The Gulf of Papua inner mid‐shelf clinothem and lowstand deposits in Pandora Trough record sediment source and routing through the last sea‐level cycle on 20 kyr cycles. Clay mineralogy tracked dispersal of sediment from the two types of rivers (wide versus narrow floodplains) to constrain the contributions of river systems to the Gulf of Papua clinothem and Pandora Trough deposits. Fly River sediment has higher illite:smectite than clays from the small mountainous rivers (Bamu, Turama, Kikori and Purari rivers) that drain regions with more limestones. X‐ray diffraction shows high illite:smectite proximal to the Fly River delta that decrease towards the north‐east. Downcore mineralogy of inner mid‐shelf cores reveals that the largest shifts in illite:smectite correspond to changes in sediment units. The relict clinothem emplaced on the Gulf of Papua shelf during Marine Isotope Stage 3 has lower illite:smectite than the Holocene clinothem that has been building since 2 ka and the Marine Isotope Stage 5a relict clinothem. In the inner mid‐shelf, downcore decreases in illite:smectite during Marine Isotope Stage 3 suggest that this region received less clay from the Fly River and more contributions from small mountainous rivers. During Marine Isotope Stage 3, the exposed physiography and narrower shelf in this region may have deflected Fly River sediment more south‐eastward, where it bypassed the inner shelf via the Kiwai, Purutu and Umuda valleys and was deposited in the Pandora Trough. The Fly River may have been more susceptible to valley incision because of its limited shelf accommodation and higher ratio of water to sediment discharge. Such bypass of the inner mid‐shelf by Fly River sediment during the Marine Isotope Stage 2 sea‐level lowstand is recorded in Pandora Trough deposits with high illite:smectite ratios. Inner mid‐shelf clinothems with compositional shifts on the order of 20 kyr may be influenced by shelf physiography, accommodation and the variable incision by small and large rivers.

中文翻译：

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巴布亚湾架子和潘多拉海槽沉积物的粘土矿物学限制了最后一个海平面周期内的沉积物路线

潘多拉海槽中的巴布亚湾中陆架内部气候低潮和低水位沉积物记录了沉积物的来源，并记录了过去20个海平面的海平面旋回。粘土矿物学跟踪了两种类型的河流（宽泛河与窄洪泛河）的沉积物扩散，以限制河流系统对巴布亚clinothem湾和潘多拉海槽沉积物的贡献。飞河沉积物中的伊利石：蒙脱石比来自山区河流（巴木河，图拉马河，基科里河和普拉里河）的黏土要多，石灰岩会流失更多的石灰石。X射线衍射显示出高伊利石：蒙蒙石，靠近飞河三角洲，向东北方向减少。中间中层岩心的下层矿物学表明，伊利石：蒙脱石的最大位移与沉积物单元的变化相对应。在海洋同位素第3阶段期间放置在巴布亚湾架子上的遗留气候斜纹岩的伊利石：蒙脱石比自2 ka和海洋同位素第5a阶段遗留斜纹岩斜石以来的全新世clinothem低。在中陆架内部，在海洋同位素第3阶段，伊利石：蒙脱石的下芯减少，表明该地区从Fly河得到的粘土较少，而从山区河流得到的贡献更大。在海洋同位素第3阶段，该地区裸露的地貌和较窄的陆架可能使Fly River沉积物向东南偏斜，在那里它通过Kiwai，Purutu和Umuda谷绕过内陆架，并沉积在潘多拉海槽中。飞河由于其有限的陆架空间和较高的水与泥沙排放比而可能更容易受到山谷切口的影响。在海洋同位素第2阶段海平面低位期间，飞河沉积物绕过了内部中层架，这在伊利石：蒙脱石比率高的潘多拉槽沉积物中记录了下来。架子上的地貌，适应性以及大小河流的可变切口可能会影响内部中层斜向倾斜，其成分变化约为20 kyr。