湘桂地区泥盆纪岩相古地理重建

Reconstruction of Devonian Lithofacies Palaeogeography in Hunan and Guangxi Provinces

湘桂地区泥盆系构造上处于多种构造体系交切复合部位,发育了中国南方独特的"台—槽—丘—盆"沉积建造,泥盆系剥蚀改造严重,现今仅残留于湘中拗陷、桂中拗陷中部和西部、南盘江拗陷、黔西南拗陷以及十万山盆地等区域。通过残留地层的各种沉积相标志研究,在研究区识别出以海相环境为主的9种沉积相类型。通过沉积环境差异对比发现,南盘江拗陷与桂中拗陷以槽—台沉积体系为主,湘中拗陷以大面积碎屑潮坪—局限(开阔)台地体系为主,十万山盆地则主要发育欠补偿型盆地,总结出研究区的沉积模式表现为"槽围台,槽相连"的特征,研究区沉积演化的相分异程度与本区发育的构造和岩浆活动具有较好的沉积响应关系。

The regions of Hunan and Guangxi, which were in the composite position intersected by a variety of Tectonic systemin Devonian, and developed a unique ＂platform- depression-dome-basin＂ sedimentary system. Formation of Devonian were eroded badly in Hunan and Guangxi Provinces, which merely remained in Nanpanjiang depression, Qianxinan depression, mid- dle and west of the Guizhong depression, Shiwanshan Basin and Xiangzhong depression. Researching on various sedimentary facies symbol in residual formation, 9 types of sedimentary facies were recognized, which dominated in the marine environ- ment. The followed conclusions were obtained from the difference comparison of sedimentary environment： Nanpanjiang depression and Guizhong depression are mainly of depression-platform sedimentary system; Xiangzhong depression is mainly of clastic tidal flat and restricted （open） platform sedimentary system, and Shiwanshan basin is mainly of undercompensation basin. Sedimentary mode of study area was displays the feature ＂depression surrounded platform, depression connected＂. Fa- cies differential degree of sedimentary evolution, the tectonic movement and magmatic activity have good sedimentary response relation.