2003 Vol. 36 No. 2
Abstract：
According to a great deal of data measured practically in the typical area of the Yellow River valley from Gonghe to Lanzhou, and refering to the research results before, we propose that the valley landforms is formed by tectonic process under some conditions, and up lift rate of the valley landforms reflects two new tectonic events: one from 0.2 MaB.P.to 0.15 MaB.P.,and another from 0.01 MaB.P.to present.Since Quaternary, directing to northeast, the gradual reduction stress is indicated by the longitudinal section of the Yellow River terrace in Qinghai-Xizang plateau, the stress is disappeared in some period in Lanzhou.
According to a great deal of data measured practically in the typical area of the Yellow River valley from Gonghe to Lanzhou, and refering to the research results before, we propose that the valley landforms is formed by tectonic process under some conditions, and up lift rate of the valley landforms reflects two new tectonic events: one from 0.2 MaB.P.to 0.15 MaB.P.,and another from 0.01 MaB.P.to present.Since Quaternary, directing to northeast, the gradual reduction stress is indicated by the longitudinal section of the Yellow River terrace in Qinghai-Xizang plateau, the stress is disappeared in some period in Lanzhou.
Abstract：
Based on the analysis for the state in the research of adakite in China, this paper discusses the major advances in the research of adakite, and probes in to the particular geodynamic significances that are less or out of noticed before.This paper emphasizes that O-type adakite may be as an indicator to reveal the start of oceanic shrink and subduction, whereas the C-type adakite maybe indicate that the crust has thickened before the forming of this kind of magma.And then, the authors point out that many problems of adakite may be resolved by studying the adakite in Tibetan Plateau.
Based on the analysis for the state in the research of adakite in China, this paper discusses the major advances in the research of adakite, and probes in to the particular geodynamic significances that are less or out of noticed before.This paper emphasizes that O-type adakite may be as an indicator to reveal the start of oceanic shrink and subduction, whereas the C-type adakite maybe indicate that the crust has thickened before the forming of this kind of magma.And then, the authors point out that many problems of adakite may be resolved by studying the adakite in Tibetan Plateau.
Abstract：
The ophiolite tectonic mixtite belt from Qingshuiquan to Mangnai, appearing strike "green belt", distributed on the south slope of Altgn Tagh.And it is composed of ophiolite, overlying rock series with ocean deep-sea desposit characteristics and exotic block, which are tectonic lens now.The lithochemistry data testify that basalt in ophiolite is similar to ocean inner arc tholeiite.Results of isotopic age prove that this ophiolite was formed in the Early Paleozoic and originated from depletion flow agesphere mantle and the enrichment mental matter joined at the same time.They imply survey area is ever a small ocean basin.
The ophiolite tectonic mixtite belt from Qingshuiquan to Mangnai, appearing strike "green belt", distributed on the south slope of Altgn Tagh.And it is composed of ophiolite, overlying rock series with ocean deep-sea desposit characteristics and exotic block, which are tectonic lens now.The lithochemistry data testify that basalt in ophiolite is similar to ocean inner arc tholeiite.Results of isotopic age prove that this ophiolite was formed in the Early Paleozoic and originated from depletion flow agesphere mantle and the enrichment mental matter joined at the same time.They imply survey area is ever a small ocean basin.
2003, 36(2): 30-34.
Abstract：
The metamorphic core complex of Lebaquan is formed at multiple stage extensional structure system, and is characterized by a three-layer texture: crystalline basement, middle shear cover-layer and upper brittle cover-layer.And the three layers are divided by basement denudational fault and cover-layer denudational fault.The paper mainly deals with material formation, texture and typical tectonic style, and analyses the formation age and tectoncs background.
The metamorphic core complex of Lebaquan is formed at multiple stage extensional structure system, and is characterized by a three-layer texture: crystalline basement, middle shear cover-layer and upper brittle cover-layer.And the three layers are divided by basement denudational fault and cover-layer denudational fault.The paper mainly deals with material formation, texture and typical tectonic style, and analyses the formation age and tectoncs background.
2003, 36(2): 35-42.
Abstract：
Volcanic rocks of mesozoic were widely distributed in Western Liaoning province.Yixian volcanic Cycle of early Cretaceous is divided into four subcycles.From early to late, the magma of Yixian volcanic cycle evolved gradually from basic, inter mediate-basic and intermediate to acidic.The ∑REE of volcanic rocks of Yixian volcanic cycle is high and rich in LREE.The spider patterns are the right-incline and there is a slight low Eunegative abnormality and low Ce postive abnormality.REE characteristics show that volcanic rocks of Yixian volcanic cycle were generated in responsing to lithosphere extension in the continent intraplate orogenic belt.The lithogenesis take partial melting as a major part.
Volcanic rocks of mesozoic were widely distributed in Western Liaoning province.Yixian volcanic Cycle of early Cretaceous is divided into four subcycles.From early to late, the magma of Yixian volcanic cycle evolved gradually from basic, inter mediate-basic and intermediate to acidic.The ∑REE of volcanic rocks of Yixian volcanic cycle is high and rich in LREE.The spider patterns are the right-incline and there is a slight low Eunegative abnormality and low Ce postive abnormality.REE characteristics show that volcanic rocks of Yixian volcanic cycle were generated in responsing to lithosphere extension in the continent intraplate orogenic belt.The lithogenesis take partial melting as a major part.
Abstract：
The characteristics of fluid inclusion in Dashankou gold deposit, Xinjiang, belong to K+-Na+-SO42--Cl--CO2 type.The salinity and density are all low degree.The ore-forming temperature of No.1 stage is 219.92℃ with pressure 22.14×105 Pa, and the main ore-forming stage is 298.28℃ with pressure 27.98×105 Pa.Thus the deposit belongs to low-middle temperature system.The fluid origenates mainly from magmatic water, or may be mixed with a small quatity of other source of waters.The gold deposit belongs to poor-sulfide type gold deposit and is controled by shear zone.
The characteristics of fluid inclusion in Dashankou gold deposit, Xinjiang, belong to K+-Na+-SO42--Cl--CO2 type.The salinity and density are all low degree.The ore-forming temperature of No.1 stage is 219.92℃ with pressure 22.14×105 Pa, and the main ore-forming stage is 298.28℃ with pressure 27.98×105 Pa.Thus the deposit belongs to low-middle temperature system.The fluid origenates mainly from magmatic water, or may be mixed with a small quatity of other source of waters.The gold deposit belongs to poor-sulfide type gold deposit and is controled by shear zone.
Abstract：
Axi gold deposit and its peripheral ore deposits Yierm ande, Qiabukanzuota, which formed in Late Paleozoic volcanic rocks in West Tianshan Mountains, are considered as epithermal mineralizing type, and divided furtherly in to adular-sericite type and silicated rock type.The gold deposits are formed in Tulasu-Yelimodun volcanic belt of Yili Late Paleozoic rift.And the country rocks of the gold deposit are continental in termediate-acid volcanic eruptive rock series of Dahalajunshan formation (C1d)and corresponding sub-volcanic bodies which belong to lime-alkali-alkali series a ssociation.Axi gold deposit considered as the representative of the adular-sericite type was controlled by volcano-structures and the main ore bodies were quartzvein type filling in ring-like fault near crater.And it is low-temperature and low-pressure feature by its ore texture and mineral assem bladge.Yiermande gold deposit considered as the representative of the silicated rock type was controlled by the sedimentary volcanic rocks of the lower part of Dahalajunshan formation and its ore bodies are layer and layer-like.So by analyzing the metallogeno-geo-chemical characteristics of the ore deposits, the authors discuss the settings, conditions and the characteristics of the gold deposit and set up its ore-forming model with epithermal characteristics.
Axi gold deposit and its peripheral ore deposits Yierm ande, Qiabukanzuota, which formed in Late Paleozoic volcanic rocks in West Tianshan Mountains, are considered as epithermal mineralizing type, and divided furtherly in to adular-sericite type and silicated rock type.The gold deposits are formed in Tulasu-Yelimodun volcanic belt of Yili Late Paleozoic rift.And the country rocks of the gold deposit are continental in termediate-acid volcanic eruptive rock series of Dahalajunshan formation (C1d)and corresponding sub-volcanic bodies which belong to lime-alkali-alkali series a ssociation.Axi gold deposit considered as the representative of the adular-sericite type was controlled by volcano-structures and the main ore bodies were quartzvein type filling in ring-like fault near crater.And it is low-temperature and low-pressure feature by its ore texture and mineral assem bladge.Yiermande gold deposit considered as the representative of the silicated rock type was controlled by the sedimentary volcanic rocks of the lower part of Dahalajunshan formation and its ore bodies are layer and layer-like.So by analyzing the metallogeno-geo-chemical characteristics of the ore deposits, the authors discuss the settings, conditions and the characteristics of the gold deposit and set up its ore-forming model with epithermal characteristics.
2003, 36(2): 60-65.
Abstract：
Bailanggou mineralized region is located in the Ordovician back-arc basin volcanic rock belt along the west sectoin of North Qilian Mountains.The pelovolcanic edifice is storaged effectely.The volcanic rock belongs to the upper part of the opholite suite, the volcanic lithofacies developed entirely and the exhalite related copper mineralitation-red jasper is developed abroadly.The copper mineralitation is found in the pelovolcanic edifice every where.They are divided into two kinds, one is related with tectonic crushing belt, the other is the volicanic massive sulfide metallization related with submarine hydrothermal-solution spouting.It shows that there is quite large potential capacity of prospecting rich-copper volicanic massive sulfide deposits in the region.
Bailanggou mineralized region is located in the Ordovician back-arc basin volcanic rock belt along the west sectoin of North Qilian Mountains.The pelovolcanic edifice is storaged effectely.The volcanic rock belongs to the upper part of the opholite suite, the volcanic lithofacies developed entirely and the exhalite related copper mineralitation-red jasper is developed abroadly.The copper mineralitation is found in the pelovolcanic edifice every where.They are divided into two kinds, one is related with tectonic crushing belt, the other is the volicanic massive sulfide metallization related with submarine hydrothermal-solution spouting.It shows that there is quite large potential capacity of prospecting rich-copper volicanic massive sulfide deposits in the region.
2003, 36(2): 66-71.
Abstract：
Chahansala Sb deposit is located in the centre section of southwestern Tianshan which belongs to the western part of Late Paleozoic trench-arc zone in Xinjiang.And it constitutes the Chahansala Sb-Au deposit zone with the Shawayaer dun Au-Sb-Ag deposit the Kalajiaoguya Sb-Au deposit, and the Gulekedabankati Sb-Au deposit.The mineral district sits on the concentrated centre of the Chahansala Sb abnormal area and controlled by a huge thrusting nappestructure.The ore bodies are in the carbon-bearing fragmental rock of the Aertengkeshi formation, and demonstrate the character of multi-element and multi-stage mineralization.The minerogenic material is from the formation that contains the ore bodies, and the minerogenic hydrotherm is the mixed solution that contains the magmatic water, meteoric water, and metamorphic water.
Chahansala Sb deposit is located in the centre section of southwestern Tianshan which belongs to the western part of Late Paleozoic trench-arc zone in Xinjiang.And it constitutes the Chahansala Sb-Au deposit zone with the Shawayaer dun Au-Sb-Ag deposit the Kalajiaoguya Sb-Au deposit, and the Gulekedabankati Sb-Au deposit.The mineral district sits on the concentrated centre of the Chahansala Sb abnormal area and controlled by a huge thrusting nappestructure.The ore bodies are in the carbon-bearing fragmental rock of the Aertengkeshi formation, and demonstrate the character of multi-element and multi-stage mineralization.The minerogenic material is from the formation that contains the ore bodies, and the minerogenic hydrotherm is the mixed solution that contains the magmatic water, meteoric water, and metamorphic water.
2003, 36(2): 72-76.
Abstract：
Hanshan gold deposit discovered by the means of inspecting heavy concentrate anomaly in 1995, is middle-size structure-altered rock type relating to brittle-tough shear zones in teh North Qilian orogenic belt.The formation of deposit is controlled by both ore-bearing stratum and structures, especially the latter.
Hanshan gold deposit discovered by the means of inspecting heavy concentrate anomaly in 1995, is middle-size structure-altered rock type relating to brittle-tough shear zones in teh North Qilian orogenic belt.The formation of deposit is controlled by both ore-bearing stratum and structures, especially the latter.
2003, 36(2): 77-82.
Abstract：
By studying the history of prospecting and ore rehunting in Baiyin orefield and analysing the ore-searchth inking at different periods, some successful experiences and failing lessons during the ore-hunting practice are sumed up.Thus is not only enriched the geology and ore-hunting theory, but also layed a foundation for ore rehunting at present conditions.Especially, under the guidance of academic thought "Subm arine volcanic apparatus-hot brine circulation dynamics" in recent years, new Cu-riched ore bodies have been discovered in the deep of the west segment of Xiaotieshan deposit, and in the deep of Zheyaoshan deposit, indicating that there is broad ore-hunting prospect in the deep of economic deposit existed and its surroundings.The basis for ore rehunting is provided by renewal the ore hunting thinking.
By studying the history of prospecting and ore rehunting in Baiyin orefield and analysing the ore-searchth inking at different periods, some successful experiences and failing lessons during the ore-hunting practice are sumed up.Thus is not only enriched the geology and ore-hunting theory, but also layed a foundation for ore rehunting at present conditions.Especially, under the guidance of academic thought "Subm arine volcanic apparatus-hot brine circulation dynamics" in recent years, new Cu-riched ore bodies have been discovered in the deep of the west segment of Xiaotieshan deposit, and in the deep of Zheyaoshan deposit, indicating that there is broad ore-hunting prospect in the deep of economic deposit existed and its surroundings.The basis for ore rehunting is provided by renewal the ore hunting thinking.
2003, 36(2): 83-86.
Abstract：
Shijuli copper deposits are typical Cyprus-type ones in the western part of North Qilian Mountains.On the basis of the silicon-lead-sulfur isotope constitution of the ores and wall rocks in Shijuli ore area, the author thinks that it is volcanic genesis.The δ30Si(-0.9‰～-0.2‰) from jaspilite and quartz of ores show that they are consistent with ones of basaltic rocks.Lead isotope compositions of pyrites and chlcopy rites are similar to those of basalts in the area.Thus, it is considered that the lead from ores comes mainly from altered basalts.However, sulfur in the deposits may be the results of reactions to different degrees between sea-water and basaltic rocks, because δ34S in pyrites and chlcopyrites varies between 1.5‰～8.88‰
Shijuli copper deposits are typical Cyprus-type ones in the western part of North Qilian Mountains.On the basis of the silicon-lead-sulfur isotope constitution of the ores and wall rocks in Shijuli ore area, the author thinks that it is volcanic genesis.The δ30Si(-0.9‰～-0.2‰) from jaspilite and quartz of ores show that they are consistent with ones of basaltic rocks.Lead isotope compositions of pyrites and chlcopy rites are similar to those of basalts in the area.Thus, it is considered that the lead from ores comes mainly from altered basalts.However, sulfur in the deposits may be the results of reactions to different degrees between sea-water and basaltic rocks, because δ34S in pyrites and chlcopyrites varies between 1.5‰～8.88‰
2003, 36(2): 87-92.
Abstract：
Qicun geothermal field has been developed for more than 30 years.Water temperature drops quickly since large exploitation beganning in 1988.Conceptual model of Qicun geothermal field has been constructed and LUMPFIT is used to predict waterl evel drawdown under different production rates based on multiple well pumping test data as well as temperature prediction.Based on those predictions, reasonable development plan has been put forward, which is critical to future development of Qicun geothermal field.
Qicun geothermal field has been developed for more than 30 years.Water temperature drops quickly since large exploitation beganning in 1988.Conceptual model of Qicun geothermal field has been constructed and LUMPFIT is used to predict waterl evel drawdown under different production rates based on multiple well pumping test data as well as temperature prediction.Based on those predictions, reasonable development plan has been put forward, which is critical to future development of Qicun geothermal field.
Abstract：
Baimiao gas field is half of rollover anticline controlled by Lanliao fault and it is a combination trap not only controlled by structure, but also by lithology.The Baimiao gas field is found in 1980.And the main formations are down of the Sha-2, upside of the Sha-3, middle of the Sha-3 and down of the Sha-3.During the past twenty years, we have mastered the structure characteristics by exploring and researching.And seeking the lithological traps would be geological studying drection, instead of seeking structural trap with going deep into rolling development.The ex ploration indicates that the upside of the Sha-3 is the main producing formation.The relation between sedimentary environment and the distribution of sandst one and the characteristics of lay-aside are discussed emphatically in this paper by researching sediment ary environment of upside of the Sha-3 in Baimiao gas field.It gives the advantageous facies tract of oil and gas gathering.It is very meaning for the next exploration.
Baimiao gas field is half of rollover anticline controlled by Lanliao fault and it is a combination trap not only controlled by structure, but also by lithology.The Baimiao gas field is found in 1980.And the main formations are down of the Sha-2, upside of the Sha-3, middle of the Sha-3 and down of the Sha-3.During the past twenty years, we have mastered the structure characteristics by exploring and researching.And seeking the lithological traps would be geological studying drection, instead of seeking structural trap with going deep into rolling development.The ex ploration indicates that the upside of the Sha-3 is the main producing formation.The relation between sedimentary environment and the distribution of sandst one and the characteristics of lay-aside are discussed emphatically in this paper by researching sediment ary environment of upside of the Sha-3 in Baimiao gas field.It gives the advantageous facies tract of oil and gas gathering.It is very meaning for the next exploration.
Abstract：
In order to ensure the quality of the second grade highway from Xi'an to Ankang and find out the influence of slide in Zhujiawan region on the highway engineering, the geological and seismic geophysical exploration methods were used to explore earth surface and deep geological condition in this slide region.And on the basis of the two methods, the geological situation, origin of the slides and slope stability are mainly focused on studying and analysis in the region.In addition, some satisfactory conclusions are finally drawn by analysis data and information, which are surveyed and collected on the spot.Some conclusion and suggestion will play an important role in the engineering practice in the future.
In order to ensure the quality of the second grade highway from Xi'an to Ankang and find out the influence of slide in Zhujiawan region on the highway engineering, the geological and seismic geophysical exploration methods were used to explore earth surface and deep geological condition in this slide region.And on the basis of the two methods, the geological situation, origin of the slides and slope stability are mainly focused on studying and analysis in the region.In addition, some satisfactory conclusions are finally drawn by analysis data and information, which are surveyed and collected on the spot.Some conclusion and suggestion will play an important role in the engineering practice in the future.
2003, 36(2): 103-108.
Abstract：
Whether the earthquake hazard can be predicted or not, and how are we to achieve efficacious prediction.In this paper, The author thinks that earthquake is a objective reality of nature world and the developing process of seismology, occurrence has inevitably a regularity.If its regularity is recognized and mastered, the prediction would be achieved.Strengthening research on seismic source is the basis to achieve earthquake hazard prediction.Correspondence between yardstick of prediction term and prediction method is good way to improve prediction effect.
Whether the earthquake hazard can be predicted or not, and how are we to achieve efficacious prediction.In this paper, The author thinks that earthquake is a objective reality of nature world and the developing process of seismology, occurrence has inevitably a regularity.If its regularity is recognized and mastered, the prediction would be achieved.Strengthening research on seismic source is the basis to achieve earthquake hazard prediction.Correspondence between yardstick of prediction term and prediction method is good way to improve prediction effect.
2003, 36(2): 109-111.
Abstract：
Based on some drawing water project's engineering condition, the author analyzes and studies it and adopt to dry jet mixing pile method in foundation reinforcement.According to the pile's quality checking, the plan's feasibility is proved.
Based on some drawing water project's engineering condition, the author analyzes and studies it and adopt to dry jet mixing pile method in foundation reinforcement.According to the pile's quality checking, the plan's feasibility is proved.
