椒江口潮间带大型底栖动物群落beta多样性分析

于2007年10月在椒江口共布设6条潮间带采样断面,每条断面在中潮带上区、中区、下区和低潮区各设1站位进行大型底栖动物采样。分析了不同采样站位数与大型底栖动物种数的关系,选用Wilson-Shmidabeta多样性测度方法,对以下3种空间环境梯度下大型底栖动物群落beta多样性进行了研究:(1)断面内垂直环境梯度;(2)河流到海洋的环境梯度;(3)河口两岸间的距离梯度。分析了不同采样站位数对群落beta多样性指数的影响,结果显示:(1)随着采样站位数的增加,物种数呈增加趋势但增速渐慢,同时beta多样性指数呈下降趋势;(2)不同的潮区间隔下的be-ta多样性指数均有显著差异;(3)在北岸和南岸,随着断面间距的增加beta多样性指数均呈升高趋势,而且与各断面的沉积物粒度、油类含量呈显著相关;(4)椒江口为喇叭形河口,随着河口两岸断面距离的增加beta多样性指数呈升高趋势。     

中国近海海洋要素最大跃层强度及其对应深度的分布规律研究

利用海洋模态重构方法对LEVITUS数据库数据进行了分析,获得了中国近海的温度、密度和声速的最大跃层强度及其深度的月平均变化规律.海洋要素的最大跃层强度在7、8月份达到最大,而且分布均匀,最大跃层强度对应的深度为全年最浅.12月至次年3月的最大跃层强度最小,分布杂乱,最大跃层强度对应的深度为全年最深.其他月份的分布介于二者之间.     

一种污水排海的近远区计算与控制方法──以大亚湾水容量计算及污水排海为例

针对点容量计算中混合区限制的要求，采用了动量积分法、经验公式法和有限差分法，分别对污水排放后可能引起的近区、过渡区和远区的污水浓度变化进行了模拟预测，并就一定的限制性条件对容量点近区、高浓度混合区及容量点远区影响范围进行了分析。在大亚湾水容量计算及污水排海规划中的应用表明，该法具有计算机时较省、精度相对较高等优点。     

六盘山植物区系基本特征的初步分析

六盘山位于陕甘宁交接地区,属于半湿润气候向半干旱气候的过渡带,是黄土高原生物多样性最丰富的地区之一,有维管植物836种,隶属于93科,359属。本区属于泛北极植物区、中国-日本森林植物亚区、华北植物地区的黄土高原亚地区。全部种子植物可分为13个分布区类型和12个变型,以北温带分布类型为主,与其他植物区系联系广泛,但特有属较贫乏。六盘山与小陇山、太白山和中条山的属相似性系数较高,均达60%以上,表明几座山体处于相似的生物气候背景之下,地理隔离性不明显。与贺兰山的属相似性系数低于60%,因为贺兰山位于干旱的荒漠与半荒漠区,可能有地理隔离作用。     

基于Mann-Kendall方法的胶东半岛海岸带归一化植被指数趋势分析

利用1998—2008年SPOT/VEGETATION逐旬共372期归一化植被指数时间序列影像数据,引入Mann-Kendall非参数趋势检验方法,分析了胶东半岛最近10 a来的归一化植被指数变化趋势。结果表明,最近10 a来,胶东半岛归一化植被指数变化趋势以衰减区域居主导地位,其中有明显衰减变化趋势的区域占半岛总面积的19.3%,有明显增强变化趋势的区域仅占半岛总面积的2.8%。归一化植被指数衰减区域在空间上沿海岸线呈环状分布,从沿海岸到远离海岸,归一化植被指数增强趋势逐渐明显,衰减最明显的区域大部分位于半岛沿海30 km以内,植被增强趋势最明显区域位于半岛中部山地及沿海防护林地区。人类活动及其空间分布是归一化植被指数变化的主要因素,其中沿海城市化、工业化和海岸湿地开发利用程度的提高导致归一化植被指数衰减,而山地植被保护和海岸防护林建设导致归一化植被指数增强。     

Calibration and use of continuous heat-type automated seepage meters for submarine groundwater discharge measurements

Submarine groundwater discharge (SGD) assessments were conducted both in the laboratory and at a field site in the northeastern Gulf of Mexico, using a continuous heat-type automated seepage meter (seepmeter). The functioning of the seepmeter is based on measurements of a temperature gradient in the water between downstream and upstream positions in its flow pipe. The device has the potential of providing long-term, high-resolution measurements of SGD. Using a simple inexpensive laboratory set-up, we have shown that connecting an extension cable to the seepmeter has a negligible effect on its measuring capability. Similarly, the observed influence of very low temperature (≤3 °C) on seepmeter measurements can be accounted for by conducting calibrations at such temperatures prior to field deployments. Compared to manual volumetric measurements, calibration experiments showed that at higher water flow rates (>28 cm day⁻¹ or cm³ cm⁻² day⁻¹) an analog flowmeter overestimated flow rates by ≥7%. This was apparently due to flow resistance, turbulence and formation of air bubbles in the seepmeter water flow tubes. Salinity had no significant effect on the performance of the seepmeter. Calibration results from fresh water and sea water showed close agreement at a 95% confidence level significance between the data sets from the two media (R² = 0.98). Comparatively, the seepmeter SGD measurements provided data that are comparable to manually-operated seepage meters, the radon geochemical tracer approach, and an electromagnetic (EM) seepage meter.     

A new understanding of Demala Group complex in Chayu Area,southeastern Qinghai-Tibet Plateau: Evidence from zircon U-Pb and mica 40Ar/39Ar dating

The Chayu area is located at the southeastern margin of the Qinghai-Tibet Plateau. This region was considered to be in the southeastward extension of the Lhasa Block, bounded by Nujiang suture zone in the north and Yarlung Zangbo suture zone in the south. The Demala Group complex, a set of high-grade metamorphic gneisses widely distributed in the Chayu area, is known as the Precambrian metamorphic basement of the Lhasa Block in the area. According to field-based investigations and microstructure analysis, the Demala Group complex is considered to mainly consist of banded biotite plagiogneisses, biotite quartzofeldspathic gneiss, granitic gneiss, amphibolite, mica schist, and quartz schist, with many leucogranite veins. The zircon U-Pb ages of two granitic gneiss samples are 205 ± 1 Ma and 218 ± 1 Ma, respectively, representing the ages of their protoliths. The zircons from two biotite plagiogneisses samples show core-rim structures. The U-Pb ages of the cores are mainly 644 –446 Ma, 1213 –865 Ma, and 1780 –1400 Ma, reflecting the age characteristics of clastic zircons during sedimentation of the original rocks. The U-Pb ages of the rims are from 203 ± 2 Ma to 190 ± 1 Ma, which represent the age of metamorphism. The zircon U-Pb ages of one sample taken from the leucogranite veins that cut through granitic gneiss foliation range from 24 Ma to 22 Ma, interpreted as the age of the anatexis in the Demala Group complex. Biotite and muscovite separates were selected from the granitic gneiss, banded gneiss, and leucogranite veins for ⁴⁰Ar/³⁹Ar dating. The plateau ages of three muscovite samples are 16.56 ± 0.21 Ma, 16.90 ± 0.21 Ma, and 23.40 ± 0.31 Ma, and the plateau ages of four biotite samples are 16.70 ± 0.24 Ma, 16.14 ± 0.19 Ma, 15.88 ± 0.20 Ma, and 14.39 ± 0.20 Ma. The mica Ar-Ar ages can reveal the exhumation and cooling history of the Demala Group complex. Combined with the previous research results of the Demala Group complex, the authors refer that the Demala Group complex should be a set of metamorphic complex. The complex includes not only Precambrian basement metamorphic rock series, but also Paleozoic sedimentary rock and Mesozoic granitic rock. Based on the deformation characteristics, the authors concluded that two stages of the metamorphism and deformation can be revealed in the Demala Group complex since the Mesozoic, namely Late Triassic-Early Jurassic (203 –190 Ma) and Oligocene –Miocene (24 –14 Ma). The early stage of metamorphism (ranging from 203 –190 Ma) was related to the Late Triassic tectono-magmatism in the area. The anatexis and uplifting-exhumation of the later stage (24 –14 Ma) were related to the shearing of the Jiali strike-slip fault zone. The Miocene structures are response to the large-scale southeastward escape of crustal materials and block rotation in Southeast Tibet after India-Eurasia collision.©2021 China Geology Editorial Office.     

大别山北麓梅山群中韧性剪切带变形特征及形成机制

梅山群为分布于北淮阳地区位于佛子岭群之下、逆掩于晚泥盆世—石炭纪杨山煤系和中侏罗统红层之上的一套中—浅变质岩系，在其中、上部发育ＮＷ走向的韧性剪切带，产状与区域片理一致。对韧性剪切带及其变形岩石———糜棱岩的宏微观构造研究表明，韧性剪切变形发生于区域变质岩形成之后，具有右旋剪切的运动特点，反映大别山地块向北仰冲过程中所派生的侧向滑移作用     

胶南地区的伸展作用——以胶南—诸城一带为例

胶南地区的胶南—诸城一带存在两期不同方向的伸展构造。早期以形成近ＥＮ向的拉伸线理为特征，并在不同构造层次上显示出不同的变形。出露于研究区中部桃林尚庄隆起的含榴辉岩片麻岩中，主要以ＬＳ的组构为特征，显示出早期伸展作用下地壳岩石的垂直轴缩短、ＥＷ向拉伸的共轴应变；而在把下地壳含榴辉岩片麻岩与以变沉积岩为主的中上地壳岩石分开的韧性滑脱带上，此期伸展作用则表现为从东向西剪切的非共轴简单剪切变形，具有近水平的拉伸线理及近水平的ＥＷ向剪切褶皱和鞘褶皱枢纽。晚期伸展作用表现为近ＳＮ的伸展垮塌作用，形成向北和向南倾斜的两条韧性正剪切带，且遭受低角闪岩高绿片岩相条件下的透入性均匀简单剪切变形，剪切方向分别向北和向南。     

地面预注断层破碎带井筒工艺研究

地面预注断层破碎带研究采用控制性高压劈裂、小段高、水玻璃预处理、钻孔分叉综合技术和工艺，成效显著。