秦岭-大别山壳幔岩石高温高压下的电性特征   总被引：6，自引：0，他引：6       下载免费PDF全文

高平  杨僻元 《地质科学》1998,33(2):195-203

首次报导了秦岭-大别山壳幔岩石高温高压下电导率的测定结果。该区中上地壳主要代表岩石(角闪岩、绢云母石英片岩、千枚岩等)在10^-25km的温压条件下,含水矿物出现脱水会引起电导率值升高,认为这是该区出现高导层体的主要原因;中下地壳代表性岩石(片麻岩、麻粒岩、榴辉岩等)由于石英从α相向β相转变,会导致电导率值(σ)下降。在下地壳的温压条件下电导率值一般为10^-2到10^-3S·m^-1;上地幔的代表性岩石由于组成矿物较为基性,电导率值比下地壳高,从0.1到1S·m^-1。  相似文献   

Crabs,leeches and trypanosomes: an unholy trinity?     

Hemmingsen W  Jansen PA  Mackenzie K 《Marine pollution bulletin》2005,50(3):336-339

The red king crab Paralithodes camtschaticus was deliberately introduced to the Barents Sea in the 1960s and 1970s from its native area in the North Pacific. The carapace of these crabs is a favoured substrate for the leech Johanssonia arctica to deposit its eggs, and the leech is a vector for a trypanosome blood parasite of marine fish, including cod. We examined cod for trypanosome infections during annual cruises along the coast of Finnmark in North Norway over three successive years from stations along a gradient of over 1000 km. In every year the level of trypanosome infection in cod was significantly highest in the area with the greatest density of king crabs. We propose the hypothesis that the burgeoning population of red king crabs in this area is indirectly responsible for increased transmission of trypanosomes to cod by promoting an increase in the population of the leech vector.  相似文献   

Sediment records of past anthropogenic environmental changes in a barrier reef lagoon (Papeete, Tahiti, French Polynesia)     

Fichez R  Harris PA  Fernandez JM  Chevillon C  Badie C 《Marine pollution bulletin》2005,50(5):599-608

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討論囘答之三     

高平  陳國達 《地质论评》1940,5(6):560-562

甲、關淤圖幅分法問題 所提按經緯度分幅,法至完善。本所測製江西地質圖之初,亦會顧及。惟因此點在野外工作時,兩組人員調查區域界限不易確定,不得已乃改依陸地测量局原圖分幅。此點困難,似  相似文献   

PRELIMINARY NOTES ON SINIAN STRATIGRAPHY OF NORTH CHINA     

高振西  熊永先  高平 《地质学报》1934,(0)

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水对岩石变形过程中电阻率变化的影响   总被引：5，自引：0，他引：5  

张流  黄建国  高平 《地震》2003,23(1):8-14

实验研究表明: 在变形破坏过程中, 干燥砂岩电阻率略有下降, 变化幅度小; 少量含水的砂岩电阻率下降幅度大; 含水量多的砂岩电阻率有下降-上升-下降的变化, 变化幅度又小;而完全水饱和的砂岩除初期电阻率有所下降外, 变化更小。更精确的观察表明: 干燥砂岩, 破裂前电阻率有升高的迹象; 少量含水的样品, 破裂前电阻率单调下降; 含水量较多和水饱和的样品, 破裂前电阻率有先升高后降低的变化。这些有可能给出中短期前兆特征的提示。对电阻率变化的机理给出了解释。  相似文献   

Crystal Structure and Chemical Composition of Ludwigite from Vranovac Ore Deposit (Boranja Mountain,Serbia)     

Pavle TAN?I?  Radovan DIMITRIJEVI?  Maja POZNANOVI?  Aleksandar PA?EVSKI  Slobodanka SUDAR 《《地质学报》英文版》2012,86(6):1524-1538

The crystal structure of ludwigite from Vranovac ore deposit (Boranja Mt., Serbia) was refined using the X-ray powder diffraction (XRPD) Rietveld method in the space group Pbam to a final RB=7.45% and RF=5.26%. It has the unit cell dimensions of: a=9.2515(2) ?; b=12.3109(2) ?; c=3.03712(7) ?; and V=345.91(1) ?3. The calculated distances and angles are mostly in good agreement with the Mg2+-Fe2+ substitutions across the M(1) and M(3) sites, as well as with the Fe3+-Al3+ replacement in the M(4) site. However, the mean observed M(2)-O distance is considerably shorter than prescribed, due to a slight increase of the Fe3+ content in the M(2) site. Such replacement was compensated by slight increase of the Fe2+ content in the M(4) site, resulting in the (Mg1.48Fe2+0.46Fe3+0.05Mn0.02)2.01(Fe3+0.94Fe2+0.04Al0.02)1.00B1.00O5 composition. The formation temperature was estimated to be about 500–600°C. The influences of the various chemical compositions to the crystallographic parameters, M-O distances, M(3) and M(4) sites shift, distortion parameters and estimated valences, were also studied and compared with other reference samples.  相似文献   

基于C#和SharpMap 的浅层地温能资源数据库管理系统研究和开发     

方静涛  张延军  黄贤龙  高平  孙永泉 《世界地质》2012,31(3):608-613

通过对数据库管理系统开发研究,将其应用到XX 地区浅层地温能资源数据库管理系统开发实际工程。根据浅层地温能资源数据库管理系统功能需求的分析,以Microsoft Visual Studio 2008 作为系统界面可视化的开发平台,以C#为开发语言,引用开源的SharpMap 作为地图编辑操作的GIS 工具,实现系统的各个功能。该系统为全面了解XX 地区浅层地热能资源赋存情况提供了工具,对合理规划、开发、利用和管理该地区浅层地热能有极大帮助。  相似文献   

Bacterial contribution to mitigation of iron and manganese in mangrove sediments   总被引：1，自引：0，他引：1  

Krishnan KP  Fernandes SO  Chandan GS  Loka Bharathi PA 《Marine pollution bulletin》2007,54(9):1427-1433

The Mandovi and Chapora are two tropical estuaries lying in close geographic proximity on the west coast of India. Seasonal changes in down core variation of Fe, Mn and Total Organic Carbon (TOC) in the mangrove sediments adjoining these estuaries were studied to assess their influence on some of the representative benthic bacteria belonging to heterotrophic and autotrophic groups. Heterotrophic bacteria (HB) cultured on different nutrient concentrations (0.01%, 0.1% and 25%) together with nitrifiers (NtB; representating autotroph) were chosen to assess the influence of the above-mentioned abiotic parameters on the former. The experimental site located along the Mandovi is under the influence of extensive ferromanganese ore mining, while the control site at Chapora is relatively free from such influences. Geoaccumulation index computed for Mandovi showed that sediments (0-10cm) were 'uncontaminated to moderately contaminated' by Fe during the pre monsoon and monsoon seasons, while in the post monsoon season the 4-10cm fraction was almost completely restored from contamination. Similar computations for Mn showed that in pre monsoon, sediments fell in the 'moderately contaminated' and 'moderately to strongly contaminated' categories, while in the monsoon and post monsoon seasons all the sections were 'Uncontaminated'. The difference observed in correlation between Fe and Mn with the various fractions of heterotrophs and nitrifiers indicated that though these two elements shared a similar chemistry in the environment, microbes involved in biogeochemical processes might prefer them differentially. The relationship between TOC and HB enumerated on 0.01% dilute nutrient agar remained at r=0.50, p<0.05 throughout the year. Hence, it could be apparently linked to their preferred concentration of organic carbon requirement. A relationship of r=0.61, p<0.01 between manganese concentration and heterotrophs recovered on different strengths of nutrient agar is suggestive of their response to the metal enrichment. They could thus contribute towards maintaining the level of Mn at par with reference levels at Chapora. A positive correlation between Mn with NtB (n=10, p<0.05, r=0.58) at the experimental site during the non-monsoon months is suggestive of the latter's contribution to regulation of the metal concentration in the sediment probably through anaerobic nitrification at the expense of manganese. The study therefore supports our hypothesis that both autochthonous autotrophs and heterotrophs work in tandem to mitigate concentration of Mn and related metals in mangrove sediments.  相似文献   

An investigation into intersex amphipods and a possible association with aquaculture     

Ford AT  Read PA  Jones TL  Michino F  Pang Y  Fernandes TF 《Marine environmental research》2007,64(4):443-455

The amphipod, Echinogammarus marinus, is common in sheltered coastal inlets, such as estuaries and sea lochs, in Scotland and exhibits increased levels of intersex in some contaminated areas. Sea lochs are commonly the location for coastal aquaculture development, and some chemicals used in fish-farming are specifically designed to target the crustacean nervous system. Therefore it was hypothesised that these chemicals may also affect neuro-endocrine pathways, causing morphological and reproductive abnormalities in non-target Crustacea. Based upon this hypothesis, Echinogammarus marinus amphipods from two different Scottish sea lochs containing salmon farms were investigated. Morphology, intersexuality, and the incidence of microsporidian parasites were recorded at sites close and at distance from fish-farms. Results suggest a higher incidence of intersexuality at sites within sea lochs, comparable to that observed in industrially contaminated sites elsewhere in Scotland. The data suggest that fish farming activity may influence the observed distributions of intersexuality within lochs. Intersex specimens were more likely to be infected by microsporidian parasites than non-intersex specimens. Normal females were found more likely to be infected by microsporidian parasites at sites associated with high intersexuality, suggesting the parasite as the probable feminiser. The cause(s) for the observed patterns of intersexuality are unclear, although suggestions relating to discharges from fish farms are discussed.  相似文献