摘要
中国东南沿海中、新生代火山-侵入杂岩带，是环太平洋构造一岩浆成矿带的重要组成部分之一。分布总面积约30万km2，火山活动时间从早三叠世到第四纪。该岩带基底由杨子板块、华夏板块和海南板块等三个一级大地构造单元组成。该区中、新生代构造一岩浆活动可根据其地区差异，构造环境、岩浆源区性质与基底构造背景不同等因素，以主要区域深大断裂为界，划分为浙东—闽东、浙西—赣东北、闽西—赣中、粤东、粤西—桂东南、雪球及台湾等7个构造—岩浆活动区。火山岩可分为三个火山岩系，共9个火山旋回。早中生代火山宕系包括了3个火山旋回；第一旋回（T）为一套海相英安质和低硅流纹质火山岩；第二旋回（J1）与第三旋回（J2）均为一套双峰式岩石组合，为较典型的拉张应力环境中的火山产物。晚中生代火山岩系包括4个火山旋回；第一旅回（J3）和第二旋回（J）以英安质和流纹质火山岩占绝对优势，它们构成了东南沿海火山一侵人杂岩的主体；第三旅回（K1）与第四旅回（K2）火山岩总体属高钾钙碱系列，并具向碱性系列过渡特征，火山岩产生于弱拉张环境。新生代火山岩系包括两个火山旋回；第一旋回（E－N）火山岩可分为超基性岩，基性岩、碱性中性岩、碱性岩及酸性岩五大类，其产出多受NE、NW及EW向王组断裂构造?
Mesozoic-Cenozoic volCanic-intrusive complex rock belt of southeast coast of China is oneof the important component parts of the circum-Pacific tectonicwmagmatic mincralization belt.During the period of about 1. 600 Ma from Precambrian to Triassic. the area involved JinningCaledonian and Hercynian-Indosinian tectonomagmatic activities. The basement of volcanic series is consisted of three first-order tectonic units-Yangtze,Cathaysian and Haindn plates. According to the regiona1 diversity,tectonic environment,nature of magma source .basement tectonic setting and other factors,the area may be divided into 7 tectonomagmatic activity regionsbounded among them by major regional deep faults,i. e., East Zhejiang-East Fujian region,West Zhejinag -Northeast Jiangxi region, West Fujian - Middle Jiangxi region, East Guangdong region, West Guangdong -Southeast Guangxi region, Leizhou (pcninsula ) - Hainan (island )region and Taiwan region.The Mesozoic-Cenozoic volcanic-intrusive complex rocks of the belt cover an arca of about3, Oookm2. In the east part of the area including East Zhejiang,East Fujian and East Guangdong Provinces,the volcanic-intrusive rocks are distributed continuously in the form of vast areas and belts; whereas in the west part including West Zhejiang, West Fujian, West Jiangxi,West G uangdong and Southeast Guangxi Provinces, they are distributcd 1imitedly,showing theform of isolated basins or intrusive bodies. Judging from distribution scalcs of volcanic rocks(they have morc scales in east than in west ),thickness of layers (they are thicker in east thanin west) and facies characteristiCS (pyroclastic flow facies are dominated in east while sedimentary facies are mostly in west ), the scales and intensities of Mesozoic volcanic activities werestrengthened from west to east.The Mesozoic -Cenozoic volcanic-intrusive activities started at early Triassic and terminated at Quaternary. Overall, they showed a gradual migration from south to north and fromwest to east, being coincide with the dual migration parallel and vertical to the volcanic belts ofthe huge West Pacific volcanic belt. The volcanic rocks may be divided into early Mesozoic,lateMesozoic and Cenozoic volcanie series and 9 volcanic cycles.The early Mesozujc volcanic series includes 3 volcanic cycles. The first cycle (T ) presentsa suite of marine dacitic and low-silicic rhyolitic volcanic rocks. The second one (J1) and thcthird one (J2) are all bimodel assembleges,representing typical products formed in the stresscnvironment of extension and controlled by EW-trending tectonics.The late Mesozoic volcanic series includes 4 volcanic cycles. The first cycle (J) and thesecond cycle (J) are predominated by dacitic and rhyolitic volcanic rocks charactered byhigh-silicic and high-potassium compositions, representing products formed in the stress environment of relaxation after regional compression, their distributions are COntrolled by NEtrending tectonics and they form the major part of the southeast coastal VolCaniC-intrusive comp1ex rock belt. The voicaniC rocks of the third cycle (K1) and the fourth Cycle (K2) belong to,on the whole, the high-potassium ds-alkdrie serthe being transittrial to alkaline series, theyare formed in the stress environment of weak extension and controlled dually by NE and NWtrending tectonics but mainly by NE-trending tectonics.The Cenozoic volcanic series includes 2 cycles. The volcanic rocks of the first cycle (E-N )may be divided into 5 types, i. e., ultrabasic rocks, basic rocks, alkaline-medium rocks, alkaline rocks and acidic rocks. Their distributinns are controlled by NE,NW and EW-trendingfdults. The volcanic rocks of the second cycle (Q ) are limited only in Leishou-Hainan andTaiwan regions,which may be divided into ultrabasic and basic types. Their occurrences are directly related to the activities of plate tectonics.
出处
《火山地质与矿产》
1997年第3期167-190,共24页
Volcanology & Mineral Resources
关键词
火山岩
火山侵入杂岩
火山旋回
新生代
中生代
volcanic rock volcanic-intrustive complex volcanic cycle volcanic series Mesozoic-Cenozoic tectonomagmatic activity region southeast coast
