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首页> 外文期刊>Brazilian Journal of Geology >A review on late Paleozoic ice-related erosional landforms in the Paran?? Basin: origin and paleogeographical implications
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A review on late Paleozoic ice-related erosional landforms in the Paran?? Basin: origin and paleogeographical implications

机译：波兰晚古生代与冰有关的侵蚀地貌综述？盆地：起源和古地理意义

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The Late Paleozoic Ice Age is recorded in the Paran?? Basin as glacial deposits, deformational features and ice-related erosional landforms of the Itarar?? Group. Erosional landforms are often employed to build paleogeographic models that depict the location of ice masses and paleo ice-flow directions. This paper provides a review of the literature and new data on micro- to meso-scale ice-related, erosional landforms of the Paran?? Basin. Examined landforms can be placed into four broad categories based on their mode of origin. Subglacial landforms on rigid substrates occur on the Precambrian basement or on older units in the Paran?? Basin. They include streamlined landforms and striated pavements formed by abrasion and/or plucking beneath advancing glaciers. Subglacial landforms on soft beds are intraformational surfaces generated by erosion and deformation of unconsolidated deposits when overridden by glaciers. Ice-keel scour marks are soft-sediment striated/grooved landforms developed by the scouring of free-floating ice masses on underlying sediments. Striated clast pavements are horizons containing aligned clasts that are abraded subglacially due to the advance of glaciers on unconsolidated deposits. Only those erosional landforms formed subglacially can be used as reliable paleo ice-flow indicators. Based on these data, the paleogeography of the Paran?? Basin during the Late Paleozoic Ice Age fits into a model of several glacial lobes derived from topographically-controlled ice spreading centers located around the basin instead of a single continental ice sheet.
机译：帕兰族记录了晚古生代冰河时代？作为伊塔拉尔冰川沉积，变形特征和与冰有关的侵蚀地貌的盆地？组。经常使用侵蚀地貌来构建古地理模型，以描述冰块的位置和古冰流向。本文提供了有关Paran ??的中小型与冰有关的侵蚀性地貌的文献资料和新数据的综述。盆地。根据地貌的来源，可以将其分为四大类。刚性基底上的冰下地形发生在前寒武纪的地下室或Paran ??的较旧单元中？盆地。它们包括通过磨蚀和/或拔除前进的冰川下方形成的流线型地形和横纹的人行道。软床上的冰下地貌是由于冰川覆盖而导致的未固结沉积物的侵蚀和变形而形成的构造内表面。冰龙骨冲刷痕迹是通过在下伏沉积物上冲刷自由漂浮的冰块而形成的软沉积横纹/开槽地形。条纹状碎石路面是包含对齐碎屑的地层，这些碎屑由于冰川在未固结沉积物上的推进而在冰川下被磨损。只有那些在冰期以下形成的侵蚀地貌才可以用作可靠的古冰流指标。根据这些数据，波兰的古地理环境？晚古生代冰期的盆地适合于几个冰川裂片的模型，这些冰川裂片是由位于盆地周围而不是单个大陆冰原的地形控制冰扩散中心衍生的。

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