2003 Vol. 36 No. 3
2003, 36(3): 1-6.
Abstract：
The volcanic rock association which formed during Sinian to Cambrian period in the Tarim microplate can be divided in to alkaline basalt,tholeiite and rhyolite1 Based on the studying of trace elements and REE geochemical characteristics for the basalt,we have come to some conclusions that the volcanic rocks mainly formed in continental rift valley,but their source region were affected by the contents which derived from the subduction oceanic crust.These geochemical information is significance to discuss about the evolutionary process and the tectonic setting during Sinian to Cambrian period in Tarimarea.
The volcanic rock association which formed during Sinian to Cambrian period in the Tarim microplate can be divided in to alkaline basalt,tholeiite and rhyolite1 Based on the studying of trace elements and REE geochemical characteristics for the basalt,we have come to some conclusions that the volcanic rocks mainly formed in continental rift valley,but their source region were affected by the contents which derived from the subduction oceanic crust.These geochemical information is significance to discuss about the evolutionary process and the tectonic setting during Sinian to Cambrian period in Tarimarea.
Abstract：
The Wenquan granite,which lies in the western Qinling originates,is the product of the magma mixing of crust and mantlemagmas.The host rocks are characterized by higher hypothermal metallogenic elements suchas Mo,Sn,Bi and Was well as siderophile elements Co,Ni and Cr etc.The basic mafic magmatic enclave and basic dyke are rich in LREE and lithophile elements such as Ba,Rb,Sr,Zr,Th,Hf and Nb,but have poorer siderophile elements.The abnormal distribution of the trace elements indicates the noticeably exchanging and complying between the two terminal elements.The ratio of LREE HREE is 10-15 in host rocks,but is 9.98-13.5 in basic parts because of the magm as magm a mixing,namely,they abnormally enrich the LREE.The ratio of the δEu,(La/Sm)N as well as (La/Yb)N all indicate that this rockbody is amigmatized one,and the intensively migmatized monzonitic granite shows the markable transition between crust and mantle.
The Wenquan granite,which lies in the western Qinling originates,is the product of the magma mixing of crust and mantlemagmas.The host rocks are characterized by higher hypothermal metallogenic elements suchas Mo,Sn,Bi and Was well as siderophile elements Co,Ni and Cr etc.The basic mafic magmatic enclave and basic dyke are rich in LREE and lithophile elements such as Ba,Rb,Sr,Zr,Th,Hf and Nb,but have poorer siderophile elements.The abnormal distribution of the trace elements indicates the noticeably exchanging and complying between the two terminal elements.The ratio of LREE HREE is 10-15 in host rocks,but is 9.98-13.5 in basic parts because of the magm as magm a mixing,namely,they abnormally enrich the LREE.The ratio of the δEu,(La/Sm)N as well as (La/Yb)N all indicate that this rockbody is amigmatized one,and the intensively migmatized monzonitic granite shows the markable transition between crust and mantle.
2003, 36(3): 14-23.
Abstract：
The Suwushijie rockbody (group) distributed on the meso-epimetamorphic uplift area of the AZhong massif is a large scale multi-body,and contact relationship between different types of rocks is clear.Their invaded order from early to late is gabbro-diabase → diorite → porphy roid granodiorite → fine granular adamellite → porphyr oid medium-coarse-grained adamellite.As a whole,the characteristics of components and tectonic evaluation have been showed in this order mentioned above.The lithog eochemical data proves that this rock group is similar to SCOLG and shows characteristics of source-mixed granite from mantle source rock and crust source rock.Isotope age indicat es that the invaded age of this group is in late period of Early Paleo zoic and relates to subduction of the subducting plate.
The Suwushijie rockbody (group) distributed on the meso-epimetamorphic uplift area of the AZhong massif is a large scale multi-body,and contact relationship between different types of rocks is clear.Their invaded order from early to late is gabbro-diabase → diorite → porphy roid granodiorite → fine granular adamellite → porphyr oid medium-coarse-grained adamellite.As a whole,the characteristics of components and tectonic evaluation have been showed in this order mentioned above.The lithog eochemical data proves that this rock group is similar to SCOLG and shows characteristics of source-mixed granite from mantle source rock and crust source rock.Isotope age indicat es that the invaded age of this group is in late period of Early Paleo zoic and relates to subduction of the subducting plate.
Abstract：
The ductile shear zone of Huajialing-Huluhe,a disco rdogenic fracture of North Qilian orogenic and median Qilian land mass,is brittle-ductile shear zone with multip eriodic activity,strike NWW.By analyse and research of geomet rics,kinematics,dynamics,etc.We think the deformation peak is convergence coilision of North plate and South plate at late-Caledonian,matching weak continental crust (North Qilian) of south border of North china plate oblique thrusting overlap to median Qilian rigid block at south,soit produced obduction tenacity shear structu refrom NEE to SWW and right-slip.
The ductile shear zone of Huajialing-Huluhe,a disco rdogenic fracture of North Qilian orogenic and median Qilian land mass,is brittle-ductile shear zone with multip eriodic activity,strike NWW.By analyse and research of geomet rics,kinematics,dynamics,etc.We think the deformation peak is convergence coilision of North plate and South plate at late-Caledonian,matching weak continental crust (North Qilian) of south border of North china plate oblique thrusting overlap to median Qilian rigid block at south,soit produced obduction tenacity shear structu refrom NEE to SWW and right-slip.
Abstract：
The oldest loess deposits in Lanzhou area,formed 1.84 Ma.B P ago,was recognized for the first time in the Shanchengwanling Section,Digou village,Yongdeng county,North of Lanzhou.It has eighteen integral sequences of loessp aleosol.The average grain-sizes of loess are 23.57 μm,and of paleosol is 19.10 μm.The loess is composed of siltstone and 90% grass-flower flours in sporo-pollen a ssemblage.On the basis of field survey and indoor systermatic study,the authors summarized the genesis of loess and depositional model,determined the location of up and down siltstone layers through stratigraphic correlation.
The oldest loess deposits in Lanzhou area,formed 1.84 Ma.B P ago,was recognized for the first time in the Shanchengwanling Section,Digou village,Yongdeng county,North of Lanzhou.It has eighteen integral sequences of loessp aleosol.The average grain-sizes of loess are 23.57 μm,and of paleosol is 19.10 μm.The loess is composed of siltstone and 90% grass-flower flours in sporo-pollen a ssemblage.On the basis of field survey and indoor systermatic study,the authors summarized the genesis of loess and depositional model,determined the location of up and down siltstone layers through stratigraphic correlation.
2003, 36(3): 50-56.
Abstract：
The mineral resources related to ophiolite in Daban-Dacha area of North Qilian Mts.,may be divided into the following two series of mineralization: (1) Syngenetic series of mineralization in the ophiolite,i.e.mineral resources assemblage formed along with forming process of the ophiolite suit,magmatogenic chromite ore related to the metamorphic peridotite and hydrothermal massive sulfide copper ore at seafloor was known to us.(2) Epigenetic series of mineralization in the ophiolite,i.e.mineral resources assemblage recom posed after forming process of the ophiolite suit,altered rock type copperore and silver ore in fracture zone was known to us.
The mineral resources related to ophiolite in Daban-Dacha area of North Qilian Mts.,may be divided into the following two series of mineralization: (1) Syngenetic series of mineralization in the ophiolite,i.e.mineral resources assemblage formed along with forming process of the ophiolite suit,magmatogenic chromite ore related to the metamorphic peridotite and hydrothermal massive sulfide copper ore at seafloor was known to us.(2) Epigenetic series of mineralization in the ophiolite,i.e.mineral resources assemblage recom posed after forming process of the ophiolite suit,altered rock type copperore and silver ore in fracture zone was known to us.
2003, 36(3): 57-61.
Abstract：
The Jinwozi gold deposit occurred in Hercynian biotite adamellite and Jingwozi Formation (Upper Devonian).Its mineralization type is the quartz-vein one and the altered-rock one.This study reveals that a granitic magma system,and low-angle ductile-brittle fault and high-angle extension-tension shear second order fault system closely a ssociated with the minerlization in terms of space,time and materials,accounts for the gold minerlizaion.The minerlization types are controlled both by the tectonic stress field and the fracture mechanic property.
The Jinwozi gold deposit occurred in Hercynian biotite adamellite and Jingwozi Formation (Upper Devonian).Its mineralization type is the quartz-vein one and the altered-rock one.This study reveals that a granitic magma system,and low-angle ductile-brittle fault and high-angle extension-tension shear second order fault system closely a ssociated with the minerlization in terms of space,time and materials,accounts for the gold minerlizaion.The minerlization types are controlled both by the tectonic stress field and the fracture mechanic property.
Abstract：
The origins of Chang-6 reservoir horizons in Wangyao district of Ansai oilfield are interp reted to be a river-dom inated delta deposited in lacustrine environm ent.The main sedimentary microfacies of Chang-6 reservoir horizons in Wangyao district include distributary channel,distribu tary mouthbar,front sand sheet and in terdist ributary deposits.The distributary channel fills to show a finning upward sequence.The distributary mouthbar deposits consist of overall coarsing upward sequence and other homogeneous sequences.The distributary channel and distributary mouthbar sands coalesce to constitute the dominated petroleum reservoirs.Prog radation of two distributa ries constructed at first only a delta skeleton in the Chang-612 sand layer.Rapid sed imentation during the period of Chang-611 lead to rapid progradation basinward of multiple distributa ries.The deltaic microfacies are interpreted and delineated based on depositional sequence and sandbody geometry.Sandbody microfacies are the main factors affecting movement of oil and water.Comprehen sive descriptions of sedimentary microfacies are good methods to predict reservoir performance.
The origins of Chang-6 reservoir horizons in Wangyao district of Ansai oilfield are interp reted to be a river-dom inated delta deposited in lacustrine environm ent.The main sedimentary microfacies of Chang-6 reservoir horizons in Wangyao district include distributary channel,distribu tary mouthbar,front sand sheet and in terdist ributary deposits.The distributary channel fills to show a finning upward sequence.The distributary mouthbar deposits consist of overall coarsing upward sequence and other homogeneous sequences.The distributary channel and distributary mouthbar sands coalesce to constitute the dominated petroleum reservoirs.Prog radation of two distributa ries constructed at first only a delta skeleton in the Chang-612 sand layer.Rapid sed imentation during the period of Chang-611 lead to rapid progradation basinward of multiple distributa ries.The deltaic microfacies are interpreted and delineated based on depositional sequence and sandbody geometry.Sandbody microfacies are the main factors affecting movement of oil and water.Comprehen sive descriptions of sedimentary microfacies are good methods to predict reservoir performance.
Abstract：
The sedimentary system and facies typies in the third section of the Paleogene Shahejie Formation of Chang didistrict in the Zhanhua Sag have been studied by using the geolo gical,log,seismic and chemical analysis data.The authors consider that the main type of sedimentary facies was subsurface fan,which can be divided 3 types of subfacieses-root-fan,middle-fan and fan edge.The middle-fan can be divided 3 microf acieses-braided channel,space between channel and front-edge zone.Secondly,rock composition,micro-tex ture of pore,diagenetic stage and hetero geneity of the reservoirs have been systematically studied by comprehensive using granulometric analysis,reservoir capability,mercury penetration analysis,electronic microscope scanning,the digital processed achievements of log data and etc.At last,the authors point out the favorable sand bodies and reser voir beds-the upsides and middle part of the third member of the Shahejie Formation.
The sedimentary system and facies typies in the third section of the Paleogene Shahejie Formation of Chang didistrict in the Zhanhua Sag have been studied by using the geolo gical,log,seismic and chemical analysis data.The authors consider that the main type of sedimentary facies was subsurface fan,which can be divided 3 types of subfacieses-root-fan,middle-fan and fan edge.The middle-fan can be divided 3 microf acieses-braided channel,space between channel and front-edge zone.Secondly,rock composition,micro-tex ture of pore,diagenetic stage and hetero geneity of the reservoirs have been systematically studied by comprehensive using granulometric analysis,reservoir capability,mercury penetration analysis,electronic microscope scanning,the digital processed achievements of log data and etc.At last,the authors point out the favorable sand bodies and reser voir beds-the upsides and middle part of the third member of the Shahejie Formation.
2003, 36(3): 80-84.
Abstract：
It is well known that T3 Chang 2 oil zone exists widely in Ordos basin,they contain industrial oil and some water.The T3 Chang 2 of Zhouhe country of Zhidan county is very different from that of other regions: accor ding to chemical exploration and rock core and interpretation,the oil zone is good,but its out put is poor.Sands distribute widely in these oil well and its thickness is large.The article analyzes clearly the "three-good and one-poor" phenomenon.
It is well known that T3 Chang 2 oil zone exists widely in Ordos basin,they contain industrial oil and some water.The T3 Chang 2 of Zhouhe country of Zhidan county is very different from that of other regions: accor ding to chemical exploration and rock core and interpretation,the oil zone is good,but its out put is poor.Sands distribute widely in these oil well and its thickness is large.The article analyzes clearly the "three-good and one-poor" phenomenon.
Abstract：
The Jurassic coalfield of north Shaanxi,is the largest coalfield probed in China at present.Based on the production and data of regional geological survey in Shenmu area of north Shaanxi with 1:50 000,this paper systemically analyzes the stratig raphic order characteristics of coal-bearing strata in Mesozoic,and the sedimentary patterns in the basin,and the rock-stratum model in this area is established at the first step.Meanw hile this paper reflects the newest progress of the sequence stratigraphic study of the area,and deals with the helpful research on applying the sequence stratigraphy theories to the analysis of the processore-forming and prognostication ore-forming.
The Jurassic coalfield of north Shaanxi,is the largest coalfield probed in China at present.Based on the production and data of regional geological survey in Shenmu area of north Shaanxi with 1:50 000,this paper systemically analyzes the stratig raphic order characteristics of coal-bearing strata in Mesozoic,and the sedimentary patterns in the basin,and the rock-stratum model in this area is established at the first step.Meanw hile this paper reflects the newest progress of the sequence stratigraphic study of the area,and deals with the helpful research on applying the sequence stratigraphy theories to the analysis of the processore-forming and prognostication ore-forming.
Abstract：
The Northwest China covers vastarea with rich in natural resources.They are important bases for sustainable economical development and vital component of development of West China.However,located in arid,semi-arid climate belts,these regions are in short of waterr esources and ecologic environment is fragile.In the last half century,there occurred a series of ecologic environment problems related to water such as soil erosion,land desert ification and secondary salinization due to irrational or over-exploitation of water resources.Aiming at these ecologic environment problems in the regions,the paper presents some counterm easures and preventives steps,which include: water resources should be rationally distributed and planned according to drainage area,ensuring not onl y economical water demand,but keeping ecologic environment from damaging as well; surface reservoirs constructions should be strictly restricted,rather the functions of gobinatural under ground reservoirs ought to be fully taken advant age of; water resources evaluation and managements should be considered together; a detached authoritative organization should be established to manage the water resources uniformly.
The Northwest China covers vastarea with rich in natural resources.They are important bases for sustainable economical development and vital component of development of West China.However,located in arid,semi-arid climate belts,these regions are in short of waterr esources and ecologic environment is fragile.In the last half century,there occurred a series of ecologic environment problems related to water such as soil erosion,land desert ification and secondary salinization due to irrational or over-exploitation of water resources.Aiming at these ecologic environment problems in the regions,the paper presents some counterm easures and preventives steps,which include: water resources should be rationally distributed and planned according to drainage area,ensuring not onl y economical water demand,but keeping ecologic environment from damaging as well; surface reservoirs constructions should be strictly restricted,rather the functions of gobinatural under ground reservoirs ought to be fully taken advant age of; water resources evaluation and managements should be considered together; a detached authoritative organization should be established to manage the water resources uniformly.
2003, 36(3): 97-101.
Abstract：
Mineral resources are very important in the construction of country economy.But environment protection is always ignored in the exploitation of mineral resources in the long-term.This resulted in deteriorating brittle environment of these mines.Inner Mongolia Autonomo us Region is a big province with great mineral resources.And the secondary geologic-environment problems became out standing for the exploitation of mineral resources.These environment problems such as soil desertification,ground collapse,coast slide,debris flow,water pollution,ground water level drop and coal bed self-ignite,can reduce vegetation acreage,destroy the zoology and water environment,pollute air,deteriorate human's living space.A long with the increasing population and demand of mineral resources,we must legislate to mineral geologic-environment protection,investigate and constitute the countermeasure of prevention and curing,reduce geologic disaster.So we can content the contemporary need of mineral resources,and also benefit the off spring in the future.And the aim of sustainable development will cometrue.
Mineral resources are very important in the construction of country economy.But environment protection is always ignored in the exploitation of mineral resources in the long-term.This resulted in deteriorating brittle environment of these mines.Inner Mongolia Autonomo us Region is a big province with great mineral resources.And the secondary geologic-environment problems became out standing for the exploitation of mineral resources.These environment problems such as soil desertification,ground collapse,coast slide,debris flow,water pollution,ground water level drop and coal bed self-ignite,can reduce vegetation acreage,destroy the zoology and water environment,pollute air,deteriorate human's living space.A long with the increasing population and demand of mineral resources,we must legislate to mineral geologic-environment protection,investigate and constitute the countermeasure of prevention and curing,reduce geologic disaster.So we can content the contemporary need of mineral resources,and also benefit the off spring in the future.And the aim of sustainable development will cometrue.
2003, 36(3): 102-105.
Abstract：
The soft soil's property of the area where the expressway is passed in Nantong-Haimen is analyzed in particular.At the same time,the regression equation between the physical index and the mechanical index is establ ished by the geomathematics method.At last,according to engineering practice,the soft's allowable bearing capacity is put forward.
The soft soil's property of the area where the expressway is passed in Nantong-Haimen is analyzed in particular.At the same time,the regression equation between the physical index and the mechanical index is establ ished by the geomathematics method.At last,according to engineering practice,the soft's allowable bearing capacity is put forward.
2003, 36(3): 106-110.
Abstract：
The Hukou waterfall of the Yellow river which lies in the meeting belt between Shaanxi and Shanxi provinces has been approved to be the National Geopark.Based on the analyzing of the characters and the cause of formation of Hukouwaterfall,the tactics of protective development are proposed in order to realize the susta inable utilizing of it.
The Hukou waterfall of the Yellow river which lies in the meeting belt between Shaanxi and Shanxi provinces has been approved to be the National Geopark.Based on the analyzing of the characters and the cause of formation of Hukouwaterfall,the tactics of protective development are proposed in order to realize the susta inable utilizing of it.
Abstract：
The paper analyzed geology and topography,as well as climate in Gansu Province in detail and divided Gansu into 6 geochemical landscapes on the basis of summarizing working methods of region geochemistry in 20 years in Gansu Bureau of Geological and Mineral.Through making statistic to working methods of region geochemistry past and analyzing data in existence and summarizing effect of looking for mine approx imately,we think working methods of region geochemistry of the 5 geochemical landscapes have more or less errors except sout heast Gansu Province,which is to be studied further.
The paper analyzed geology and topography,as well as climate in Gansu Province in detail and divided Gansu into 6 geochemical landscapes on the basis of summarizing working methods of region geochemistry in 20 years in Gansu Bureau of Geological and Mineral.Through making statistic to working methods of region geochemistry past and analyzing data in existence and summarizing effect of looking for mine approx imately,we think working methods of region geochemistry of the 5 geochemical landscapes have more or less errors except sout heast Gansu Province,which is to be studied further.
