摘要
大别 -苏鲁构造带内超高压 (UHP)和高压 (HP)变质岩石的分布和不同构造岩石单位间的关系表明 ,三叠纪中朝与扬子克拉通碰撞及超高压和高压变质岩石形成时的古缝合线 ,位于大别地块的北缘 ,沿八里畈—磨子潭—晓天一线展布 ,在苏鲁地区 ,五莲 -烟台断裂代表被强烈改造了的古缝合线的位置 .大别山北部霍山县与岳西县交界地区以及舒城、桐城和潜山县交界地区UHP和HP单位岩石的大面积分布 ,说明水吼 -五河断裂不是UHP和HP榴辉岩相岩石的北限 ,因而 ,不代表缝合线位置 ,“南大别”与“北大别”地体的划分地质意义是不明确的 .同时 ,大别山北部的镁铁质及超镁铁质岩石块体群 ,包括变形的方辉橄榄岩、纯橄榄岩组合及未变形的辉石岩、角闪辉石岩和辉长岩组合 ,前者与榴辉岩相岩石有相同的变形变质及几何学特征 ,后者是燕山期侵入体 (12 3～ 130Ma) ,因此 ,不是“变质蛇绿混杂岩” ,也不代表三叠纪陆 -陆碰撞时期古缝合线 .强调指出 ,准确地鉴别三叠纪碰撞缝合线位置 。
Thedistributionofultrahighpressuremetamorphic (UHPM )andhighpressuremetamorphic (HPM )rocksandthegeometricalrelationshipbetweenvariouspetrotectonicunitsintheDabie -Sulutectonic zonebothindicatethatthesuturelinethatoccurredwhentheSino -KoreanandYangtzecratonscollidedand whentheultrahighpressureandhighpressuremetamorphicrocksweregenerated ,aresituatedatthenorthern marginoftheDabiemassif.ThissuturelineisdistributedalongtheBalifan -Mozitan -Xiaotianfault,and possiblylinkedtotheWulian -Yantaifault,thepositionofthesuturelineviolentlymodifiedintheSulure gion .Thelarge_scaledistributionoftheUHPandHPmetamorphicrocksneartheboundarybetweenHuoshan CountyandYuexiCountyandintheadjacentareaofShucheng ,TongchengandQianshancountiesinthe northofDabieMountains,indicatesthattheShuihou -WuhefaultisnotthenorthernlimitoftheUHPand HPeclogitic_faciesrock .Therefore ,thisShuihou -Wuhefaultdoesnotrepresentthepositionofthesuture line .Inaddition ,thegeologicalimplicationoftheclassificationoftheterraneas“SouthernDabie”and “NorthernDabie”isnotaccurate .Atthesametime ,Themaficandultramaficrockmassgroupsincludethe deformedharzburgite ,pureperidotiteassemblageandundeformedpyroxenite ,bojiteandgabbroassemblage .Thefirsttypeofmafic_ultramaficrockbodiescontainthesamedeformedandmetamorphicandgeometrical featuresastheeclogiticfaciesrocks.Thesecondtypeofmafic_ultramaficrocksareintrusivebodiesintheYan shanianperiod ( 1 2 3- 1 30Ma) .Therefore,themafic_ultramaficrocksarenotdefinedasthe“metamorphic ophioliticm啨ｌａｎｇｅ” ,orinterpretedasthesuturelineintheTriassiccontinent_continentcollisionperiod .Itis emphasizedthattheaccurateidentificationofthepositionoftheTriassiccollisionsuturelineisthekeytothe correctunderstandingoftheformationandreciprocaldynamicprocessoftheUHPandHProcks.
出处
《地球科学（中国地质大学学报）》
EI
CAS
CSCD
北大核心
2000年第2期111-116,共6页
Earth Science-Journal of China University of Geosciences
基金
国家自然科学基金!资助项目 (No .49972 0 67
No .497940 41和No .49772 14 6)
