Recognition and Significance of Paludal Dolomites: Late Mississippian, Kentucky, USA
Recognition and Significance of Paludal Dolomites: Late Mississippian, Kentucky, USA
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帕鲁达尔白云岩的识别和意义：美国肯塔基州密西西比晚期
DOI：
10.1002/9781118485347.ch19
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发表时间：
2013
期刊：
影响因子：
0.8
通讯作者：
S. Crowley
中科院分区：
文献类型：
--
作者：
A. Barnett;V. Wright;S. Crowley
与古土壤相关的橙色至棕褐色风化二铁白云岩是美国东部肯塔基州密西西比期晚期（布里甘期）循环冰室坡道序列的一个体积较小但显着的特征。含铁白云岩具有尖锐的底部和顶部，并夹有成土单元（例如钙质结石）或洪泛区沉积物。沉积学和 C/O 稳定同位素数据表明白云岩是在咸水或裂盐沿海沼泽（沼泽）环境中形成的。本章确定了这些含铁白云石层的起源，记录了它们的层序地层意义，并提请人们注意潜在广泛但很少记录的地下暴露特征。与发育良好的古土壤和主要（密尔级）不整合相关的沼泽白云岩层可能反映了三级低位期间发生的抑制的米兰科维奇带海平面振荡。
Orange to tan weathering ferroan dolomites associated with palaeosols are a volumetrically minor but conspicuous feature of cyclic late Mississippian (Brigantian) icehouse ramp successions in Kentucky, eastern USA. The ferroan dolomites have sharp bases and tops and are intercalated with pedogenic units (e.g. calcretes) or floodplain deposits. Sedimentological and C/O stable isotope data suggest that the dolomiteswere formed in brackish or schizohaline coastal marsh (paludal) environments. This chapter establishes the origin of these ferroan dolomite beds, documents their sequence stratigraphic significance, and draws attention to a potentially wide‐spread but rarely documented sub‐aerial exposure feature. Paludal dolomite beds associated with well‐developed palaeosols and major (Myr‐scale) disconformities probably reflect depressed Milankovitch band sea‐level oscillations that occurred during third‐order lowstands.