福建地质
福建地質
복건지질
GEOLOGY OF FUJIAN
2011年
4期
327-334
,共8页
同位素地质年代%复式岩体%漳浦
同位素地質年代%複式巖體%漳浦
동위소지질년대%복식암체%장포
Isotopic Geology%Complex%Zhangpu
漳浦复式岩体位于长乐一南澳断裂带南段，是一个大型的燕山期复式岩体。前人将该复式岩体划分为早侏罗世、晚侏罗世、早白垩世早期、早白垩世晚期、晚白垩世等5期侵入岩。其中，早侏罗世、晚侏罗世、早白垩世早期侵入岩都具有韧性变形、变质的特征，而早白垩世晚期、晚白垩世侵人岩则未发生韧性变形、变质作用。通过对变质侵入岩锆石微区（LA—ICPMS）U—Pb同位素测年研究，结合侵入体之间及其与围岩的接触关系等特征，认为原划为早侏罗世的变质花岗闪长岩（龙海白坑岩体）的时代应为晚侏罗世早期（149．9Ma，LA-ICPMS锆石U—Pb），原定为晚侏罗世古美山序列的变质花岗闪长岩、二长花岗岩、正长花岗岩属晚侏罗世晚期（137～145．4Ma，LA—ICPMs锆石U-Pb），而原划分为早白垩世早期漳浦序列的变质石英闪长岩、花岗闪长岩、二长花岗岩、正长花岗岩应当与以早白垩世漳州序列的相应岩类为同期产物，属早白垩世（106．7Ma，LA—ICPMS锆石U—Pb），是长乐-南澳断裂带受变质变形的产物。
漳浦複式巖體位于長樂一南澳斷裂帶南段，是一箇大型的燕山期複式巖體。前人將該複式巖體劃分為早侏囉世、晚侏囉世、早白堊世早期、早白堊世晚期、晚白堊世等5期侵入巖。其中，早侏囉世、晚侏囉世、早白堊世早期侵入巖都具有韌性變形、變質的特徵，而早白堊世晚期、晚白堊世侵人巖則未髮生韌性變形、變質作用。通過對變質侵入巖鋯石微區（LA—ICPMS）U—Pb同位素測年研究，結閤侵入體之間及其與圍巖的接觸關繫等特徵，認為原劃為早侏囉世的變質花崗閃長巖（龍海白坑巖體）的時代應為晚侏囉世早期（149．9Ma，LA-ICPMS鋯石U—Pb），原定為晚侏囉世古美山序列的變質花崗閃長巖、二長花崗巖、正長花崗巖屬晚侏囉世晚期（137～145．4Ma，LA—ICPMs鋯石U-Pb），而原劃分為早白堊世早期漳浦序列的變質石英閃長巖、花崗閃長巖、二長花崗巖、正長花崗巖應噹與以早白堊世漳州序列的相應巖類為同期產物，屬早白堊世（106．7Ma，LA—ICPMS鋯石U—Pb），是長樂-南澳斷裂帶受變質變形的產物。
장포복식암체위우장악일남오단렬대남단，시일개대형적연산기복식암체。전인장해복식암체화분위조주라세、만주라세、조백성세조기、조백성세만기、만백성세등5기침입암。기중，조주라세、만주라세、조백성세조기침입암도구유인성변형、변질적특정，이조백성세만기、만백성세침인암칙미발생인성변형、변질작용。통과대변질침입암고석미구（LA—ICPMS）U—Pb동위소측년연구，결합침입체지간급기여위암적접촉관계등특정，인위원화위조주라세적변질화강섬장암（룡해백갱암체）적시대응위만주라세조기（149．9Ma，LA-ICPMS고석U—Pb），원정위만주라세고미산서렬적변질화강섬장암、이장화강암、정장화강암속만주라세만기（137～145．4Ma，LA—ICPMs고석U-Pb），이원화분위조백성세조기장포서렬적변질석영섬장암、화강섬장암、이장화강암、정장화강암응당여이조백성세장주서렬적상응암류위동기산물，속조백성세（106．7Ma，LA—ICPMS고석U—Pb），시장악-남오단렬대수변질변형적산물。
Zhangpu complex is a large Yanshanian periods complex, which located in southern Changle-Nan＇ao fault zone. The previous studies suggested that the complex are composed of early Jurassic, late Jurassic, late Jurassic-early Cretaceous, early Cretaceous and late Cretaceous five periods intrusive rocks. Early Jurassic, late Jurassic, late Jurassic-early Cretaceous intrusive rocks have characteristic of plastic deformation and metamorphic; Eearly Cretaceous and late Cretaceous intrusive rocks, contrariwise, have not characteristic of plastic deformation and metamorphic. By LA-ICPMS U-Pb chronological study of zircons, Considering the geological characteristics of complex, it is believed that the metamorphic granodiorite of Baikeng intrusive, which was divided into early Jurassic periods, is dated at 149.9 Ma using the LA-ICPMS zircon U-Pb method and represents product of the early-late Jurassic magmatism, and the metamorphic Gumeishan sequence belong to the late-late Jurassic periods, which is date at 137-145.4 Ma, and the metamorphic Zhangpu sequence belong to the early Cretaceous periods, which is date at 106.7 Ma. Zhangpu sequence is the product of the early Cretaceous magmatism which forms Zhangzhou sequence, is deformated and metamorphic in the Changle-Nan＇ao fault zone.
