Rhenium (Re)–Osmium (Os) geochronology of the Proterozoic Sirban Limestone Formation,NW Himalaya     

Naveen Hakhoo  Bindra Thusu  Ghulam M. Bhat  Jonathan Craig  Juergen Thurow  Mateen Hafiz 《Journal of the Geological Society of India》2016,88(3):267-272

The Proterozoic Sirban Limestone Formation (SLFm) exposed in a number of inliers in Jammu (India), NW Himalaya is a potential target for hydrocarbon and ore mineral exploration. The structural complexity not only makes correlation of the SLFm with coeval hydrocarbon producing Proterozoic formations in the neighbouring Salt Range in Pakistan and elsewhere in the world extremely difficult, but also limits the understanding of the genesis of sedimentary hosted mineral deposits. The base of the SLFm inliers is not exposed anywhere in the region and the age of this sequence has been suggested to range from Palaeoproterozoic to Neoproterozoic.  相似文献   

When and why the continental crust is subducted: Examples of Hindu Kush and Burma     

Tetsuzo Seno  Hafiz Ur Rehman 《Gondwana Research》2011,19(1):327-333

The Indian subcontinent has been colliding against Asia along the Himalayas. Hindu Kush and Burma in this collision zone have intermediate-depth seismicities beneath them, with most of the continental crust subducted into a few hundred km depth. The subduction, not collision, in these regions is an enigma long time. We show that the continental lithosphere subducted beneath Hindu Kush and Burma traveled over the Reunion and Kerguelen hotspots from 100 Ma to 126 Ma and is likely to have been metasomatized by upwelling plumes beneath those hotspots. The devolatilization of the metasomatized lithosphere impinging on the collision boundary would have provided a high pore fluid pressure ratio at the thrust zones and made the subduction of the continental lithosphere in these regions possible. The subducted lithosphere could give intermediate-depth seismicities by devolatilization embrittlement. Such subduction of hotspot-affected lithosphere without accompanying any oceanic plate would be one candidate for producing ultrahigh-pressure metamorphic rocks by deep subduction of the continental crust.  相似文献   

Toxic hexavalent chromium reduction by Bacillus pumilis,Cellulosimicrobium cellulans and Exiguobacterium   总被引：1，自引：0，他引：1  

Fatima Rehman  Muhammad Faisal 《中国海洋湖沼学报》2015,33(3):585-589

Three bacterial strains B acillus pumilis,Cellulosimicrobium cellulans and Exiguobacterium were investigated when grown in Luria-Bertani(LB) medium at 500 μg/m L Cr(VI). The hexavalent chromium reduction was measured by growing the strains in De Leo and Ehrlich(1994) medium at 200 and 400 μg/m L K 2 Cr O 4. The optimal Cr(VI) reduction by strains B. pumilis,Exigubacterium and C. cellulans was 51%,39%,and 41%,respectively,at an initial K2 Cr O 4 concentration of 200 μg/m L at p H 3 and temperature 37°C. At an initial chromate concentration of 400 μg/m L,the Cr(VI) reduction by strains B. pumilis,Exigubacterium and C. cellulans was 24%,19%,and 18%,respectively at p H 3 at 37°C after 24 h. These strains have ability to reduce toxic hexavalent chromium to the less mobile trivalent chromium at a wide range of different environmental conditions and can be useful for the treatment of contaminated wastewater and soils.  相似文献   

Threat of glacial lake outburst flood to Tehsil Gupis from Khukush Lake, District Ghizer, Gilgit Baltistan, Pakistan     

Gohar Rehman  Sajjad Ahmad  Shuhab D. Khan  Fayaz Ali  Taqweemul H. Ali  Sadaf F. Khan 《Natural Hazards》2014,70(2):1589-1602

Glacial lake outburst flood (GLOF) is a powerful natural phenomenon that is very active in the Karakoram and Himalayas. This paper presents a case study from Gupis Tehsil in northern areas of Pakistan that is exposed to GLOFs from nine different glacial lakes in its upper catchment areas. Khukush Lake being the largest of all the glacial lakes has been studied and a flood attenuation model has been created for the whole Gupis Tehsil. This lake covers almost 2.2 km² of surface area, and its calculated volume is 2.6 × 10⁴ m³. In case of its outburst, the peak flow discharge is calculated to be 7,642 m³/s. The catchment area which contributes water and debris to the lake is 170 km². This lake is dammed by a glacial moraine, which is not strong enough to sustain the pressure for a longer period of time. Other factors that are reducing the reliability of the dam are the secondary hazards which are in direct contact with the lake, and in case of their reactivation, they can put severe impacts on the dam. There are eight potential sites of the snow avalanche activity where debris along with snow may fall directly into the lake producing a strong wave. This strong wave of water will increase the pressure on the dam and ultimately will increase the probability for its outburst. The presense of water springs towards the downstream side of the natural dam also indicate the presence of hidden channels passing through the dam which may weaken the shear strength of the dam. Almost 24 villages settled along either sides of the Gupis River are critically studied for the expected flood from Khukush Lake. With few exceptions, almost 20–25 % area of all the villages will be affected from this flood.  相似文献   

变质矿床的成因分类     

IO.M.索柯洛夫  M.E.萨利耶 《吉林大学学报(地球科学版)》1993,(1)

本文溯本求源,讨论了变质成矿作用学说的建立、变质作用及变质成矿作用研究的几个历史阶段和现状,对以往的变质矿床分类做了分析,论证了本分类的理论前提,在该分类中划分出前变质、流变质(peo-)①和正变质矿床。  相似文献   

Depositional Environment and Lithofacies Analyses of Eocene Lacustrine Shale in the Bohai Bay Basin: Insights from Mineralogy and Elemental Geochemistry          下载免费PDF全文

Danish KHAN  LIANG Chao  QIU Longwei  Kamran MIRZA  WANG Yelei  Muhammad KASHIF  Saif Ur REHMAN  WANG Yuzhe  TENG Jianbin 《《地质学报》英文版》2023,97(2):589-609

The effect of various depositional parameters including paleoclimate, paleosalinity and provenance, on the depositional mechanism of lacustrine shale is very important in reconstructing the depositional environment. The classification of shale lithofacies and the interpretation of shale depositional environment are key features used in shale oil and gas exploration and development activity. The lower 3^rd member of the Eocene Shahejie Formation(Es₃^x shale) was sel...  相似文献   

K-means cluster analysis and seismicity partitioning for Pakistan   总被引：2，自引：2，他引：0  

Khaista Rehman  Paul W. Burton  Graeme A. Weatherill 《Journal of Seismology》2014,18(3):401-419

Pakistan and the western Himalaya is a region of high seismic activity located at the triple junction between the Arabian, Eurasian and Indian plates. Four devastating earthquakes have resulted in significant numbers of fatalities in Pakistan and the surrounding region in the past century (Quetta, 1935; Makran, 1945; Pattan, 1974 and the recent 2005 Kashmir earthquake). It is therefore necessary to develop an understanding of the spatial distribution of seismicity and the potential seismogenic sources across the region. This forms an important basis for the calculation of seismic hazard; a crucial input in seismic design codes needed to begin to effectively mitigate the high earthquake risk in Pakistan. The development of seismogenic source zones for seismic hazard analysis is driven by both geological and seismotectonic inputs. Despite the many developments in seismic hazard in recent decades, the manner in which seismotectonic information feeds the definition of the seismic source can, in many parts of the world including Pakistan and the surrounding regions, remain a subjective process driven primarily by expert judgment. Whilst much research is ongoing to map and characterise active faults in Pakistan, knowledge of the seismogenic properties of the active faults is still incomplete in much of the region. Consequently, seismicity, both historical and instrumental, remains a primary guide to the seismogenic sources of Pakistan. This study utilises a cluster analysis approach for the purposes of identifying spatial differences in seismicity, which can be utilised to form a basis for delineating seismogenic source regions. An effort is made to examine seismicity partitioning for Pakistan with respect to earthquake database, seismic cluster analysis and seismic partitions in a seismic hazard context. A magnitude homogenous earthquake catalogue has been compiled using various available earthquake data. The earthquake catalogue covers a time span from 1930 to 2007 and an area from 23.00° to 39.00°N and 59.00° to 80.00°E. A threshold magnitude of 5.2 is considered for K-means cluster analysis. The current study uses the traditional metrics of cluster quality, in addition to a seismic hazard contextual metric to attempt to constrain the preferred number of clusters found in the data. The spatial distribution of earthquakes from the catalogue was used to define the seismic clusters for Pakistan, which can be used further in the process of defining seismogenic sources and corresponding earthquake recurrence models for estimates of seismic hazard and risk in Pakistan. Consideration of the different approaches to cluster validation in a seismic hazard context suggests that Pakistan may be divided into K?=?19 seismic clusters, including some portions of the neighbouring countries of Afghanistan, Tajikistan and India.  相似文献   

High Ni Levels in Soil Can Modify Growth Performance and Mineral Status of Wheat Cultivars          下载免费PDF全文

Muhammad Sabir  Khalid Rehman Hakeem  Tariq Aziz  Muhammad Zia‐ur‐Rehman  Irfan Rashid  Munir Ozturk 《洁净——土壤、空气、水》2014,42(9):1263-1271

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Kinetics and Thermodynamic Studies of Oxytetracycline Mineralization Using UV/H2O2          下载免费PDF全文

Anisa Ur Rahmah  Sabtanti Harimurti  Abdul Aziz Omar  Thanapalan Murugesan 《洁净——土壤、空气、水》2015,43(4):496-503

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Alleviating Effect of Calcium on Nickel Toxicity in Rice          下载免费PDF全文

Humera Aziz  Muhammad Sabir  Hamaad Raza Ahmad  Tariq Aziz  Muhammad Zia‐ur‐Rehman  Khalid Rehman Hakeem  Munir Ozturk 《洁净——土壤、空气、水》2015,43(6):901-909

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