共查询到20条相似文献，搜索用时 140 毫秒
1.
邯郸永年洪山碱性岩体及其周边成矿条件优越,已发现金、铜矿化点多处。研究显示金、铜矿床（点）在形成及分布上与洪山岩体有着密切的成因联系。金矿化主要分布在岩体北侧的火山凝灰岩中;铜矿化分布较广,但矿化以岩体中心区域为主。由于岩体剥蚀深度研究程度较低,位于岩体顶部或上方的铜金矿化主体部分是否已遭受风化剥蚀,区内铜金矿化深部找矿潜力如何等问题均亟需分析确定。据此,本文依据岩体“盖层”厚度恢复法、相对隆升剥蚀程度识别法、夷平面法和磷灰石裂变径迹法等综合判别洪山岩体剥蚀深度。不同剥蚀程度判别方法所得结论基本吻合,得出洪山岩体中心区域隆升剥蚀程度最大,在2km左右;岩体南北两侧剥蚀程度逐渐减小。在岩体剥蚀深度分析基础上,给出了区内铜金矿床找矿方向,认为金矿化有利找矿区域在岩体南侧火山凝灰岩分布区,岩体中心部位铜矿化找矿前景不容乐观。 相似文献
2.
秦岭造山带广泛分布的晚三叠世花岗岩是华南板块和华北板块碰撞形成的典型产物，是造山带转入区域伸展构造体制的标志。目前关于秦岭造山带的研究主要集中在地球化学和年代学方面，而有关花岗岩侵位的温压等物理化学条件研究则相对较少。本文通过角闪石全铝压力计和角闪石-斜长石温度计计算，获得其温压数据。结果显示，糜署岭、老君山、秦岭梁、东江口岩体的侵位深度分别为11.4、7.3、8.3、8.5 km,对应于地壳中上部。糜署岭岩体主要为花岗闪长岩，侵位深度大于其余岩体(二长花岗岩),而且岩体的侵位深度主要和岩性有关。利用侵位深度和已发表的热年代学数据，对这些岩体侵位后的剥蚀速率进行估算，结果表明T3-J2的平均剥蚀速率约为140 m/Ma,说明燕山运动和印亚碰撞对秦岭造山带花岗岩的剥蚀贡献不大。 相似文献
3.
西南三江义敦岛弧南端地壳抬升历史及资源评价意义 总被引：5，自引：0，他引：5
云南格咱岛弧成矿带是西南"三江"(怒江、澜沧江、金沙江)多岛弧盆系中一个重要的地质构造单元,位于甘孜—理塘结合带西侧德格—中甸陆块的东缘,印支期义敦岛弧带南端。它始于晚三叠世甘孜—理塘洋壳的向西俯冲,燕山期经历了陆内汇聚和造山后伸展作用阶段,喜山期受青藏高原碰撞隆起效应的影响,本区表现为强烈的逆冲-推覆构造和大规模走滑平移活动。区内岩浆活动强烈,成矿地质条件优越,是近年来新发现的重要铜多金属成矿带,其中以印支期产出于普朗复式岩体的斑岩型铜矿床最为典型。本文通过格咱岛弧岩浆岩带主要成矿斑岩体的磷灰石裂变径迹热年代学的研究表明,裂变径迹年龄分布于12~68Ma,均小于成岩成矿时代,区内主要成矿斑岩体的剥蚀速率为0.046~0.236mm/a,剥蚀程度约为1473~2904m。通过岩体的剥蚀程度与铜多金属矿床的形成深度来分析,各成矿岩体的剥蚀深度基本上小于侵位深度,这对矿床形成后的保存情况较为有利。根据区内主要斑岩型矿床剥蚀资源量的定量计算,将矿床剥蚀情况划分为3个数量级:I级为矿床轻度剥蚀、Ⅱ级为矿床中等剥蚀、Ⅲ级为矿床严重剥蚀,为该区斑岩成矿系统资源潜力评价和深部找矿提供了理论依据。 相似文献
4.
华北克拉通破坏及其成矿事件已引起地学界的广泛关注,其中张宣地区是华北克拉通的重要金矿集中区之一,通过对张宣地区大白阳金矿成矿类型、成矿深度及剥蚀保存的探讨,为区内深部找矿提供了重要的参考依据。文章通过流体包裹体研究对大白阳金矿成矿温度及成矿深度进行计算,利用矿物压力计对矿区周边岩体侵位深度进行估算。流体包裹体研究结果显示大白阳金矿成矿温度160~220℃、盐度w（NaCleq）=9%~15%,密度0.78~0.97 g/cm3、压力46.3~104.6 MPa,成矿流体主要属于NaCl-H2O体系,成矿过程中流体温度和盐度都呈现明显的降低趋势。采用黑云母压力计,针对大白阳金矿周边谷嘴子、杨家营以及前坝口花岗质岩体的侵位深度进行估算,并对大白阳金矿自形成以来的剥蚀保存情况进行了探讨,估算结果显示,谷嘴子岩体（236.0 Ma）成岩深度7.02 km、杨家营岩体（138.6 Ma）成岩深度2.66 km、前坝口岩体（140.2 Ma）成岩深度3.13 km。结合前人的裂变径迹结果,认为张宣地区自中生代以来剥蚀速率为0.022~0.029 km/Ma,剥蚀量为3 km。按照前述成矿压力46.3~104.6 MPa换算,大白阳金矿成矿深度6.93 km,剥蚀量小于矿床成矿深度,说明该矿深部仍具有良好的找矿前景。 相似文献
5.
6.
成矿后含矿地质体的剥露程度与矿体的保存关系是矿床学研究的疑难问题之一.利用中酸性侵入岩体的出露程度, 结合磷灰石裂变径迹测试结果及现今发现的矿产展布特征, 探讨天山山脉剥露程度与内生金属矿产保存之间的关系, 进而为区域找矿提供理论指导.统计结果表明, 北天山西段的依连哈比尕尔山、中段的博格达山和西南天山山脉皆缺乏大面积分布的深成侵入岩, 已经发现的内生金属矿产较少, 且以中低温的矿床为主; 北天山南部的觉罗塔格地区、中天山和南天山东段都大面积出露中酸性岩体, 已经发现了大量大型-超大型规模内生金属矿床, 以中高温成矿为特征; 综合分析已有的磷灰石裂变径迹测年结果统计显示, 北天山西段的依连哈比尕山、中段的博格达山和西南天山中生代晚期开始隆升, 新生代25 Ma以来隆升强烈; 北天山南部、中天山以及南天山东段山脉从侏罗纪早期就已经开始隆升而接受剥蚀, 新生代隆升较弱.结合现今山脉的地质背景、内生金属矿产展布特征、山脉隆升时间及其现今地貌特征推测, 北天山西段的依连哈比尕山、中段的博格达山和西南天山山脉由于剥蚀时间短, 因而其剥蚀程度相对较低, 地表仍出露表壳的沉积-火山岩系, 以中酸性侵入岩体为代表的深成岩体由于剥蚀量不够而还没有出露于地表, 地表出露低温的内生金属矿产; 北天山南部、中天山以及南天山东段山脉开始隆升时间早, 新生代隆升弱, 因而总体上剥蚀量、剥蚀程度大, 表壳岩系已经剥蚀殆尽, 广泛出露深成侵入岩体, 与中酸性岩体侵位有关的中高温矿产广泛展布.为此, 进一步指出了在天山山脉不同构造分区内应该着重寻找不同类型、不同成矿温度的内生金属矿产, 推测西南天山具有较好的找矿远景空间, 并认为山体剥露程度的差异是造成所谓"大矿不过国界"的主要原因之一. 相似文献
7.
华北克拉通于中生代遭受严重破坏的观点已被地学界广泛接受。其北缘的辽西地区赤峰—朝阳金成矿带之岩浆作用和成矿作用被认为是克拉通破坏事件的典型响应。在区域地质和矿床地质调查的基础上,选择该矿带的金厂沟梁金矿区和排山楼金矿区,分别针对与成矿时间一致的西对面沟岩体(成岩时间128 Ma)和大石头沟岩体(成岩时间128~126 Ma)进行了矿物组合、结晶温度、氧逸度和侵位深度研究。采用黑云母全铝压力计获得两个岩体结晶压力平均值分别为97 MPa和145 MPa,按照地壳密度2.7 g/cm3估算了两个岩体的侵位深度分别为3.67 km和5.48 km。根据以上估算结果并结合前人研究成果,认为早白垩世以来赤峰—朝阳金成矿带剥蚀深度应该在3.67~7.70 km范围,平均值5.27 km。此外,在收集和综合对比分析华北地区隆升剥蚀资料的基础上,认为自早白垩世以来华北地区总体剥蚀深度范围为2.0~10.0 km,主要集中在2.0~6.0 km,平均值约5.60 km。这一认识对于华北地区进一步找矿具有重要参考意义。 相似文献
8.
《现代地质》2015,(3)
北京房山岩体是华北克拉通东部典型的燕山期中酸性钙碱性侵入岩之一。为了更好地理解房山岩体的侵位机制和隆升-剥蚀历史,选取恰当的角闪石全铝压力计和角闪石-斜长石温度计计算其侵位压力和温度。结果表明,房山岩体的结晶压力为((0.39~0.28)±0.06)GPa,温度为655.9~733.7℃。基于该结果,认为房山岩体在侵位过程中经历了变压结晶作用。结合房山岩体各岩石单元的侵位温度、压力、岩石结构特征以及锆石U-Pb年龄,可知其在早期经历了缓慢的隆升剥蚀过程,而晚期的巨斑状中细粒花岗闪长岩单元遭受了快速的隆升剥蚀。根据本研究估算的侵位温度和压力,房山岩体在持续侵位过程中抬升了7~8 km,平均抬升速率为2.33~2.67 km/Ma。 相似文献
9.
《西北地质》2016,(1)
在野外地质调查和岩相学研究基础上,运用电子探针技术对青海香日德水文站岩体中不同类型的斜长石及其环带进行研究,探讨了香日德水文站岩体中斜长石环带的成因,反演岩浆演化过程,计算了地表剥蚀和隆升速率。结果表明,香日德水文站岩体中斜长石具有正环带和韵律环带;石英闪长岩和包体中矿物结晶深度约12km;花岗闪长岩中矿物结晶深度约9km;由侵位深度计算的地表剥蚀速率为0.04km/Ma,20Ma以来隆升速率为0.6km/Ma,3.6 Ma以来隆升速率为3.0km/Ma。此外,研究得出斜长石环带由Ca2+!Na+,Al 3+!Si 4+的强交代作用和Fe3+!Si 4+的弱交代作用支配,认为香日德水文站岩体的演化不是简单的侵位模式,而是岩浆交替侵位、多次混合的过程。 相似文献
10.
新疆香山杂岩体的成岩与成矿时序 总被引：6，自引：2，他引：4
新疆东天山香山地区镁铁-超镁铁杂岩体中产有香山中中型铜镍矿和香山西大型铜镍-钛铁矿床.杂岩体可分为辉长岩类、超镁铁质岩类和钛铁辉长岩类.野外证据表明三者具有先后侵位关系.本文通过对香山杂岩体不同岩相年代学资料梳理,补充了定年数据,获得香山杂岩体侵位年龄为283.2±2.1Ma,验证了不同岩石系列的侵位时序.此外,锆石年龄数据还记录了本地区曾经发生过的构造-岩浆热事件.利用角闪石40Ar/39Ar测年结果,并结合锆石U-Pb测年结果推测香山西岩体侵位较深,香山中岩体侵位较浅,进一步推测西岩体剥蚀量较大,而中岩体剥蚀量较小.结合野外穿插关系,厘定了杂岩体侵入-成矿事件的时序. 相似文献
11.
Emily Keeble David I. Whiteside Michael J. Benton 《Proceedings of the Geologists' Association. Geologists' Association》2018,129(2):99-119
Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco. 相似文献
12.
Gilles Serge Odin 《Comptes Rendus Geoscience》2002,334(6):409-414
Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414. 相似文献
13.
The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts 总被引：4，自引：0，他引：4
The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H2O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H2O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species. 相似文献
14.
Emmanuel Skourtsos Daniel Vachard Alexandra Zambetakis-Lekkas Rossana Martini Louisette Zaninetti 《Comptes Rendus Geoscience》2002,334(12):925-931
Some olistolites reworked in a Tertiary flysch of Mount Parnon (Peloponnesus, Greece) exhibit a Late Permian assemblage, dominated by Paradunbarula (Shindella) shindensis, Hemigordiopsis cf. luquensis and Colaniella aff. minima. This association corresponds to the Late Wuchiapingian (=Late Dzhulfian), a substage whose algae and foraminifera are generally little known. Contemporaneous limestones crop out in the middle part of the Episkopi Formation in Hydra, but they are rather commonly reworked in Mesozoic and Cainozoic sequences. The palaeobiogeographical affinities shared by the foraminiferal markers of Greece, southeastern Pamir, and southern China, are very strong (up to the specific level), and are congruent with the Pangea B reconstructions. To cite this article: E. Skourtsos et al., C. R. Geoscience 334 (2002) 925–931. 相似文献
15.
正20141596 Liu Yunhuan(School of Earth Sciences and Resources,Chang’an University,Xi’an 710054,China);Shao Tiequan Early Cambrian Quadrapyrgites Fossils of Xixiang Boita in Southern Shaanxi Province(Journal of Earth Sciences and Environment,ISSN1672-6561,CN61-1423/P,35(3),2013,p.39-43,3 illus.,20 refs.) 相似文献
16.
正20141719 Chen Zhijun(State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,China);Chen Jianguo Automated Batch Mapping Solution for Serial Maps:A Case Study of Exploration Geochemistry Maps(Journal of Geology,ISSN1674-3636,CN32-1796/P,37(3),2013,p.456-464,2 illus.,2 tables,10 refs.) 相似文献
17.
正20140962 Chen Fenning(Xi’an Institute of Geology and Mineral Resources,Xi’an710054,China);Chen Ruiming Late Miocene-Early Pleistocene Ostracoda Fauna of Gyirong Basin,Southern Tibet(Acta Geologica Sinica,ISSN0001-5717,CN11-1951/P,87(6),2013,p.872-886,6illus.,56refs.) 相似文献
18.
正1.IGNEOUS PETROLOGY20142008Cai Jinhui(Wuhan Center,China Geological Survey,Wuhan 430205,China);Liu Wei Zircon U-Pb Geochronology and Mineralization Significance of Granodiorites from Fuzichong Pb-Zn Deposit,Guangxi,South China(Geology and Mineral Resources of South China,ISSN1007-3701,CN42-1417/P,29(4),2013,p.271-281,7illus., 相似文献
19.
正20141205Cheng Weiming(State Key Laboratory of Resources and Environmental Information System,Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China);Xia Yao Regional Hazard Assessment of Disaster Environment for Debris Flows:Taking Jundu Mountain,Beijing as an 相似文献
20.
正20141266Fan Chaoyan(Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes,Guangzhou 510275,China);Wang Zhenghai On Error Analysis and Correction Method of Measured Strata Section with Wire Projection Method(Journal of 相似文献