福建晚中生代兜岭群时代与区域地层对比

Age and stratigraphic correlation of Late Mesozoic Douling Group in Fujian

中国东部晚中生代广布的陆相火山盆地沉积,由于海相生物化石的匮乏造成与层型地区对比的困难,长期以来该地层时代仅笼统被认为属于晚侏罗世—早白垩世。通过岩石组合、构造层和沉积构造环境的综合对比,确立闽西地区的兜岭群与闽东地区南园群、浙西建德群可以对比,构造不整合面代表区域上由挤压向拉张构造背景转化的相对等时界面。兜岭群的植物群Cupressinocladus--Brachyphyl-lum组合可能与北方的Ruffordia--Onychiopsis植物组合大体相当,叶肢介、介形类、腹足类和双壳类等化石与浙江早白垩世建德生物群、北方的热河生物群均可以对比,时代应为早白垩世欧特里夫期—阿普特期。

There were widespread depositions of terrestrial volcano basins in East China during Late Mesozo- ic. Owing to the deficiency of marine fossils, it was difficult to correlate with the stratotype area, so these strata in East China have been generally regarded as the Late Jurassic and Early Cretaceous for a long time. Through the sys- timatic correlation of rock assemblage, tectonic layer and sedimentary environment, the authors confirmed that the Douling Group in western Fujian can correlate with Nanyuan Group in eastern Fujian and Jiande Group in westem Zhejiang. The unconformity represents the relative isochronal interface when tectonic setting changed from compres- sional to tensssional in the region. The Cupressinocladus-Brachyphyllum plant assemblage of Douling Group may correlate with Ruffordia-Onychiopsis assemblage of North China, and the fossils of Conchostraca, Ostracoda, Gas- tropoda and Bivalves also can correlate with the Jiande biota of Zhejiang and Jehol biota of North China with the age of Hauterivian to Aptian in Early Cretaceous.