北秦岭弧后盆地俯冲消减与陆壳物质再循环——桃园岩体和黄岗杂岩体的地球化学证据

张利; 王林森; 周炼

北秦岭弧后盆地俯冲消减与陆壳物质再循环——桃园岩体和黄岗杂岩体的地球化学证据

中国地质大学地球科学学院, 武汉 430074

基金项目:

国家自然科学基金项目 40073005

国家重点基础研究项目 G1999075506

详细信息

作者简介:
张利, 女, 讲师, 1970年生, 2000年毕业于中国地质大学, 获硕士学位, 现从事同位素地球化学研究工作

中图分类号: P597
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- 被引次数: 0
出版历程
- 收稿日期: 2000-05-28
- 刊出日期: 2001-01-25

SUBDUCTION OF BACK-ARC BASIN AND RECYCLING OF CRUSTAL SUBSTANCE IN NORTHERN QINLING: GEOCHEMICAL EVIDENCE OF TAOYUAN INTRUSION AND HUANGGANG INTRUSIVE COMPLEX

Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China

摘要

摘要: 对桐柏北部加里东期桃园岩体和黄岗杂岩体的地球化学研究表明, 桃园岩体形成于与洋壳消减作用有关的弧后盆地环境, 与二郎坪基性火山岩具有相同的岩浆来源.黄岗杂岩岩浆中含有一定比例的陆壳物质, 该物质来自俯冲板片上陆壳沉积物的再循环, 与二郎坪弧后盆地向北的俯冲消减有密切联系.
- 弧后盆地消减 /
- 陆壳物质再循环 /
- 桃园岩体 /
- 黄岗杂岩体 /
- 地球化学 /
- 北秦岭
Abstract: Major and trace element compositions and isotopic compositions for Taoyuan intrusion and Huanggang intrusive complex are presented in this paper. The geochemical research into the Taoyuan intrusion and Huanggang intrusive complex in the Caledonian stage, north of Tongbai shows that the Taoyuan granitic magma derived from the depleted mantle are similar to the Erlangping basic volcanic magma. The Taoyuan granites that occurred in the back-arc basin related to the subdcution of the ocean plate originated from the same magma as those of Erlangping basic volcanic rocks. The Huanggang intrusive complex, closely related to the northward subduction of the Erlangping back-arc basin, was formed in the island-arc tectonic environment. The magmas of Huanggang are mixed with a certain percentage of continental crustal substances, products of the partial melting of the mantle wedge enhanced by the fluid extracted from the subducted slab and the overlying crustal substance in the subduction process.
- back-arc basin subduction /
- recycling of crustal substance /
- Taoyuan intrusion /
- Huanggang intrusive complex /
- geochemisty /
- northern Qinling

HTML全文

图 1 北秦岭桐柏地区地质简图

内插图指示桐柏地区在秦岭-大别造山带中的位置.1.第三系和第四系; 2.信阳群; 3.二郎坪群; 4.宽坪群; 5.中元古界; 6.秦岭杂岩; 7.桐柏杂岩; 8.燕山期花岗岩; 9.加里东期花岗岩; 10.加里东超基性-基性-中酸性侵入杂岩; 11.断层和地质界线

Fig. 1. Geological sketch map of Tongbai area with insert showing the study area in Qinling-Dabie orogenic belt

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图 2 桃园岩体(黑圆点) 和黄岗杂岩体(黑方块) 化学成分Harker图

Fig. 2. Harker diagrams of Taoyuan intrusion (black dots) and Huanggang (black squares) intrusives complex

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图 3 稀土元素组成模式

A.桃园花岗岩; B.黄岗杂岩

Fig. 3. REE model diagrams

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图 4 ε_Nd (t) -[w (⁸⁷Sr) /w (⁸⁶Sr)] _t图解

黑圆点为桃园花岗岩, t=451 Ma; 黑方块为黄岗杂岩, t=429 Ma; 黑三角为二郎坪基性火山岩^[10]在相当于桃园岩体形成时的同位素特征

Fig. 4. ε_Nd (t) vs. [w (⁸⁷Sr) /w (⁸⁶Sr)] _t diagram

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图 5 岩石w (La) /w (Sm) -w (La) 图解

图中黑圆点为桃园花岗岩, 黑方块为二郎坪基性火山岩^[3], 黑三角为所测二郎坪斜长角闪岩

Fig. 5. w (La) /w (Sm) vs. w (La) diagram

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图 6 桃园岩体花岗岩类w (Rb) -w (Y+Nb) 构造环境判别图解^[8]

图中的虚线为与洋壳消减作用有关的弧后蛇绿岩套中花岗岩类的分布范围^[11].VAG.火山弧型花岗岩; ORG.洋脊型花岗岩; WPG.板内型花岗岩; SYN-COLG.同碰撞型花岗岩.

Fig. 6. w (Rb) -w (Y+Nb) tectonic setting discrimination diagrams of Taoyuan intrusion

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表 1 桃园岩体(TY)、黄岗杂岩体(HG)、二郎坪群(TB) 的主量元素、微量元素分析结果

Table 1. Major elements, trace elements of Taoyuan (TY) intrusion, Huanggang (HG) intrusive complex and Erlangping (TB) Group

表 2 桃园岩体(TY)、黄岗杂岩体(HG)、二郎坪群(TB) 同位素分析结果^*

Table 2. Isotopic compositions of Taoyuan (TY) intrusion, Huanggang (HG) intrusive complex and Erlangping (TB) Group

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