新疆库车县盐水沟北铜矿床地质特征及成因探讨          下载免费PDF全文

刘传朋 《山东国土资源》2018,34(4)

盐水沟北铜矿区位于新疆库车县北部,其大地构造位置处于塔吉克-塔里木陆块区、塔里木陆块、塔里木北缘隆起、库车前陆盆地,区内构造活动强烈。铜矿床赋存于新近纪中新统康村组第一岩性段,矿体呈层状,严格受地层控制。区内共圈定10个铜矿体,矿石矿物主要为孔雀石、赤铜矿、水胆矾、自然铜等,矿体内无夹石,顶、底板围岩均为褐红色及浅红色粉质泥岩。该矿床为砂岩型铜矿床。  相似文献   

青海可可西里地区综合科学考察初报     

李炳元 《山地学报》1990,(3)

本区至今还是综合科学考察的空白区。为查明基本情况,1989年夏以乘汽车路线考察方式穿行该区而作了预查,搜集了当地地质、地理、生物等基本资料。经考察发现,区内野生动物资源丰富,上新世以来火山活动普遍,湖泊众多,矿产资源可能有良好前景;所在区又为自然地域和地质构造的重要界线,对青藏高原研究具有重大科学价值。  相似文献   

陕西秦巴山区农业自然资源开发利用     

刘胤汉  陆立新 《山地学报》1990,(1)

农业自然资源据其在农业利用过程中的地位可分为两类:一类是生成农业自然资源的环境,另一类为可资直接利用的自然生成物(即狭义的农业自然资源)。陕西秦巴山区自然环境的主要特点是:复合山体高峻庞大,地跨暖温带和北亚热带,垂直分异明显。区内有:森林、草场、野生生物、林特产与农作物等多种农业自然资源。据此,提出了本区农业自然资源的开发利用途径。  相似文献   

Possible Density Change of the Origin of North Pacific Intermediate Water Due to Double Diffusion in the Mixed Water Region     

Ryuichiro?InoueEmail author  Jiro?Yoshida 《Journal of Oceanography》2005,61(5):871-883

In this study we test Talley's hypothesis that Oyashio winter mixed-layer water (26.5–26.6σ _θ) increases its density to produce the North Pacific Intermediate Water (NPIW) salinity minimum (26.7– 26.8σ_θ) in the Mixed Water Region, assuming a combination of cabbeling and double diffusion. The possible density change of Oyashio winter mixed-layer water is discussed using an instantaneous ratio of the change of temperature and salinity along any particular intrusion (R _l ). We estimate the range of R _l ^DD required to convert Oyashio winter mixed-layer water to the NPIW salinity minimum due to double diffusion, and then assume double-diffusive intrusions as this conversion mechanism. A double-diffusive intrusion model is used to estimate R _l ^DD in a situation where salt fingering dominates vertical mixing, as well as to determine whether Oyashio winter mixed-layer water can become the NPIW salinity minimum. Possible density changes are estimated from the model R _l ^DD by assuming the amount of density change due to cabbeling. From these results, we conclude that Oyashio winter mixed-layer water contributes to a freshening of the lighter layer of the NPIW salinity minimum (around 26.70σ_θ) in the MWR.  相似文献   

The distribution of chlorophyll-a and dominant planktonic components in the coastal transition zone off Concepción, central Chile, during different oceanographic conditions     

Carmen E. Morales  Humberto E. González  Gabriel Yuras  Leonardo R. Castro 《Progress in Oceanography》2007,75(3):452-469

The oceanographic setting and the planktonic distribution in the coastal transition zone off Concepción (∼35-38°S, ∼73-77°W), an area characterized by its high biological production, were assessed during two different seasons: austral spring with equatorward upwelling favorable winds and austral winter with predominately northerly winds. Oceanographic and biological data (total chlorophyll-a, particulate organic carbon, microplankton, large mesozooplankton >500 μm as potential consumers of microplankton) were obtained during two cruises (October 1998, July 1999) together with satellite imagery for wind stress, geostrophic flow, surface temperature, and chlorophyll-a data. The physical environment during the spring sampling was typical of the upwelling period in this region, with a well-defined density front in the shelf-break area and high concentrations of surface chlorophyll-a (>5 mg m⁻³) on the shelf over the Itata terrace. During the winter sampling, highly variable though weakly upwelling-favorable winds were observed along with lower surface chlorophyll-a values (<2 mg m⁻³) on the shelf. In the oceanic area (>100 km from the coast), cyclonic and anti-cyclonic eddies were evident in the flow field during both periods, the former coinciding with higher chlorophyll-a contents (∼1 mg m⁻³) than in the surrounding waters. Also, a cold, chlorophyll-a rich filament was well defined during the spring sampling, extending from the shelf out to 350-400 km offshore. Along a cross-shelf transect, the micro- and meso-planktonic assemblages displayed higher coastal abundances during the spring cruise but secondary peaks appeared in the oceanic area during the winter cruise, coinciding with the distribution of the eddies. These results suggest that the mesoscale features in this region, in combination with upwelling, play a role in potentially increasing the biological productivity of the coastal transition zone off Concepción.  相似文献   

Nanoplanktonic assemblages in the upwelling area off Concepción (∼36°S), central Chile: Abundance, biomass, and grazing potential during the annual cycle     

Daniela Böttjer  Carmen E. Morales 《Progress in Oceanography》2007,75(3):415-434

The structure and functioning of nanoplanktonic assemblages in coastal upwelling areas have usually been overlooked in explorations of the productivity of these areas. As part of a multidisciplinary, time-series station in the coastal area off Concepción, seasonal variations (upwelling and non-upwelling) in the abundance and biomass of these assemblages were investigated. Hydrographic measurements and biological samples were taken monthly over a 2-year period (18 August 2004-28 July 2006). Nanoflagellates dominated the total integrated abundance (3-317 × 10⁹ cells m⁻²; 0-80 m). Diatoms and dinoflagellates usually contributed to a lesser degree (<20%) but sporadically made important contributions to the total integrated nanoplankton biomass (0.02-10.6 g C m⁻²). Most of the nanoplankton was concentrated in surface waters (<30 m) during all the samplings and no seasonal differences in abundance or biomass were found in this layer, although the mean values and dispersions around them were highest during the upwelling period along with maximum integrated (0-80 m) chlorophyll-a values, as total or in the <20 μm fraction. Changes in nanoplankton abundance were significantly but weakly (r < 0.4) correlated with changes in the hydrographic variables; the highest correlation values were positive for temperature and oxygen, factors that varied with depth and date. The potential grazing rates of heterotrophic nano-predators (flagellates and dinoflagellates) on prokaryotic prey, estimated with a generic model, ranged from 3 to 242 bacterioplankton predator⁻¹ h⁻¹ and from 0.1 to 14 cyanobacteria predator⁻¹ h⁻¹. Our results imply a small impact of seasonal hydrographic variability on the abundance and biomass of nanoplanktonic assemblages and suggest that grazing by nanoheterotrophs might control the prokaryotic picoplankton populations in the upwelling area off Concepción.  相似文献   

济州岛附近海域表层沉积物中的颗石及其古海洋学     

程广芬  周颖春 《中国海洋大学学报(自然科学版)》1992,(2)

对济州岛附近海域表层沉积物中的颗石进行研究,共发现40个种。根据对颗石进行多元统计分析的结果,可将本区划为两个环境区、两个颗石组合。提出海流是控制本区颗石分布的主要因素。  相似文献   

Structure of Subsurface Intrusion of the Oyashio Water into the Kuroshio Extension and Formation Process of the North Pacific Intermediate Water     

Kuniaki Okuda  Ichiro Yasuda  Yutaka Hiroe  Yugo Shimizu 《Journal of Oceanography》2001,57(2):121-140

In order to understand the actual formation process of the North Pacific Intermediate Water (NPIW), structure of subsurface intrusions of the Oyashio water and the mixing of the Oyashio and the Kuroshio waters in and around the Kuroshio Extension (KE) were examined on the basis of a synoptic CTD observation carried out in May-June 1992. The fresh Oyashio water in the south of Hokkaido was transported into KE region through the Mixed Water Region (MWR) in the form of subsurface intrusions along two main paths. The one was along the east coast of northern Japan through the First Branch of the Oyashio (FBO) and the other along the eastern face of a warm streamer which connected KE with a warm core ring through the Second Branch of the Oyashio (SBO). The fresh Oyashio water extended southward through FBO strongly mixed with the saline NPIW transported by the Kuroshio in the south of Japan (old NPIW) in and around the warm streamer. On the other hand, the one through SBO well preserved its original properties and extended eastward beyond 150°E along KE with a form of rather narrow band. The intrusion ejected Oyashio water lens with a diameter of 50–60 km southward across KE axis and split northward into the MWR involved in the interaction of KE and a warm core ring, which were supposed to be primary processes of new NPIW formation.  相似文献   

新疆罗布泊地区凝结水试验   总被引：8，自引：1，他引：7  

孙自永  余绍文  周爱国  张俊  刘德良  杨丽 《地质科技情报》2008,27(2):91-96

采用称重法,在高含盐量的罗布泊北部凹地首次进行了凝结水的野外监测,根据监测数据分析了罗布泊地区凝结水的生成规律.研究结果表明罗布泊存在凝结水;2005年7月、10月、12月3次监测时期里日均凝结水量分别为0.293,0.127,0.275 mm;凝结水来源于空气中的水气和深部土壤水分;发生的时间基本在晚上22∶00至次日凌晨8∶00;影响凝结水产生的主要因素为近地面大气温度与地表土壤温度差、空气相对湿度、冻结期等,土壤的高含盐量也有利于凝结水的生成.  相似文献   

Devonian conodonts of the Amur region     

L. P. Eikhvald 《Russian Journal of Pacific Geology》2008,2(3):244-254

  相似文献