摘要
过去视为浅水沉积的“芬卡苏砾岩”,实为深水海底水道中的重力流及其伴生沉积。识别出5种重力流沉积相:(1)含砾泥岩相,(2)富基质砾岩相,(3)贫基质砾岩相,(4)块状砂岩相,(5)递交砂岩相。其中(1)和(2)为碎屑流沉积,(3)和(4)属颗粒流沉积,(5)为浊积岩,包括高密度和低密度浊流沉积。与其伴生的相有:(6)暗色泥质岩相:悬浮沉积,(7)扭曲层相:滑塌沉积,(8)双向交错纹理砂岩相:内潮汐沉积,(9)单向交错层-交错纹理砂岩相:叠加有内波作用的内潮汐沉积。上述九种相构成了5个有规律的组合,反映海平面持续上升,物源区不断远离沉积区的过程。
Abstract
Fincastle Conglomerate which was considered as deposits in shallow water in the pastis mainly gravity flow deposits and associated sediments ia deep water submarine chan-nels.Five gravity flow facies have been recognized:1.pebbly mudstone facies;2.matrix-rich conglomerate facies;3.matrix-poor conglomerate facies;4.massive sandstone facies;5.graded sandstone facies.Among them 1 and 2 are debris flow deposits;3 and 4 belongto grain flow deposits;and 5 is turbidite including high density and low density currentdeposits.The associated facies comprise:6.dark shale and mudrock facies:suspension de-posit;7.contorted bed facies:slumping deposit;8.bidirectional cross-laminated sandstonefacies:internal-tide deposit;9.unidirectional cross-bedded and cross-laminated sandstonefacies:deposit of internal tide with superposing internal wave.The nine facies mentionedabove constitute five facies assemblages that show regular patterns.To sum up,the Fin-castle Conglomerate shows a clear upward-fining sequence,reflecting a process of that thesea level continued to rise and the source area was farther and farther to the sedimentarysite.
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