黔东北新元古代陡山沱期宏体藻类的固着器特征及其沉积环境意义

THE HOLDFASTS OF MACROALGAE IN THE NEOPROTEROZOIC DOUSHANTUO FORMATION IN NORTHEASTERN GUIZHOU PROVINCE AND THEIR ENVIRONMENTAL SIGNIFICANCE

产于贵州江口新元古界陡山沱组上部黑色碳质泥岩和硅质泥岩中的宏体生物群,多数为发育固着器的固着底栖生物。宏体藻类固着器的形态和保存方式可提供生物群生活环境和埋藏环境的信息。黔东北陡山沱期宏体生物群生活于相对平静、较为清澈的水体之中,固着基底为富含水份的粥性基底。可能与洋流有关的水流事件将宏体藻类折断或“连根”拔起;水流事件之后,沉积物将宏体藻类的遗体掩埋于还原性较强的环境之中,新生的和水流事件未致死亡的宏体生物在新的沉积物表面上继续生长。

Most macro-organisms were found in carbonaceous and siliceous mudstones of the upper part of the Neoproterozoic Doushantuo Formation in Jiangkou County, Guizhou Province. They are considered to live on the sea floor by their holdfasts. The appearance and preserved mode of the holdfasts may provide some information about the living and burial environment of macrobiota. This study shows that the Doushantuo macrobiota in northeastern Guizhou Province lived in a relative quiet environment with clear water; the ground that the macroalgae were living on could be a porridgelike one; and the macroalgal holdfasts could be pulled out from the porridgelike ground and the foliates of megascopic algae could be folded by the current events related to ocean currents. After the current event, the macroalgal corpses were covered in a reductive environment by deposits. Then the new community including new and surviving macroalgae continues to live on the new depositional surface.