Investigation of the process sedimentology of mouth bar deposition demonstrates a link to the seasonality associated with abrupt climate warming events during the early Eocene. While a relationship between fluvial sedimentology and climate events has been established previously, such documentation within mouth bar deposits is missing. Deltaic mouth bars of the Douglas Creek Member of the Green River Formation in the Uinta Basin record a fluvial–lacustrine response to abrupt warming events associated with the Early Eocene Climatic Optimum. This study ties the observed sedimentology of these mouth bars and their deposition via hyperpycnal currents to these climatic events. Detailed measured sections and analysis of stratigraphic architecture of outcrops in the eastern Uinta Basin document the sedimentology and stratigraphy of delta mouth bar complexes. Internal structures include climbing ripple cross-lamination, convolute bedding, and those associated with transitional to upper-flow regime bedforms such as planar laminations with normal grading and convex-upward stratifications. The dominance of upper-flow regime bedforms as well as interpreted long run out distances suggests that density currents deposited mouth bars tens of kilometres from the shoreline under Froude supercritical flow conditions. The highly seasonal climate regime of the early Eocene, capable of producing high-sediment yield flooding events, likely provided the mechanism for hyperpycnal current formation within a relatively freshwater lake and controlled the timing of mouth bar deposition. Discrete lacustrine carbonate-dominated packages separate periods of episodic fluvial discharge, recording reduced fluvial deposition between warming events. The established link between the occurrence of upper-flow regime bedforms and the timing of climate warming events suggests that these climate conditions may be important for their formation and preservation. The study has implications for expanding existing mouth bar depositional models to include climatically controlled upper-flow regime bedforms.

中文翻译：

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受气候影响的高峡口条的地层构造

对口坝沉积过程的沉积学研究表明，与始新世初期突然的气候变暖事件有关的季节性相关。尽管先前已经建立了河流沉积学与气候事件之间的关系，但缺乏在口状沉积物中的此类记录。Uinta盆地的Green River组的Douglas Creek成员的三角洲口岸记录了河流-湖相对与早期始新世最佳气候相关的突然变暖事件的响应。这项研究将观察到的这些口岸的沉积学及其通过高温流的沉积与这些气候事件联系起来。Uinta盆地东部露头的详细测量剖面和地层学结构分析记录了三角洲三角洲河口坝群的沉积学和地层学。内部结构包括爬升波纹交叉层合，回旋层理以及与过渡到上流状态层状相关的层状结构，例如具有正常坡度和凸向上分层的平面层合。上流态床状体的优势以及解释的长跳动距离表明，在弗洛德超临界流条件下，密度流沉积在距海岸线数十公里处的口坝上。始新世初期的高度季节性气候体制，能够产生高沉积物的洪水泛滥事件，可能提供了在相对淡水湖中形成高次电流的机制，并控制了口岸沉积的时间。离散的湖相碳酸盐为主的包裹将周期性的河床排泄期分开，记录了变暖事件之间河床沉积的减少。上流态床形的发生与气候变暖事件发生的时间之间已建立的联系表明，这些气候条件对于它们的形成和保存可能是重要的。该研究对扩展现有的口坝沉积模型包括气候控制的上流态床形具有重要意义。记录变暖事件之间河流沉积的减少。上流态床形的发生与气候变暖事件发生的时间之间已建立的联系表明，这些气候条件对于它们的形成和保存可能是重要的。该研究对扩展现有的口坝沉积模型包括气候控制的上流态床形具有重要意义。记录变暖事件之间河流沉积的减少。上流态床形的发生与气候变暖事件发生的时间之间已建立的联系表明，这些气候条件对于它们的形成和保存可能是重要的。该研究对扩展现有的口坝沉积模型包括气候控制的上流态床形具有重要意义。