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1.
《地球化学》1973,(3):165-172
26 determinations of the isotopic ages of granites and pegraatites by the K-Ar method are reported for the eastern section of the Eastern Tsinling. There may exist three periods of granites in this region, i.e., (1) late period of Early Paleozoie (420--450m.y.), (2) early period of Late Paleozoie (370-380m.y.)and (3) Mesozoic (178 m.y.) The granitic pegraatites are concentrated, in two regions-the eastern and the western regions. The western re,on is dated to be 400 m.y. Or more, and the eastern region, 370--380 m.y. Two samples of metamorphic rock from Ching-you-ho of Shangnan, Shensi and Lung-ehuan-ping of Lushi, Honan, are determined to be 451 and 453 m.y. respectively. 相似文献
2.
Fluid inclusions are commonly observed in various stages during the diage-netic evolution and the generation,migration and accumulation of hydrocarbons in Lower Permian carbonate rocks in the Xichang Basin, providing direct physico-chemical evidence for the process.Altogether seven stages can be recognized,ie.,the penecontemporane-ous, early and mid-late diagenetic stages, the epidiagenetic stage and the early, middle and late reburying stages.Karst and dissolution pores and structural fissures developed during the epidiagenetic and reburying stages constitute the major reservoirs for hydro-carbon accumulation.Oil generation and migration began in the early reburying stage in Late Permian time and developed to its climax in the middle reburying stage in the Triassic period, followed by extensive generation and migration of natural gases during the late stage of reburying in the Jurassic and later periods.The generation,migration and accumulation of hydrocarbons are closely related to Hercynian basalt eruption and Indosinian and Yenshanian tecto-magmatism. 相似文献
3.
The available data on K-Ar dating of Yenshanian granites in Zhejiang Province have been summarized in the present paper. Based on K-Ar isochron ages of the granites, in conjunction with geological evidence, three episodes of granitic magmatic intrusion are distinguished as follows: the first episode--160--135 m.y., the second-130-110 m.y. and the third--105--65 m.y. Furthermore, the tempo-spacial distribution of K-Ar ages and their geotectonic implieations are also discussed. 相似文献
4.
大厂花岗岩年龄及成矿时代 总被引：1，自引：0，他引：1
The Dachang tin ore fields is one of the largest in China, where eassiterite-sulphide-type ore deposits occur. The ages of Dachang granites which are closely related to the ore deposits are discussed in this paper. Based on sixteen K-At biotite and one U-Pb zircon ages, it is suggested that Dachang granites were formed at 72--102 m.y.The cooling rates of Dachang granites have been estimated at 18.4℃/m.y. in the arly, 13.3℃/m.y. in the middle, and 4.5℃/m.y. in the late period. 相似文献
5.
西藏高原南部花岗岩类同位素地质年代学 总被引：19，自引：0，他引：19
In the study of isotopic geochronology of grauitoids in the southern part of Xizang plateau, 103 mica and zircon ages were determined by K-At method and U-Pb method. Based upon the above mica and zircon ages of various types of granitoid, together with their geological setting, three intrusive stages have been distinquished for granitoids in Southern Xizang : the first stage, 120--70 m. y. (late Yenshanian) ; the second stage,50---30 m.y. (early Himalayan) ; the third stage, 20--10 m.y. (late Himalayan). It is evident from the characteristic zonal distribution patterns of granitoids and the spacial-temporal consistency in their isotopic geochronology that there exists a close inter-connection between the subduetion stage and the collision stage. 相似文献
6.
庐枞地区安粗岩系 总被引：26，自引：2，他引：26
Volcanic rocks discussed here are distributed in the Lujizng-Zongyang region, Anhui province, covering an area of about 100 km^2, where a set of potash-rich intermediate series is developed which is particularly referred to as “Latitic Series”. The characters of the latitic series are as follows: (1) It was formed during middle Yenshanian (108--132 m.y.) ; (2) Spatially, it occurs frequently on the continental side of closing slab boundary stretching along the deep rift zone; (3) It is mainly composed of latite, trashybasalt and trachyte; (4) It contains sanidine coexisting with augite, plagioclase (labradonite, andesine and oligoclase) and magnetite, and clinopyroxene, formed under high pressure conditions, as well as pseudoleucite with no orthopyroxene and quartz; (5) The chemical composition is characterized by high alkalis, especially potasinm,with the ratio of K2O/Na2O≥1 and high alnminium but low titanium. The formation of latitis magma could be related with the slab movement. It has been shown that volcanic activities during middle Yenshanian were rather weak in intensity and small in scale as compared with those during late Yenshanian. The rather slow movement of Pacific slab during middle Yenshanian could not provide sufficient water and rubbing heat energy to the slab boundary, and therefore, partial melting could proceed only at the upper mantle depth (100-200km). It is believed that the partial melting of phlogopitelberzolite in some local regions of the continental mantle along the dosing slab boundary was responsible for the formation of potash- and aluminium-rich latitic magma, 相似文献
7.
西藏南部花岗岩类稀土元素地球化学 总被引：1，自引：0，他引：1
REE abundances of granitoids in Southern Xizang were estimated to be within the range of 190 ppm (REE oxides), which are much lower than the average REE abundance of intermediate-acidic intrusive rocks in the crust. The REE abundances show a progressive decrease from late Yenshanian to late Himalayan (195--128 ppm). Four types of REE distribution patterns have been distinguished: (1) rightly deelined smooth curves, showing little Eu anomaly (δEu-values are 0.78-0.95) and relative enrichment of heavy REE (Diorite and granodiorite, fore example, are characterized by such a pattern) ; (2) rightly declined V-shape curves, displaying negative Eu anomaly(δEu: 0.50--0.70) (Biotite-granite shows sneh a pattern.) ; (3) righly declined V-shape curves with noticeable Eu anomaly (δEu : 0.36--0.39) (Two-mica granite and tourmalinemuscovite granite possess this pattern) ; and (4) rightly declined V-shape eurves with strong Eu anomaly (δEu : 0.27--0.86) (Porphyritie biotite-granite has such a pattern). In summary, the granitoids in this given area could be divided into two types, i. e.,the abyssal type (e. g. diorite, granodiorite) and the hypabyssal type (e.g. two-mica granite and tourmaline muscovite granite). 相似文献
8.
Age division of Nanling granites are discussed in relation to geological,stratigraphical,age and other data,The author believes that in Nanling region there exist granites of Xuefeng,Caledonian,Hercynian,Indosinian and Yenshanian ages.Five intrusive stages can be reeognized within the Yenshanian period.The granite belts of Qitianling-Jiufeng and Dadongshan-Guidong,whose ages have been in lively debate for a long time,can be considered as composite belts consisting of multistage emplacement. 相似文献
9.
Early carbonate cements in the Yanchang Formation sandstones are composed mainly of calcite with relatively heavier carbon isotope （their δ^18O values range from -0.3‰- -0.1‰） and lighter oxygen isotope （their δ^18O values range from -22.1‰- -19.5‰）. Generally, they are closely related to the direct precipitation of oversaturated calcium carbonate from alkaline lake water. This kind of cementation plays an important role in enhancing the anti-compaction ability of sandstones, preserving intragranular volume and providing the mass basis for later disso- lution caused by acidic fluid flow to produce secondary porosity. Ferriferous calcites are characterized by relatively light carbon isotope with δ^13C values ranging from -8.02‰ to -3.23‰, and lighter oxygen isotope with δ^18O values ranging from -22.9‰ to -19.7‰, which is obviously related to the decarboxylation of organic matter during the late period of early diagenesis to the early period of late diagenesis. As the mid-late diagenetic products, ferriferous cal- cites in the study area are considered as the characteristic authigenic minerals for indicating large-scaled hydrocarbon influx and migration within the clastic reservoir. The late ankerite is relatively heavy in carbon isotope with δ^13C values ranging from -1.92‰ to -0.84‰, and shows a wide range of variations in oxygen isotopic composition, with δ^18O values ranging from -20.5‰ to -12.6‰. They are believed to have nothing to do with decarboxylation, but the previously formed marine carbonate rock fragments may serve as the chief carbon source for their precipitation, and the alkaline diagenetic environment at the mid-late stage would promote this process. 相似文献
10.
Fluid inclusions in minerals filled in pores of reservoir rocks can be used as a good indicator of pore genesis and development so as to shed light on oil generation,migration and accumulation.The relationship between pore evolution and oil generation has been established based on fluid inclusion studies on the Lower Ordovician carbonate reservoir strata in the Ordos Baisn,Northwest China.Seven stages of porosity development can be recogmized.i.e.,the penecontemporaneous,the early and middle-late diagenetic,the supergene,the early,middle and late re-burying stages.The dissolution pores an fissures formed in the supergene and middle-late reburying stage and the structural fractures formed in the late re-burying stage constitute the major traps of oil and gas.The major phase of oil migration and accumulation took place between Late Jurassic and Cretaceous,Corresponding to the middle and late re-burying stages.The generation and accumulation of oil can be closely related to Yenshanian tectonics. 相似文献
11.
WEN Quanbo LIU Yongjiang LIANG Chenyue Li Weimin SHAO Yilun ZHANG Qian ZHANG Duo LIU Xinyue 《《地质学报》英文版》2019,93(5):1580-1590
The NE–striking Jiamusi–Yitong fault zone(JYFZ) is the most important branch in the northern segment of the Tancheng–Lujiang fault zone. The precise shearing time of its large–scale sinistral strike–slip has yet to determined and must be constrained. Detailed field investigations and comprehensive analyses show that strike–slip faults or ductile shear belts exist as origination structures along the western region of Yitong Graben. The strike of the shear belts trend to the NE–SW with steep mylonitic foliation. The zircon U–Pb dating result for the granite was 264.1±1 Ma in the ductile shear belt of the JYFZ. The microstructural observation(rotated feldspar porphyroclasts, S–C fabrics, and quartz c–axis fabrics, etc.) demonstrated the sinistral shearing of the ductile shear zones. Moreover, the recrystallized quartz types show a transitional stage of the subgrain rotation toward the recrystallization of the grain boundary migration(SR–GBM). Therefore, we suggest that the metamorphic grade of the shear zone in the ductile shear zones should have reached high greenschist facies conditions, and the deformation temperatures should approximately 450–500°C, which is obviously higher than the blocking temperature of muscovite(300–400°C). Hence, the ~(40)Ar/~(39)Ar isochron age of muscovite from ductile shear zones should be a cooling age(162.7±1 Ma). We infer that the sinistral strike–slipping event at the JYFZ occurred in the late Jurassic period, and it was further inferred from the ages of the main geological events in this region that the second sinistral strike–slip age of the Tancheng–Lujiang fault zone occurred during the period of tectonic movements in the Circum–Pacific tectonic domain. This discovery also indicates the age of the Tancheng–Lujiang fault zone that stretches to northeastern China. The initiation of the JYFZ in the late Jurassic is related to the speed and direction of oblique subduction of the west Pacific Plate under the Eurasian continent and is responsible for collision during the Jurassic period. 相似文献
12.
西藏南部中酸性岩中锆石铀-铅计时讨论 总被引：2，自引：0，他引：2
U-Pb isotopie geological ages were determined on more than 30 specimens of zircon,feldspar, sphene and apatite from the Kangdeee rock belt and its eastern Bome-Zayu areas in Xizang (Tibet). The study of common lead derivation and its mode of occurrence in zircon indicates that large amounts of common lead occur as sulphide-faeies minerals er exist in the cyrstal lattice of zircon, rather than introduced by contamination during analytical procedure. Described in this paper is the validity of subtracting zircon-containing common lead from the isotopie components of syngenetic galena, consequently leading te the conelusion that intermediate-acid rocks in the studied region are brought forth by late Yenshanian (120--80 m. y.) movement, It is suggested from the quantity of common lead and the difference in lead isotopic composition that the western segment of the Kangdese belt and its eastern Beme-Zayu areas may have two different material sources. 相似文献
13.
The Shazi anatase ore deposit in Qinglong, Guizhou Province, is a large-sized anatase deposit that has been recently explored. The characteristics of major oxides in the ore are similar to those of modem laterite weath- ering crust and laterite in the laterite-type gold deposits in the western part of Guizhou Province. Studies on the REE characteristics of basalts and anatase ores in the study region showed that both of them do have extremely strong affinities. There are two groups of trace elements in the ores, i.e., Au-Ag-As-Sb-Hg-Tl association and Sc-TiO2-Cu-Fe-Mn association, reflecting that the formation of anatase ore is related to the formation of siliceous claystone at the early stage of eruption of the Emeishan basaltic magma. The siliceous claystones are the major country rocks for the formation of laterite-type gold ores and anatase ores. In the region anatase ores are rich in Sc and the basalts enriched in Fe, Mn, Ti and Sc are the material source of metallogenesis. 相似文献
14.
Franco PIRAJNO 《《地质学报》英文版》2007,81(2)
Based on the new data of isotopic ages and geochemical analyses, three types of Mesozoic granites have been identified for the Xiong'ershan-Waifangshan region in western Henan Province: high-Ba-SrⅠ-type granite emplaced in the early stage (～160 Ma),Ⅰ-type granite in the middle stage (～130 Ma) and anorogenic A-type granite in the late stage (～115 Ma). Geochemical characteristics of the high-Ba-SrⅠ-type granite suggest that it may have been generated from the thickened lower crust by partial melting with primary residues of amphibole and garnet. Gradual increase of negative Eu anomaly and Sr content variations reflect progressive shallowing of the source regions of these granites from the early to late stage. New 40Ar/39Ar plateau ages of the early-stage Wuzhangshan granite (156.0±1.1 Ma, amphibole) and middle-stage Heyu granite (131.8±0.7 Ma, biotite) are indistinguishable from their SHRIMP U-Pb ages previous published, indicating a rapid uplift and erosion in this region. The representative anorogenic A-type granite, Taishanmiao pluton, was emplaced at～115 Ma. The evolution of the granites in this region reveals a tectonic regime change from post-collisional to anorogenic between～160 Ma and～115 Ma. The genesis of the early- and middle-stageⅠ-type granites could be linked to delamination of subducted lithosphere of the Qiniing orogenic belt, while the late-stage A-type granites represent the onset of extension and the end of orogenic process. In fact, along the Qiniing -Dabie-Sulu belt, the Mesozoic granitoids in western Henan, Dabieshan and Jiaodong regions are comparable on the basis of these temporal evolutionary stages and their initial 87Sr/86Sr ratios, which may suggest a similar geodynamic process related to the collision between the North China and Yangtze cratons. 相似文献
15.
Characteristics of the Mesozoic and Cenozoic Tectonic Stress Fields of the Urumqi-Usu Region, Xinjiang 总被引：1，自引：0，他引：1
Tao Mingxin Lanzhou Institute of Geology Academia Sinic Beijing Jiang Minxi 《《地质学报》英文版》1993,67(1):17-31
Based on the study of folds and related conjugate shear joints, the tectonic stress fields of the Urumqi-Usu region to the north of the North Tianshan Mountains have been reconstructed. Furthermore the author discussed the tectonic movements and their dynamic features. The early tectonic movement in the investigated region occurred from the end of the Late Jurassic to the initial stage of the Early Cretaceous, with the maximum (tensile) and minimum (compressional) principal stress trajectories in the tectonic stress field being in E-W and S-N directions respectively; the late tectogenesis took place from the end of the Early Pleistocene to the initial Middle Pleistocene, with the maximum and minimum principal stress trajectories in the late stress field striking in WNW and NE-NNE directions respectively. Through computer-aided simulated calculation by the finite element method and analysis of geological structure, it has been ascertained that the early tectogenesis is a nearly N-S compressive movement and the late one a NE to nearly N-S compressive movement with reverse shear. The dynamic force which caused the tectogeneses came from the movement of the southern major fault, i.e. the North Tianshan Mountains. 相似文献
16.
Evolution of the Mesozoic Granites in the Xiong＇ershan-Waifangshan Region, Western Henan Province, China, and Its Tectonic Implications 总被引：4，自引：0，他引：4 
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下载免费PDF全文 Based on the new data of isotopic ages and geochemical analyses, three types of Mesozoic granites have been identified for the Xiong'ershan-Waifangshan region in western Henan Province: high-Ba-Sr I-type granite emplaced in the early stage (～160 Ma), I-type granite in the middle stage (～130 Ma) and anorogenic A-type granite in the late stage (～115 Ma).Geochemical characteristics of the high-Ba-Sr I-type granite suggest that it may have been generated from the thickened lower crust by partial melting with primary residues of amphibole and garnet. Gradual increase of negative Eu anomaly and Sr content variations reflect progressive shallowing of the source regions of these granites from the early to late stage. New 40Ar/39Ar plateau ages of the early-stage Wuzhangshan granite (156.0±1.1 Ma, amphibole) and middle-stage Heyu granite (131.8±0.7 Ma, biotite) are indistinguishable from their SHRIMP U-Pb ages previous published, indicating a rapid uplift and erosion in this region. The representative anorogenic A-type granite, Taishanmiao pluton, was emplaced at ～115 Ma. The evolution of the granites in this region reveals a tectonic regime change from post-collisional to anorogenic between ～160 Ma and ～115 Ma. The genesis of the early- and middle-stage I-type granites could be linked to delamination of subducted lithosphere of the Qinling orogenic belt, while the late-stage A-type granites represent the onset of extension and the end of orogenic process. In fact, along the Qinling -Dabie-Sulu belt, the Mesozoic granitoids in western Henan, Dabieshan and Jiaodong regions are comparable on the basis of these temporal evolutionary stages and their initial 87Sr/86Sr ratios,which may suggest a similar geodynamic process related to the collision between the North China and Yangtze cratons. 相似文献
17.
Fluid Inclusion Studies of the Skarn—type Tin Mineralization at Red—A—ven,Northwest Dartmoor,England
Two principal hydrothermal events have been recognized ,which resulted in the tin-bearing skarns at Red-A-ven ,Northwest Dartmoor.Tin was enriched during both the early (occurring as tin-bearing andradite) and late hydrothermal events (mainly as malayaite stannite and cassiterite,accompanied by boron silicates and minor tungsten).Thermometric measurements of fluid inclusions in diopside,garnet,malayaite,tourmaline-quartz and axinite were carried out,suggesting that the early skarns were formed at the temperature above 600℃and the salinities ranging from 10 to 20 wt.% NaCl eq.while the late skarns at the temperatures of 350-460℃ and the salinities ranging from 30 to 50wt.% NaCl eq.The estimated minimum depths are 2856m(850 bar) for the early event and 2526m(185 bar) for the late event.The birefringence of the andradite might be related with the superimposition of late hydrothermal fluids. 相似文献
18.
Evolution of the Mesozoic Granites in the Xiong''''ershan-Waifangshan Region,Western Henan Province,China,and Its Tectonic Implications 下载免费PDF全文
下载免费PDF全文 Franco PIRAJNO 《《地质学报》英文版》2007,(2)
Based on the new data of isotopic ages and geochemical analyses, three types of Mesozoic granites have been identified for the Xiong'ershan-Waifangshan region in western Henan Province: high-Ba-SrⅠ-type granite emplaced in the early stage (～160 Ma),Ⅰ-type granite in the middle stage (～130 Ma) and anorogenic A-type granite in the late stage (～115 Ma). Geochemical characteristics of the high-Ba-SrⅠ-type granite suggest that it may have been generated from the thickened lower crust by partial melting with primary residues of amphibole and garnet. Gradual increase of negative Eu anomaly and Sr content variations reflect progressive shallowing of the source regions of these granites from the early to late stage. New 40Ar/39Ar plateau ages of the early-stage Wuzhangshan granite (156.0±1.1 Ma, amphibole) and middle-stage Heyu granite (131.8±0.7 Ma, biotite) are indistinguishable from their SHRIMP U-Pb ages previous published, indicating a rapid uplift and erosion in this region. The representative anorogenic A-type granite, Taishanmiao pluton, was emplaced at～115 Ma. The evolution of the granites in this region reveals a tectonic regime change from post-collisional to anorogenic between～160 Ma and～115 Ma. The genesis of the early- and middle-stageⅠ-type granites could be linked to delamination of subducted lithosphere of the Qiniing orogenic belt, while the late-stage A-type granites represent the onset of extension and the end of orogenic process. In fact, along the Qiniing -Dabie-Sulu belt, the Mesozoic granitoids in western Henan, Dabieshan and Jiaodong regions are comparable on the basis of these temporal evolutionary stages and their initial 87Sr/86Sr ratios, which may suggest a similar geodynamic process related to the collision between the North China and Yangtze cratons. 相似文献
19.
Evolution of the Mesozoic Granites in the Xiong''ershan-Waifangshan Region,Western Henan Province,China,and Its Tectonic Implications 下载免费PDF全文
下载免费PDF全文 Franco PIRAJNO 《《地质学报》英文版》2007,81(2)
Based on the new data of isotopic ages and geochemical analyses, three types of Mesozoic granites have been identified for the Xiong'ershan-Waifangshan region in western Henan Province: high-Ba-SrⅠ-type granite emplaced in the early stage (～160 Ma),Ⅰ-type granite in the middle stage (～130 Ma) and anorogenic A-type granite in the late stage (～115 Ma). Geochemical characteristics of the high-Ba-SrⅠ-type granite suggest that it may have been generated from the thickened lower crust by partial melting with primary residues of amphibole and garnet. Gradual increase of negative Eu anomaly and Sr content variations reflect progressive shallowing of the source regions of these granites from the early to late stage. New 40Ar/39Ar plateau ages of the early-stage Wuzhangshan granite (156.0±1.1 Ma, amphibole) and middle-stage Heyu granite (131.8±0.7 Ma, biotite) are indistinguishable from their SHRIMP U-Pb ages previous published, indicating a rapid uplift and erosion in this region. The representative anorogenic A-type granite, Taishanmiao pluton, was emplaced at～115 Ma. The evolution of the granites in this region reveals a tectonic regime change from post-collisional to anorogenic between～160 Ma and～115 Ma. The genesis of the early- and middle-stageⅠ-type granites could be linked to delamination of subducted lithosphere of the Qiniing orogenic belt, while the late-stage A-type granites represent the onset of extension and the end of orogenic process. In fact, along the Qiniing -Dabie-Sulu belt, the Mesozoic granitoids in western Henan, Dabieshan and Jiaodong regions are comparable on the basis of these temporal evolutionary stages and their initial 87Sr/86Sr ratios, which may suggest a similar geodynamic process related to the collision between the North China and Yangtze cratons. 相似文献
20.
Made in the present paper is a further diseussion on the genetic relations between orogenic movements and. the formation of granitic rocks. These two major gcological processes affected one another, thus leading to the formation of the con.tincntal crust and its evolution. It seems undoubted that Hereynian granites are closely related to the Hercynian orogeny, especially in the Qinzhou Region. Based upon the geological evidence and geochronological data, the geological timescale for the granites of different ages is proposed as follows : Donganian granites --approximately from 1450 to 1300m.y.; Hsuehfengian granites--from 1000 to 650m.y. ; early-Caledonian granites--from 570 to 420 m.y. ; late-Caledonian granites from 420 to 340 m.y. ; Hercynian granites-- from 800 to 250 m.y. ; Indosinian granites--from 250 to 185 m.y. ; early-Yenshanian granites-- from 185 to 137 m.y. and late.Yenshanian granites- from 137 to 67 m.y. 相似文献