| Geochemistry of meta-volcanic rocks from the Longbohe Cu deposit, Yunnan Province, China： Implications for the genesis and tectonic setting |
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| 作者姓名： | CUI Yinliang QING Dexian CHEN Yaoguang |
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| 作者单位： | CUI Yinliang1，2，QING Dexian1，and CHEN Yaoguang2 1 Land and Mineral Resource Engineering College of Kunming University of Science and Technology，Kunming 650093，China 2 Yunnan Nonferrous Metals Geological Bureau，Kunming 650051，China |
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| 摘 要： | The Longbohe Cu deposit, which is located in the southern part of the Honghe ore-forming zone, Yunnan Province, China, belongs to a typical ore field where volcanic rocks are of wide distribution and are associated with Cu mineralization in time and space. The volcanic rocks in the ore field, which have experienced varying degree of alteration or regional metamorphism, can be divided into three types, i.e., meta-andesite, meta-subvolcanic rock and meta-basic volcanic rock in accordance with their mineral assemblages. These three types of volcanic rocks in the ore field are relatively rich in Na and the main samples plot in the area of alkali basalts in the geochemical classification diagram. With the exception of very few elements, these three types of volcanic rocks are similar in the content of trace elements. In comparison to the basalts of different tectonic settings, the meta-volcanic rocks in the ore field are rich in high field strength elements (HFSE) such as Th, Nb, etc. and depleted in large ion lithophile elements (LILE) such as Sr, Ba, etc. and their primary mantle-normalized trace element patterns show remarkable negative Th and Nb anomalies and negative Sr and Ba anomalies. These three types of volcanic rocks are similar in REE content range and chondrite-normalized REE patterns with the exception of Eu anomaly. Various lines of evidence show that these three types of volcanic rocks in the ore field have the same source but are the products of different stages of magmatic evolution, their original magma is a product of partial melting of the metasomatically enriched mantle in the tensional tectonic setting within the continent plate, and the crystallization differentiation plays an important role in the process of magmatic evolution.
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| 关 键 词： | 地球化学 火山岩石 铜 矿石 |
| 修稿时间： | 2006-04-172006-06-20 |
Geochemistry of meta-volcanic rocks from the Longbohe Cu deposit,Yunnan Province,China: Implications for the genesis and tectonic setting |
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| CUI Yinliang QING Dexian CHEN Yaoguang.Geochemistry of meta-volcanic rocks from the Longbohe Cu deposit,Yunnan Province,China: Implications for the genesis and tectonic setting[J].Chinese Journal of Geochemistry,2007,26(3):312-324. |
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| Authors: | Cui Yinliang Qing Dexian Chen Yaoguang |
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| Institution: | (1) Land and Mineral Resource Engineering College of Kumming University of Science and Technology, Kunming, 650093, China;(2) Yunnan Nonferrous Metals Geological Bureau, Kumming, 650051, China |
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| Abstract: | The Longbohe Cu deposit, which is located in the southern part of the Honghe ore-forming zone, Yunnan Province, China, belongs to a typical ore field where volcanic rocks are of wide distribution and are associated with Cu mineralization in time and space. The volcanic rocks in the ore field, which have experienced varying degree of alteration or regional metamorphism, can be divided into three types, i.e., meta-andesite, meta-subvolcanic rock and meta-basic volcanic rock in accordance with their mineral assemblages. These three types of volcanic rocks in the ore field are relatively rich in Na and the main samples plot in the area of alkali basalts in the geochemical classification diagram. With the exception of very few elements, these three types of volcanic rocks are similar in the content of trace elements. In comparison to the basalts of different tectonic settings, the meta-volcanic rocks in the ore field are rich in high field strength elements (HFSE) such as Th, Nb, etc. and depleted in large ion lithophile elements (LILE) such as Sr, Ba, etc. and their primary mantle-normalized trace element patterns show remarkable negative Th and Nb anomalies and negative Sr and Ba anomalies. These three types of volcanic rocks are similar in REE content range and chondrite-normalized REE patterns with the exception of Eu anomaly. Various lines of evidence show that these three types of volcanic rocks in the ore field have the same source but are the products of different stages of magmatic evolution, their original magma is a product of partial melting of the metasomatically enriched mantle in the tensional tectonic setting within the continent plate, and the crystallization differentiation plays an important role in the process of magmatic evolution. |
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| Keywords: | meta-volcanic rock geochemistry Longbohe Cu deposit Yunnan Province China |
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