Characteristics of tectonic deformation of the melange zone in the Lachlan Orogen along eastern coast of Australia

作者：Dong-sheng Wang,Zong-qi Wang,Gang Wang,Xian-qing Guo,Yu-dong Wu

摘要：The Narooma-Batemans Bay(NBB)area along the southeast coast of Australia is a part of the eastern zone of the Early Paleozoic Lachlan Orogen.In the NBB,a set of rock association consisting of turbidites,siliceous rock,basic lava,and argillaceous melange zone is mainly developed.According to systematic field geological survey,the deformation of 3 stages(D1,D2,and D3)was identified in the NBB.At stage D1,with the original bedding S0 in a nearly east-west trending as the deformation plane,tight folds,isoclinal folds,and other structures formed in the NBB accompanied by structural transposition.As a result,crenulation cleavage developed along the axial plane of the folds and schistosity S1 formed.At stage D2,with north-south-trending schistosity S1 as the deformation plane,a large number of asymmetrical folds and rotated porphyroclasts formed owing to thrusting and shear.At stage D3,leftlateral strike-slip occurred along the main north-south-trending schistosity.Based on the analysis of the characteristics of tectonic deformation in the NBB and summary of previous research results,it is determined that the early-stage(D1)deformation is related to Ordovician Macquarie arc-continent collision and the deformation at stages D2 and D3 is the result of the westward subduction of Paleo-Pacific Plate.That is,it is not the continuous westward subduction of the Paleo-Pacific Plate that constitutes the evolution model of the NBB as previously considered.

發文機構：Ministry of Natural Resources Key Laboratory of Metallogeny and Mineral Assessment

關鍵詞：AUSTRALIANarooma-BatemansBayMelangesTectonicdeformationLachlanOROGENEarlyPALEOZOICArc-continentcollision

分類號： P54[天文地球—構造地質學][天文地球—地質學]