| 秦岭大别碰撞造山带根部结晶基底隆升的变质岩石学证迹 |
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| 引用本文： | 游振东,钟增球,韩郁菁,桑隆康,陈能松,张泽明.秦岭大别碰撞造山带根部结晶基底隆升的变质岩石学证迹[J].地球科学,1997,6(3). |
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| 作者姓名： | 游振东 钟增球 韩郁菁 桑隆康 陈能松 张泽明 |
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| 作者单位： | 地球科学学院 |
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| 基金项目： | 国家自然科学基金,地矿部重点科技项目 |
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| 摘 要： | 秦岭大别碰撞造山带中隆升最高的结晶基底便是大别杂岩，在超高压变质岩和某些高级变质岩中均发现典型的近等温减压（ＩＴＤ）型的退变质结构，多呈后成合晶或冠状体的形式取代或包绕原生矿物晶粒（主晶），显示退变质不平衡反应的过程．然而超高压变质岩与大别杂岩中的高级变质岩，变质地温梯度截然不同，暗示它们形成的构造条件极不相同，超高压变质岩早期由岩石圈深处（１２０ｋｍ±）折返到下地壳与那里的高级变质岩构造混合，平行并置，而后才一起隆升．退变质不平衡结构与寄主岩的面理无关，说明这种近等温的减压退变质作用发生于后造山时期近绝热条件下的隆升体制，近绝热隆升的热源可能是中生代以来大别山地区岩石圈减薄所引起
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| 关 键 词： | 碰撞造山作用，根带结晶杂岩，超高压变质，等温减压退变质，后造山隆升 |
METAMORPHIC EVIDENCES FOR THE UPLIFT OF THE ROOT ZONE CRYSTALLINE COMPLEX OF QINLING-DABIE COLLISIONAL OROGEN, CENTRAL CHINA |
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| You Zhendong,Zhong Zengqiu,Han Yujing,Sang Longkang,Chen Nengsong,Zhang Zeming.METAMORPHIC EVIDENCES FOR THE UPLIFT OF THE ROOT ZONE CRYSTALLINE COMPLEX OF QINLING-DABIE COLLISIONAL OROGEN, CENTRAL CHINA[J].Earth Science-Journal of China University of Geosciences,1997,6(3). |
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| Authors: | You Zhendong Zhong Zengqiu Han Yujing Sang Longkang Chen Nengsong Zhang Zeming |
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| Abstract: | Dabie complex is the most highly uplifted root zone crystalline complex in the Qinling Dabie collisional orogenic belt. In both of the ultrahigh pressure (UHP) metamorphic rocks and the Dabie complex typical isothermal decompressive (ITD) retrogressive textures are developed as symplectites or coronas replacing or surrounding the primary metamorphic host mineral grains. However, the great difference of the metamorphic thermal gradient of the UHP metamorphic rocks from that of the Dabie complex indicates that they were formed at different depths only because of the tectonic mixing of primarily exhumed UHP metamorphic rocks with the metamorphic rocks in the lower crust and then uplifted together to the upper level. The retrograde metamorphic textures are independent of the major foliation of the host rock, which suggests that the ITD retrogressive metamorphic process must have been formed under post orogenic nearly adiabatic uplift tectonic regime. The heat source of the adiabatic process may have been caused by the lithospheric thinning due to delamination or convection erosion since Mesozoic. |
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| Keywords: | collisional orogeny root zone crystalline complex ultrahigh pressure metamorphism isothermal decompressive retrograde metamorphism post orogenic uplift |
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