赣北:华南地质之窗

North Jiangxi:A Geological Window of South China

研究发现,江西北部宜丰-德兴一带下扬子陆块南缘的九岭、万年推覆体与晚古生代以来的沉积盖层之下,隐伏着华南洋对接带和新元古代晚期至早古生代深水裂谷海槽形成的造山带。造山带两侧分别为下扬子地块和华夏陆块残留的信江钱塘地块。扬子陆缘860Ma前的中新元古代地质体和华夏陆缘信江钱塘地块西南部在这里遭到消减叠覆。直至中生代时,该坳陷北部又被九岭逆冲推覆体叠覆近半。这样强烈的造山作用,颠复了"江南古陆"的传统认识。从这扇窗口,窥视了华南大陆深层次地质构造的复杂性及其与大规模成矿作用的密切联系。

This study found out that the South China sea junction belt and the orogenic belt formed from the deep-water rift trough from Late Neoproterzoic to Early Palaeozoic Era are concealed below the Jiuling and Wannian thrust nappes and the sedimentary covers since Late Palaeozoic Era.On both sides of the orogenic belt are respectively the Low Yangtze Block and the Xinjiang—Qiantang Block,the residual Cathaysian Block.The Meso-Neoproterozoic geological bodies（about 860 Ma ago）in the Yangtze continent margin and the southwestern part of Xinjiang—Qiantang block of the Cathaysian continent margin were all subducted and overlapped here.It was until Mesozoic Era,about a half of the northern part of the depression was not overlapped by the Jiuling thrust nappe.Therefore strong orogenesis has completely changed the traditional concept of＂Jiangnan Ancient Land＂.It is through the window that we can catch a sight of connection between the complexity of deep-seated geological structures and large-scale of mineralization in the South China Continent.