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The complex evolutionary history of collision-related suture zones in the western Qiangtang is poorly understood, due to the lack of pivotal magmatic and tectonic records. The Chem Co intermediate-felsic batholith is situated in the westernmost section of Qiangtang, where it intruded into the Upper Paleozoic metamorphic sedimentary series and was cut by Late-Cenozoic active normal faults. Here, we present evidence from field observations, geochemistry, zircon UPb and Hf isotopes, and mica 40Ar39Ar analysis of these granitoid rocks. Zircon UPb ages ranging from 107.3 ± 1.4 to 123.7 ± 1.7 Ma reveal that this magmatism initiated in the Early Cretaceous. Mica 40Ar39Ar yield plateau ages from 99 to 118 Ma suggest rapid emplacement into the cold crust without disturbance by subsequent >320 °C tectono-thermal events. Major element geochemistry shows these granitic rocks are enriched in Al, depleted in Ca, lie mostly within the high–K calc–alkaline series and have peraluminous features. Mineral modes that lack amphibole but contain muscovite, together with the geochemical characteristics, indicate an S–type granite affinity. Furthermore, the rocks are strongly enriched in large-ion lithophile elements (LILE) and light rare earth elements (LREE), and are moderately to strongly depleted in high field strength elements (HFSE) and heavy rare earth elements (HREE), thus indicating typical characteristics of arc-related magmatic rocks. Considering the petrogenesis, geochemical features, zircon UPb ages, negative zircon εHf(t) values, similarity with the southwestern Qiangtang intrusions, and the geological setting, we conclude that the Chem Co granite was derived from the anatexis of crustal lithosphere through a “soft” collision associated with the continuing northwards subduction of the Bangong–Nujiang Tethyan (BNT) Ocean. We propose that the final closure and termination of the western segment of the BNT Ocean was completed later than 107 Ma. 相似文献
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LIN Bin TANG Juxing TANG Pan SUN Yan QI Jing M. SANTOSH XIE Jinling DENG Shilin LI Faqiao XIE Fuwei ZHOU Aorigele 《《地质学报》英文版》2024,98(1):83-103
Rubidium (Rb) deposits mostly occur in the South China and Central Asia orogenic belts and are often closely associated with highly differentiated granites. This study investigates a newly-discovered giant Rb deposit at Gariatong in the Central Lhasa terrane in Tibet. Detailed field studies and logging data revealed that the Rb mineralization mainly occurs in monzogranite and is related to greisenization. LA-ICP-MS U-Pb dating of zircon yielded ages of 19.1 ± 0.2 Ma and
19.0 ± 0.2 Ma for greisenized monzogranite and fresh monzogranite, respectively. The monzogranites are characterized as strongly peraluminous, with high contents of SiO2, Al2O3, K2O and Na2O as well as a high differentiation index. They are enriched in light rare earth and large ion lithophile elements with signi?cant negative Eu anomalies and depleted high field-strength elements. Petrological and geochemical features of these ore-related monzogranites suggest that they are highly fractionated S-type granites, derived from remelting of crustal materials in a post-collisional setting. The geochemistry of zircon and apatite points to a low oxygen fugacity of the ore-related monzogranite during the magma’s evolution. The discovery of the Gariatong Rb deposit suggests that the Central Lhasa terrane may be an important region for rare metal mineralization. 相似文献
3.
Xiang Jie Xiao Keyan Carranza Emmanuel John M. Chen Jianping Li Shi 《Natural Resources Research》2020,29(1):395-414
Natural Resources Research - In the past few decades, a variety of data-driven predictive modeling techniques has led to a dramatic advancement in mineral prospectivity mapping (MPM). The random... 相似文献
4.
赣西北矿集区是中国重要的花岗岩型锂矿资源基地,以发育多期次多阶段岩浆作用和大规模锂等稀有金属矿床著称。区内花岗质岩浆与稀有金属成矿关系密切,为进一步研究该地区花岗质岩浆演化特征及其与稀有金属成矿的联系,确定相关花岗岩成岩时代及成因类型,查明稀有金属成矿机制,笔者选择九岭地区狮子岭花岗岩作为研究对象,对其开展了岩相学、锆石U-Pb年代学及岩石地球化学分析。结果显示,狮子岭花岗岩属高钾钙碱性系列,具有高Si,富P,贫Ca、Mg、Fe,富集U、Hf等高场强元素,亏损Ba、Sr等大离子亲石元素,稀土元素总量较低（ΣREE=2.12×10-6~146.24×10-6）,轻稀土元素相对富集（LREE/HREE=3.5~16.53）,弱Eu负异常（δEu=0.23~0.59）的特征。整体上具有S型花岗岩的地球化学特征。锆石U-Pb定年显示,黑云母二长花岗岩成岩年龄为（141.02±0.59）Ma,锂（白）云母碱长花岗岩成岩年龄为（113.96±0.72）Ma。锂（白）云母碱长花岗岩成岩过程中形成磷锂铝石及锂云母等含锂矿物,其成岩年龄可视为锂等稀有金属成矿年龄。该区稀有金属矿化受燕山晚期岩浆结晶分异作用及后期热液交代作用共同影响,岩浆结晶分异作用是Li、Nb、Ta成矿的决定性因素,后期热液交代作用为Li等成矿元素的二次富集提供条件。 相似文献
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四川甲基卡锂矿伟晶岩转石分布区“3定2参”大比例尺填图法及其在青藏高原应用的意义 总被引：4，自引：0，他引：4
我国西部地区无论是新疆阿尔泰还是地处青藏高原的西昆仑地区或是松潘-甘孜成矿带,都是我国伟晶岩型矿床找矿远景区,但要么剥蚀严重,要么第四系覆盖,难以找到好的地质露头。本文以地处青藏高原东南缘的川西甲基卡矿田为例,通过近10年来的实践,探索出一套在第四系覆盖严重但又有伟晶岩转石分布地区的填图找矿方法--"3定2参"1∶2000伟晶岩转石填图法,即:定伟晶岩转石类型、尺度、密度,参考矿区内伟晶岩脉产状和地形条件。实践证明,该方法能够快速有效识别伟晶岩转石类型(冰碛物、坡积物和原地或半原地型),并可进一步确定第四系覆盖区内伟晶岩脉的类型、产状及规模,为钻探工程部署提供依据。2019年在甲基卡经8个钻孔验证,在日西柯第四系覆盖区内发现16条花岗伟晶岩脉,其中锂辉石伟晶岩脉10条,实现了新的找矿突破。这一方法同样在可尔因矿集区适用,并指导2019年"松潘-甘孜成锂带锂铍多金属大型资源基地综合调查评价"项目在上述两个地区实施钻探验证,初步探获新增氧化锂资源量超过15万吨,值得进一步推广应用。 相似文献
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湖南仁里超大型钽铌矿床钽铌铍矿资源丰富,Ta2O5资源量达到了超大型规模,BeO资源量达到了大型规模。为进一步研究湖南仁里超大型钽铌矿床稀有金属的赋存特征、成矿规律及矿产资源综合利用前景,开展了地球化学分析、电子探针、包裹体、同位素测年及可选性试验等研究工作,通过系统梳理仁里超大型钽铌矿床的工作进展,进一步探讨了该矿床的下一步找矿思路。仁里钽铌矿床共(伴)生矿种多,稀有金属综合回收率及矿产资源采选综合利用率高,具有极大的开发利用价值,可作为绿色、环保、无尾矿范例进行高效勘查与开发。仁里矿区钽铌铍矿资源丰富,具有较好的找矿潜力,加大地质勘查资金投入有望取得钽铌铍锂等稀有金属找矿新进展。下一步应对矿区2、3、5、6号主矿脉深部矿体进行控制,力争取得钽铌铍矿找矿突破,同时加强对矿区西部或西南部隐伏锂辉石白云母钠长石伟晶岩的研究工作,力争取得锂辉石白云母钠长石伟晶岩型锂矿找矿突破。 相似文献
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幕阜山岩体的内、外接触带伟晶岩密集分布,具有较好的稀有金属矿成矿地质条件和找矿潜力。为了进一步研究幕阜山地区稀有金属矿的赋存特征、成矿规律及矿产资源找矿潜力,指导下一步勘查工作,系统梳理了幕阜山地区稀有金属矿勘查工作进展,将湖南境内的幕阜山地区划分为5个成矿远景区,评价了各成矿远景区的找矿潜力,进一步探讨了该地区的找矿方向。幕阜山地区的锂铌钽铍矿资源主要集中在幕阜山岩体西南缘的仁里—传梓源与上大洲—南江桥成矿远景区; 预测Ta2O5潜在资源量约40 000 t,Nb2O5潜在资源量约49 000 t,Li2O潜在资源量约320 000 t,BeO潜在资源量约48 000 t。可对幕阜山地区稀有金属找矿勘查和研究起到指导作用。 相似文献
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9.
YANG Shizhen ZHOU Fangchun LI Jianbin LIU Xiang LI Jiankang HUANG Zhibiao SU Junnan LI Peng 《中国地质调查》2014,7(4):28-36
Renli extra-large Ta-Nb deposit is rich in tantalum, niobium and beryllium resources. The Ta2O5 resource is of extra-large scale and the Ta2O5 resource reaches large scale. In order to further study the occurrence characteristics, metallogenic regularity and the prospect of comprehensive utilization of mineral resources of rare metals in Renli extra-large Nb-Ta deposit, the authors have carried out the research work of geochemical analysis, EPMA, fluid inclusion study, isotope dating and mineral processing experiment. Based on the systematic review of the research progress in Renli extra-large Ta-Nb deposit, the authors also discussed the following prospectiong ideas of the deposit. There are many associated minerals in Renli Nb-Ta deposit, and the recovery rate of rare metals and the comprehensive utilization rate of mineral resources are high. Therefore it has great value of development and utilization, and the efficient exploration and development that characterized by green, environmentally friendly and no tailings can be carried out in Renli Ta-Nb deposit as a typical example. Renli mining area is rich in tantalum, niobium and beryllium resources and has great prospecting potential. With increasing geological exploitation funding, it’s probable to make new prospecting progress of Ta-Nb-Be-Li rare metal. The next work will focus on the control of the deep ore bodies of No.2, 3, 5 and 6 main ore veins in the mining area in order to make new progress in tantalum niobium beryllium ore prospecting. The research work of concealed spodumene muscovite albite pegmatite in western or southwestern mining area will be strengthened in order to make a breakthrough in spodumene muscovite albite pegmatite type lithium ore prospecting. 相似文献
10.
《Journal of Asian Earth Sciences》1999,17(5-6):683-702
The Thakkhola–Mustang graben is located at the northern side of the Dhaulagiri and Annapurna ranges in North Central Nepal. The structural pattern is mainly characterised by the N020–040° Thakkhola Fault system responsible for the development of the half-graben. A detailed study of the substrate and the sedimentary fill in several outcrops indicates polyphased faulting:-pre-sedimentation faulting (Miocene), with a mainly NNW–SSE to N–S compressional stress expressed in the substratum by N020–040° and N180–N010° sinistral and N130–140° dextral conjugate strike-slip faults;-syn-sedimentation faulting (Pliocene–Pleistocene), characterised by a W–E to WNW–ESE extensional stress and tectonic subsidence of the half-graben during the Tetang period (Pliocene probably), followed by a doming of the Tetang deposits and a short period of erosion (cf. Pliocene planation surface and unconformity between the Tetang and Thakkhola Formations); the Thakkhola period (Pleistocene) is characterized by a W–E to WNW–ESE extensional stress and a major subsidence of the half graben;-post-sedimentation recurrent extensional faulting and N–S and NE–SW normal faults in the late Quaternary terrace formations.Geodynamic interpretation of the faulting is discussed in relation to the following:
- 1.the geographic situation of the Thakkhola–Mustang half-graben in the southern part of Tibet and its setting in the Tethyan series above the South Tibetan Detachment System (STDS);
- 2.the geodynamic conditions of the convergence between India and Eurasia and the dextral east–west shearing between the High Himalayas and south Tibet;
- 3.the possible relations between the sinistral Thakkhola and the dextral Karakorum strike-slip faults in a N–S compressional stress regime during the Miocene.