基于人居环境特征的青藏高原“无人区”空间界定

青藏高原独特的高寒环境与自然条件在一定程度上限制了人口的自然分布与有序发展,形成了中国面积大、分布广的“无人区”（UPAs）。然而,当前有关“无人区”面积、分布、特征与区域差异等研究尚无定论。客观、准确界定“无人区”的空间范围,对开展青藏高原资源环境承载力评价、国家公园与生态安全屏障建设等具有重要意义。基于青藏高原居民点分布信息,据其地形、气候、生态、土地利用等要素特征,本文综合表征了居民点的自然—生态—土地利用耦合关系,率定了居民点分布上限的各要素阈值,通过多要素空间叠加构建了“无人区”评价综合模型,并以居民点分布的自然极限、生态（含氧量）下限、土地利用规律为关键阈值界定了青藏高原“无人区”空间范围并分析了其地理分布特征。研究表明：① 以居民点分布累计比例< 0.1%计,确定“无人区”的地形阈值为海拔> 5665 m、相对高差> 2402 m、地形起伏度> 8.59,气候阈值为相对湿度< 76.2%、温湿指数< 33或 > 71。② 根据居民点分布及人体对含氧量耐受情况,确定“无人区”的生态阈值为气压< 500 hpa、大气含氧量< 40%。③ 青藏高原严格“无人区”面积达1912 km²,其中新疆699 km²、四川413 km²、西藏331 km²、青海291 km²、甘肃178 km²。空间上呈零星分散状,多分布在四川贡嘎山、珠穆朗玛峰附近等极高山地区、可可西里东部—罗布泊地区;以及少部分分布在青海柴达木盆地。     

海上低渗透油田特点及开发策略探讨

目前海油低渗探明储量和低渗的产量分别占海油总探明储量和总产量比例虽然小,但在海油实现5 000万t年产后稳产阶段所起的作用将会越来越大。对于海上10～50 mD之间的一般低渗为主要考虑的勘探开发对象,当渗透率是5～10 mD之间的特低渗油田时需要优选出构造相对简单、储层比较连续的区块开发;对于复杂断块特低渗透油田和小于5 mD的超低渗油田,在目前海上经济技术条件下暂不具备勘探开发条件。在海上低渗透油田开发中需考虑压裂、注水的综合应用,尽量采用水平井和分支井开发,并且在开采过程中注意低渗储层的保护。     

中国大陆下扬子及邻区地壳结构基本特征:深地震测深研究综述

系统回顾了20世纪70年代以来在中国大陆下扬子及其邻区开展的深地震测深工程,总结了相关宽角反射/折射地震资料的波组特征及地壳结构的基本特征。下扬子及邻区深地震测深资料普遍具有较清晰的初至震波Pg、上地壳底界面反射波P1、中地壳底界面反射波P3、莫霍界面反射波Pm及上地幔顶部首波Pn,震相连续,易追踪对比。受浅表沉积盖层或基岩等的影响,Pg波常出现局部延迟滞后或走时超前现象。尤其是大别造山带个别炮点的反射能量较弱或同相轴扭曲、波形紊乱等,均与地壳内界面和莫霍面的深度突变或破碎有关。该区域地壳结构大致分为上、中、下3层,但视资料情况中地壳和下地壳又可进一步划分为2个亚层。华北地台和扬子地台地壳厚度30~36km,莫霍界面形态变化较缓,存在局部隆起,下地壳平均速度6.7±0.3km/s。但大别造山带下方地壳厚度32~41km,莫霍界面下凹且出现4~7km垂向错断,下地壳平均速度6.8±0.2km/s。     

浅谈中国大陆东缘中生代地质演化与泛太平洋板块活动的关系

本文旨在厘清中生代中国东缘受泛太平洋板块俯冲作用影响下,其可能形成的地质记录的时空分布与泛太平洋板块活动的关系。前者主要从岩浆、构造、沉积盆地的时空演化等角度出发,后者的运动学参数集中在俯冲角度、速度、方向等维度。结果显示：俯冲角度、速度以及方向的改变都有可能形成与之对应的地质事件;但是中国东缘（东北、华北和华南）区域地质记录间的差异也表明,即使都可能遭受俯冲作用,由于个体特殊的构造背景,最终的结果也不尽相同。我们对于中国东缘中、新生代的这一特殊构造现象进行了讨论,得出如下结论：首先三联点力学稳定性分析结果认为,在华北和华南碰撞拼合后,中国大陆东缘可能存在TTT、TTR或者TFT的三联点,而不是简单的稳定的被动大陆边缘;另外,中国华南早、中侏罗世近东西向岩浆岩的形成可能与法拉隆板块和伊泽奈岐板块洋中脊俯冲有关;晚侏罗-早白垩世的板片后撤由NWW向的伊泽奈岐板块与太平洋板块的洋中脊扩张作用所致;而华北克拉通东部记录侏罗纪伊泽奈岐板块俯冲的证据不足,可能并没有发生板块俯冲作用,表现为板块运动与作为中国东部最为薄弱地区的郯庐断裂带的强烈耦合作用。     

丰、枯水期长江口邻近海域浮游植物群落结构特征及其环境影响初探

通过2013年3月和8月在长江口及其邻近海域进行的多学科综合调查,研究了枯水期和丰水期浮游植物的群落结构和空间分布特征,并探讨了影响其分布的环境因子效应。枯水期共发现浮游植物3门41属80种（不包括变种和变型）,以硅藻为主,主要优势种为具槽帕拉藻（Paralia sulcata）;浮游植物细胞丰度介于0.15×103~16.35×103 cells/L,平均值为（3.24±3.14）×103 cells/L;浮游植物细胞丰度在长江口外东北部海域形成高值,垂直变化较小,硅藻刻画了浮游植物的空间分布。丰水期共发现浮游植物4门67属135种（不包括变种和变型）,甲藻物种数量和细胞丰度均升高,主要优势种为东海原甲藻（Prorocentrum donghaiense）和骨条藻（Skeletonema sp.）;浮游植物细胞丰度介于0.2×103~1 925.45×103 cells/L,平均值为（41.67±186.00）×103 cells/L;浮游植物细胞丰度在长江口外形成南北两个高值区,随水深增加,细胞丰度逐渐降低。浮游植物的空间分布受长江口冲淡水影响,与盐度和浊度有显著的相关性;N/P比影响浮游植物群落结构,随着N/P比升高,甲藻的相对丰度升高,硅藻的相对丰度逐渐降低。浮游植物在层化水体的上层大量繁殖是底层低氧形成的必要条件,硅藻具有较高的沉降速率,因而以硅藻为主的群落更利于低氧的形成。     

网络RTK在大比例尺测图控制中的应用

简要介绍了网络RTK的基本原理和用其进行测图控制测量的作业方法,并用实例对网络RTK进行测图控制的内符合精度与外符合精度进行了验证,结果表明,采用网络RTK进行测图控制的可靠性与精度均能得到保证,且不受误差累积的影响。     

中国内陆河流域植被对气候变化的敏感性差异(英文)

Terrestrial ecosystem and climate system are closely related to each other. Faced with the unavoidable global climate change, it is important to investigate terrestrial ecosystem responding to climate change. In inland river basin of arid and semi-arid regions in China, sensitivity difference of vegetation responding to climate change from 1998 to 2007 was analyzed in this paper. (1) Differences in the global spatio-temporal distribution of vegetation and climate are obvious. The vegetation change shows a slight degradation in this whole region. Degradation is more obvious in densely vegetated areas. Temperature shows a gen-eral downward trend with a linear trend coefficient of -1.1467. Conversely, precipitation shows an increasing trend with a linear trend coefficient of 0.3896. (2) About the central tendency response, there are similar features in spatial distribution of both NDVI responding to precipitation (NDVI-P) and NDVI responding to AI (NDVI-AI), which are contrary to that of NDVI responding to air temperature (NDVI-T). Typical sensitivity region of NDVI-P and NDVI-AI mainly covers the northern temperate arid steppe and the northern temperate desert steppe. NDVI-T typical sensitivity region mainly covers the northern temperate desert steppe. (3) Regarding the fluctuation amplitude response, NDVI-T is dominated by the lower sensi-tivity, typical regions of the warm temperate shrubby, selui-shrubby, bare extreme dry desert, and northern temperate meadow steppe in the east and temperate semi-shrubby, dwarf ar-boreous desert in the north are high response. (4) Fluctuation amplitude responses between NDVI-P and NDVI-AI present a similar spatial distribution. The typical sensitivity region mainly covers the northern temperate desert steppe. There are various linear change trend re-sponses of NDVI-T, NDVI-P and NDVI-AI. As to the NDVI-T and NDVI-AI, which are influ-enced by the boundary effect of semi-arid and semi-humid climate zones, there is less cor-relation of their linear change tendency along the border. There is stronger correlation in other regions, especially in the NDVI-T in the northern temperate desert steppe and NDVI-AI in the warm temperate shrubby, selui-shrubby, bare, extreme and dry desert.     

A simple kriging method incorporating multiscale measurements in geochemical survey

In this study, we propose a kriging algorithm, multiscale kriging model, to incorporate geochemical data observed at multiscales (multiresolutions). We assume that there are a number of measurements at different scales, and that the target scale at which the parameter values are needed may be different from the measurement scales. Several synthetic examples and the vanadium geochemical data from 8402 stream sediment samples in Zhejiang Province, China, have been used to illustrate the method. These examples demonstrate that, by incorporating measurements from all scales, the estimated field is better than the field estimated using measurements from any individual scale. This method also allows us to estimate a parameter field at the scale that does not have any measurements.     

K-bentonite,black-shale and flysch successions at the Ordovician–Silurian transition,South China: Possible sedimentary responses to the accretion of Cathaysia to the Yangtze Block and its implications for the evolution of Gondwana

The K-bentonite, black shale and flysch successions at the Ordovician–Silurian transition in South China have been the subject of comprehensive investigations relative to the probable accretion of the Yangtze Block and the questionable Cathaysia Block. First, the geochemical analyses of K-bentonites show that the parent magma originated in syn-collisional, volcanic-arc and within-plate tectonic settings, which produced mainly intermediate-to-felsic series magmas, associated with continuous collision and subduction of paleo-continental blocks/arcs. Further, the regional distribution of K-bentonite thickness indicates that voluminous explosive volcanism was located in the present southeastern shoreline provinces of China. Secondly, northwestwardly migrating, Ordovician–Silurian, transitional flysch successions, and the accompanying diachronous K-bentonite-bearing black-shale interval, as well as the related, overlying, shallowing-upward succession at the interior of the Yangtze Block, developed as an unconformity-bound sequence that mirrors foreland-basin tectophase cycles in the Appalachian basin. The above features suggest that the sequence accumulated in a similar foreland basin, which formed in response to adjacent deformational loading in a northwesterly migrating orogen located to the southeast. Geochemical and paleocurrent data from the turbiditic flyschoid sandstones also support these depositional settings. Accordingly, it seems that all criteria strongly support the presence of an Ordovician–Silurian, subduction-related orogen resulting from collision with a block to the southeast that must have been the original “Cathaysia Block” of Grabau and later workers. The K-bentonite, black-shale and flysch successions can be regarded as distal, foreland responses to the continuous northwestward collision and accretion of the Cathaysia Block to the Yangtze Block. Hence, we prefer to suggest that the suture zone with the sensu stricto Cathaysia Block probably developed along previously identified late Early Paleozoic suture relicts in the shoreline provinces of southeast China. On the other hand, although accretion of fragments with Cathaysian affinities to the Yangtze Block may have begun as early as Middle to Late Proterozoic time, the Ordovician–Silurian orogeny described above probably reflects the final phase of accretion between the two blocks. Moreover, when combined with similar peri-Iapetan orogenic events in other areas during the same period, this accretion event may have been part of a major stage of global tectonic reconstruction in the evolution of Gondwana.     

西藏多龙矿集区萨玛隆闪长岩LA-ICP-MS锆石U-Pb年龄和岩石化学特征及其对成矿背景的约束

西藏多龙矿集区是目前班公湖-怒江成矿带内最具潜力的找矿远景区,矿集区内已发现4处大型斑岩铜矿,但其成矿背景尚有争议。通过开展成矿前的萨玛隆闪长岩锆石U-Pb测年、岩石化学分析,结合区域内构造发育序次,对系列斑岩铜矿的成矿背景进行探讨。对萨玛隆闪长岩中进行LA-ICP-MS锆石U-Pb测年,获得23颗锆石的~(206)Pb/~(238)U年龄加权平均值为121.6±1.7Ma(MSWD=1.9),代表了闪长岩的成岩年龄。萨玛隆闪长岩的全岩岩石化学分析结果显示,该岩石属于中钾富钠岩石,富集轻稀土元素和大离子亲石元素,亏损重稀土元素和高场强元素,具有高Sr、低Y特征,相对富集Cr、Ni等不相容元素,有埃达克岩的亲和性。闪长岩具相对较高的(~(87)Sr/~(86)Sr)i值和较低的(~(143)Nd/~(144)Nd)i值、ε_(Nd)(t)。全岩岩石化学特征显示,萨玛隆闪长岩起源于下地壳角闪岩相,可能有幔源物质混入。矿区内早期走滑断层切穿萨玛隆闪长岩,指示多龙矿集区内主要控岩-控矿走滑断层可能形成于116~121Ma,多龙矿集区内系列斑岩铜矿形成于班公湖-怒江洋向北俯冲末期的构造转换阶段。