山东沂蒙山世界地质公园前寒武纪侵入岩地质特征和形成时代

Geological Characteristics and Formation Age of Precambrian Intrusive Rocks in Yimengshan World Geopark in Linyi City in Shandong Province

摘要:

沂蒙山世界地质公园位于山东临沂地区，主要由新太古代不同时期（变质）侵入岩构成。本文总结了沂蒙山世界地质公园内主要早前寒武纪侵入岩单元的地质特征和锆石SHRIMP UPb定年结果。蒙山西北部出露的新太古代早中期侵入岩有3种，平邑县九女关出露的泰山序列望府山单元条带状英云闪长质片麻岩地质测年为2694Ma，平邑县白马关出露的泰山序列西官庄单元英云闪长质片麻岩地质测年为2694Ma，平邑县大望山出露的新甫山序列上港单元奥长花岗伟晶岩年代为2606Ma。蒙山南部龟蒙顶出露的新太古代晚期峄山序列龟蒙顶单元片麻状花岗闪长岩地质测年为2539Ma、2544Ma。蒙山东部孟良崮出露的新太古代晚期傲徕山序列蒋峪单元条带状黑云母二长花岗岩年代为2518Ma。蒙山北部云蒙峰出露的傲徕山序列松山单元中粒二长花岗岩地质测年为2534Ma。泰山序列英云闪长质片麻岩具新生陆壳性质，部分新甫山序列奥长花岗岩是英云闪长质片麻岩深熔作用产物；峄山序列TTG片麻岩是新生岩浆混入地壳物质形成的。云蒙峰岩体属傲徕山岩套二长花岗岩，为陆壳物质重熔（深熔）作用形成的。

Abstract:

Mengshan World Geopark is located in Linyi area in Shandong Province. It is mainly composed of metamorphic intrusive rocks from different periods of Neoproterozoic era. In this paper, geological characteristics and zircon SHRIMP UPb dating results of main early Cambrian intrusive rock units in Yimengshan World Geopark have been summarized. There are three types of Neoarchean early middle intrusive rocks exposed in the northwest of Mengshan Mountain. The age of banded tonalitediorite gneiss in Wangfushan unit of the Mount Taishan sequence exposed in Jiunvguan in Pingyi county is 2694Ma. The age of tonalitediorite gneiss in Xiguanzhuang unit of the Mount Taishan sequenceexposed in Baimaguan in Pingyi county is 2694Ma. The age of trondhjemite pegmatite of Shanggang unit in Xinfushan sequence exposed in Dawangshan in Pingyi county is 2606Ma. The age of gneissic granodiorite pluton of Guimengding unit in late Neoarchean Yishan sequence exposed at Guimengding in the southern part of Mengshan is 2539Ma and 2544Ma respectively. The age of banded biotite diorite granite of Jiangyu unit in late Neoarchean Aulaishan sequence exposed at Menglianggu in the eastern part of Mengshan is 2518Ma. The age of medium grain diorite granite of Songshan unit in Aolaishan sequence exposed at Yunmeng Peak in the northern part of Mengshan is 2534Ma. The banded tonalitediorite gneiss of Mount Taishan sequence has the nature of a new continental crust, and part of Xinfushan sequence trondhjemite is the product of anatexis of tonalite gneiss. TTG gneiss in Yishan sequence is formed by the mixing of newly formed magma with crustal material. Yunmengfeng rock belongs to diorite granite of Aolaishan suite. It is formed by the remelting (deep melting) of continental crustal materials.