摘要
华南至少经历了4期区域规模的大陆动力学过程,除新元古代和晚中生代具有活动陆缘背景外,均在板块内部发生并完成。华夏块体是一个以新元古代岩石为主体构成的前南华纪基底,不是稳定的克拉通古陆,经历了聚合-裂解-再聚合的复杂构造演化。志留纪发生的板内碰撞-拼合事件使华夏块体与扬子块体再次缝合,形成真正统一的中国南方大陆。在震旦纪—早侏罗世期间,整个华南基本处于陆内滨海-浅海-斜坡环境,内部没有切穿岩石圈的断层,没有大规模幔源岩浆和火山喷发的记录,多次构造变形与岩浆活动均在统一的华南岩石圈之上进行。经过早—中侏罗世的构造体制转换,才演化成为晚中生代西太平洋活动大陆边缘的一部分。从早到晚,华南岩石圈经历了多期、幕式的生长,以侧向增生为主(块体拼合),垂向生长为辅(岩浆上侵)。到晚中生代,在古太平洋板块俯冲和陆内伸展的背景下,形成了独特的华南盆岭构造。长期的板内构造演化和多期的花岗岩浆活动使华南具有很好的成矿条件,成为各种矿产与资源的富集区。新元古代南华纪和晚中生代晚侏罗世—早白垩世是华南最有利的成矿期,尤以后者矿种最多、储量最大。
Studies suggest that at least four stages of regional-scale tectonic and magmatic events have taken place in the South China block, namely, geodynamic processes of Neoproterozoic and Late Mesozoic active continental margins, Early Paleozoic and Early Mesozoic intracontinental orogenies. The Cathaysia block was a pre-Nanhua basement consisting mainly of Neoproterozoic rocks in- stead of a stable old land. It experienced a complex evolution from assembly through break-up to re-assembly. The intracontinental shortening during Silurian led to the stabilization of the united South China continent. The entire South China Block was under a shore-shallow sea-slope setting, with no translithospheric fault, no regional-scale volcanism and mantle-derived magmatism in the period fi＇om Sinian to Jurassic, during which polyphase tectonic and magmatic events occurred in the united South China lithosphere. It evolved into a part of the Late Mesozoic Western Pacific active continental margin after the Early-Middle Jurassic transformation from Tethysian to Pacific tectonic regimes. The South China lithosphere experienced polyphase continental growth due to the domi- nant lateral accretion of block assembly accompanied by vertical growth of magma up-swarming. During the Cretaceous, the South China basin and range tectonics occurred hi the western shore of the Pacific Ocean due to strong intracontinental extension caused by the northwestward subduction of the Pacific Ocean. Long-term intraplate tectonism and polystage granitic magmatism provided South China with a favorable condition of metalliz^tion, forming various large-size ore deposits and resources. Neoproterozoic Nanhua Peri-od and Early Cretaceous were two dominant stages of metallization, with various types of ore deposits being chiefly formed in the Ear- ly Cretaceous period.
出处
《地质通报》
CAS
CSCD
北大核心
2012年第7期1035-1053,共19页
Geological Bulletin of China
基金
国家重大基础研究"973"项目<华夏地块中生代陆壳再造与巨量金属成矿>(编号:2012CB416701)
国家自然科学基金项目<华南东段晚古生代-早中生代构造特征
变形运动学与年代学研究>(批准号:40972132)
<华南武夷-诸广-武功地区加里东期构造作用和大陆动力学演化>(批准号:40634022)
内生金属矿床成矿机制研究国家重点实验室项目(编号:2008-I-01)
关键词
板块构造
陆内造山
岩浆活动
成矿作用
构造演化
华南
plate tectonics
intracontinental orogeny
magmatism
metallization
tectonic evolution
South China
