华东地质2026，Vol.47Issue(2)：266-280,15.DOI:10.16788/j.hddz.32-1865/P.2024.11.001
滇东南里呼地区中—晚二叠世洋中脊玄武岩的发现及其对区域构造环境的指示
Discovery of Middle-Late Permian mid-ocean ridge basalts(MORB)in Lihu,Southeast Yunnan and its regional tectonic implication
摘要
Abstract
There has been a significant controversy for a long time regarding the paleogeographical environ-ment of the Carboniferous-Permian period in the southeastern Yunnan region.One viewpoint holds that it be-longs to the platform facies,while another contends that it is of the basin facies.This controversy has severely re-stricted the in-depth understanding of the tectonic evolution of the Youjiang Basin.Through a 1∶50 000 regional geological survey,a set of pillow basic volcanic rocks from the Middle-Late Permian period was discovered in the Lihu area,Funing County,southeastern Yunnan.Its main lithologies include dense massive basalt,spherulitic(pi-critic)basalt interbedded with basaltic volcanic breccia.The chondrite-normalized rare earth element distribution curves of these volcanic rocks are flat,similar to the characteristics of the E-MORB.On the primitive mantle-nor-malized trace element spider diagrams,the rocks show relatively enriched elements such as K,Rb,Ba,and Th,while elements like Ti and P are relatively depleted.In the tectonic setting diagrams,the projection points of these rocks fall into the ocean ridge and ocean floor area,as well as the oceanic ridge tholeiite area respectively,gener-ally exhibiting the characteristics of high-potassium tholeiite of the ocean ridge.Based on this,it is believed that this set of volcanic rocks from the Middle-Late Permian period is the product of the rapid expansion of the You-jiang Ocean Basin.Combining with previous research results,it is speculated that the southeastern Yunnan region should have been a multi-island ocean basin environment composed of stable shallow-water sediments,oceanic is-lands,deep-water areas,and the open ocean basin during the Late Paleozoic era.This discovery provides impor-tant reference materials for the tectonic evolution of the Youjiang Ocean Basin.关键词
火山岩/洋中脊玄武岩/多岛洋盆/中—晚二叠世/滇东南地区Key words
volcanic lava/mid-ocean ridge basalt/multi-island ocean basin/Middle-Late Permian/south-eastern Yunnan region分类
天文与地球科学引用本文复制引用
赵云江,钟春荣,包佳凤,李维科,何世军,刘军平,李序贵,魏思礼..滇东南里呼地区中—晚二叠世洋中脊玄武岩的发现及其对区域构造环境的指示[J].华东地质,2026,47(2):266-280,15.基金项目
云南省技术创新人才培养对象资助项目"技术创新人才培养对象项目刘军平(编号:202305AD160031)"、云南省自然资源厅基金资助项目"云南省℃1∶5万大庄幅、法裱幅、底土幅、甸中幅区域地质调查(编号:D202207)"和云南省科学技术厅项目"滇中东川—易门地区古元古代重大构造-岩浆事件对扬子陆块早期演化的约束(编号:202401AT070012)"联合资助. （编号:202305AD160031）
