温度与表层水温的差异,量化“皮肤效应”并分析其影响因素有助于理解湖泊物理、化学、生物和生态过程对气候变暖的响应。本文基于太湖中尺度通量网2011—2020年水温梯度、辐射四分量和小气候观测数据,定量分析了在不同时间尺度和不同天气条件下“皮肤效应”的差异及其影响因素。结果表明,太湖暖“皮肤效应”在15:00—16:00最强,可达1.95℃;冷“皮肤效应”在7:00—8:00最强,达-0.50℃。“皮肤效应”强度春季最强,夏季最弱。因此,无法用表层水温观测值直接验证卫星午后过境反演得到的太湖湖面温度,其偏差可达2℃,尤其在春季。年际尺度上,太湖表面温度上升速率为0.14℃/a,与同期气温上升速率相当,表层水温上升速率为0.12℃/a。使用遥感反演的表面温度表征的太湖升温速率会比传统的表层水温观测结果快0.02℃/a。晴天小风时暖“皮肤效应”最强,为1.64℃;阴天大风时“皮肤效应”最弱,仅为0.32℃。相较于太阳辐射,风速对太湖水温“皮肤效应”的影响更大,风的扰动是影响太湖水温“皮肤效应”的首要因素。此外,基于10年观测数据建立了适用于太湖水温“皮肤效应”的风速参数化...     

西藏地区联合应用X荧光法和快金分析法快速追踪和评价金异常源

论述了在西藏地区某金矿区金异常的追踪和评价工作中，联合应用Ｘ荧光法和快金分析法的效果，以Ｘ荧光法现场测定与金矿化密切相关亲铜元素（或亲铜元素组合），发现，追踪含金矿（化）脉（带），以快金分析法及时对矿（化）脉定性，实践表明，这是一种简捷，快速，经济和有效的工作方法。