The Miocene molassic Surma sandstones in parts of the Naga-Manipur hills,in and around Nungba,Northeast India have been studied for their tectonic provenance using petrography and heavy mineral contents.The poorly-to-...The Miocene molassic Surma sandstones in parts of the Naga-Manipur hills,in and around Nungba,Northeast India have been studied for their tectonic provenance using petrography and heavy mineral contents.The poorly-to-moderately-sorted sub-litharenite to lithicarkose type Surma sandstones display predominance of monocrystalline quartz(av.61%)and include undulose and non-undulose varieties and almost equal amounts of feldspars(av.22%)and rock fragments(av.17%).The heavy mineral suite of Surma sandstones is dominated by transparent varieties(96%)that include garnet,zircon,tourmaline,rutile,staurolite,scapolite,phlogopite,chondrodite,humite,wollastonite,hedenbergite,sphene,chlorite,sillimanite,glauconite,glaucophane,and chloritoid.These heavy minerals characterize the granitic and silicic metamorphic complexes(GM)as well as the basic metamorphic rocks(MT)like greenstones,green schist,and amphibolites relating to passive continental margin setup.The opaque grains constitute nearly 4%of the total heavy minerals.The presence of euhedral,as well as abraded heavy mineral grains,further supports a mixed provenance having substantial contribution from sedimentary and metamorphic rocks.A ZTR index of approximately 45%indicates mineralogically sub-mature nature of Surma sandstones.Based on the light and heavy mineral suites coupled with the type of terrain available in the vicinity of the study area,it may be visualized that the sediment supply was largely made by the Himalaya,the IMR,the Shillong plateau,and the Mikir Hills under the influence of semi-arid to semi-humid climatic conditions.An overall supply from a recycled orogen provenance has been envisaged.展开更多
Through petroleum exploration of 20 years, a new petroleum production area has been constructed in Hailar Basin. Their petroleum geological characteristics and hydrocarbon distribution has been known in detail. The Ha...Through petroleum exploration of 20 years, a new petroleum production area has been constructed in Hailar Basin. Their petroleum geological characteristics and hydrocarbon distribution has been known in detail. The Hailar Basin is a basin group consisted of many scattered sub-basins with similar structural developed history. Each sub-basin has unique hydrocarbon distributing rules, including (1) oil/gas reservoir distribution is controlled by the oil/gas sag, and the oil/gas bearing in big sag is rich; (2) underwater fan and turbidity fan are the most favorable reservoirs; structure zone controlled by main fault is favorable zone of forming composite oil/gas accumulation; (3) lower fault-block in higher rise and higher fault-block in lower rise are favorable to oil/gas accumulation; (4) deep fault and granite body are closely re-lated to oil/gas reservoir, its distributing area is favorable area of oil and mantle source non-hydrocarbon gas formation; (5) higher geothermal area is favorable oil/gas bearing area.展开更多
Based on the analyses of grouped activity features of deep-focus (M≥6.0) and shallow-focus (M S≥5.0) earthquakes in the Northeast China region, the time-space correlation between deep focus “strong earthquake group...Based on the analyses of grouped activity features of deep-focus (M≥6.0) and shallow-focus (M S≥5.0) earthquakes in the Northeast China region, the time-space correlation between deep focus “strong earthquake group" and shallow focus “strong earthquake group" have been studied. The study was mainly on the characteristics of earthquake distribution on the collision zone between the west Pacific plate and the Eurasian plate and on its relations to the morphological feature of the western Pacific subduction zone. Moreover, emphasis was laid on analysis of the effect of the west Pacific plate on the seismicity of Eurasian plate. It is shown that in the region where the west Pacific plate subducts at low angles, the seismicity on the plate collision zone is strong, the effect of plate subduction on Eurasian continent is strong too, and the subduction zone is under a state of high compressional stress. However, in the region where the west Pacific plate subducts at high angles, the seismicity along the plate collision zone is weak, the effect of plate subduction on Eurasian continent is weak too, and the tensile stress produced by the subduction zone at depth is enhanced. We therefore propose that the seismicity in the northeast China region will enter an active period of shallow “strong earthquake group" in the future 10 years. In the period, six earthquakes of M S≥5.0 may occur. Therefore, the work of earthquake monitoring and prediction in this region shall be strengthened.展开更多
基金funding the research programme through Inspire Fellowship No. IF140996
文摘The Miocene molassic Surma sandstones in parts of the Naga-Manipur hills,in and around Nungba,Northeast India have been studied for their tectonic provenance using petrography and heavy mineral contents.The poorly-to-moderately-sorted sub-litharenite to lithicarkose type Surma sandstones display predominance of monocrystalline quartz(av.61%)and include undulose and non-undulose varieties and almost equal amounts of feldspars(av.22%)and rock fragments(av.17%).The heavy mineral suite of Surma sandstones is dominated by transparent varieties(96%)that include garnet,zircon,tourmaline,rutile,staurolite,scapolite,phlogopite,chondrodite,humite,wollastonite,hedenbergite,sphene,chlorite,sillimanite,glauconite,glaucophane,and chloritoid.These heavy minerals characterize the granitic and silicic metamorphic complexes(GM)as well as the basic metamorphic rocks(MT)like greenstones,green schist,and amphibolites relating to passive continental margin setup.The opaque grains constitute nearly 4%of the total heavy minerals.The presence of euhedral,as well as abraded heavy mineral grains,further supports a mixed provenance having substantial contribution from sedimentary and metamorphic rocks.A ZTR index of approximately 45%indicates mineralogically sub-mature nature of Surma sandstones.Based on the light and heavy mineral suites coupled with the type of terrain available in the vicinity of the study area,it may be visualized that the sediment supply was largely made by the Himalaya,the IMR,the Shillong plateau,and the Mikir Hills under the influence of semi-arid to semi-humid climatic conditions.An overall supply from a recycled orogen provenance has been envisaged.
文摘Through petroleum exploration of 20 years, a new petroleum production area has been constructed in Hailar Basin. Their petroleum geological characteristics and hydrocarbon distribution has been known in detail. The Hailar Basin is a basin group consisted of many scattered sub-basins with similar structural developed history. Each sub-basin has unique hydrocarbon distributing rules, including (1) oil/gas reservoir distribution is controlled by the oil/gas sag, and the oil/gas bearing in big sag is rich; (2) underwater fan and turbidity fan are the most favorable reservoirs; structure zone controlled by main fault is favorable zone of forming composite oil/gas accumulation; (3) lower fault-block in higher rise and higher fault-block in lower rise are favorable to oil/gas accumulation; (4) deep fault and granite body are closely re-lated to oil/gas reservoir, its distributing area is favorable area of oil and mantle source non-hydrocarbon gas formation; (5) higher geothermal area is favorable oil/gas bearing area.
文摘Based on the analyses of grouped activity features of deep-focus (M≥6.0) and shallow-focus (M S≥5.0) earthquakes in the Northeast China region, the time-space correlation between deep focus “strong earthquake group" and shallow focus “strong earthquake group" have been studied. The study was mainly on the characteristics of earthquake distribution on the collision zone between the west Pacific plate and the Eurasian plate and on its relations to the morphological feature of the western Pacific subduction zone. Moreover, emphasis was laid on analysis of the effect of the west Pacific plate on the seismicity of Eurasian plate. It is shown that in the region where the west Pacific plate subducts at low angles, the seismicity on the plate collision zone is strong, the effect of plate subduction on Eurasian continent is strong too, and the subduction zone is under a state of high compressional stress. However, in the region where the west Pacific plate subducts at high angles, the seismicity along the plate collision zone is weak, the effect of plate subduction on Eurasian continent is weak too, and the tensile stress produced by the subduction zone at depth is enhanced. We therefore propose that the seismicity in the northeast China region will enter an active period of shallow “strong earthquake group" in the future 10 years. In the period, six earthquakes of M S≥5.0 may occur. Therefore, the work of earthquake monitoring and prediction in this region shall be strengthened.
