Revisão de formas erosivas relacionadas à ação do gelo no Paleozoico superior da Bacia do Paraná: origem e implicações paleogeográficas
Revisão de formas erosivas relacionadas à ação do gelo no Paleozoico superior da Bacia do Paraná: origem e implicações paleogeográficas
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巴拉那州巴西亚高级古生代的侵蚀关系形式修订：古地理学的起源与暗示
DOI：
10.1590/2317-4889201620160050
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发表时间：
2016
影响因子：
1.4
通讯作者：
A. B. França
中科院分区：
文献类型：
--
作者：
Eduardo Rosa;F. Vesely;A. B. França
巴拉那盆地晚古生代冰期记录为伊塔拉雷群的冰川沉积、变形特征和与冰有关的侵蚀地貌。侵蚀地貌常被用来建立古地理模型，以描述冰块的位置和古冰流的方向。本文提供了一个审查的文献和新的数据微观到中尺度的冰相关，巴拉那盆地的侵蚀地貌。所研究的地貌可根据其起源方式分为四大类。刚性基底上的冰下地貌发生在前寒武纪基底或巴拉那盆地的较老单元上。它们包括流线型地貌和由前进的冰川下的磨损和/或采摘形成的条纹路面。软床上的冰下地貌是由松散沉积物被冰川覆盖时的侵蚀和变形所产生的层内表面。冰龙骨冲刷痕迹是由自由漂浮的冰块冲刷下伏沉积物而形成的软沉积物条纹状/沟槽状地貌。条纹碎屑铺路层是指含有排列碎屑的层位，这些碎屑是由于冰川在松散沉积物上的推进而在冰下磨损的。只有那些冰川下形成的侵蚀地貌才能作为可靠的古冰流指标。基于这些数据，巴拉那盆地晚古生代冰期的古地理适合于一个模型，该模型由位于盆地周围的地形控制的冰扩展中心而不是单个大陆冰盖的几个冰川裂片组成。
The Late Paleozoic Ice Age is recorded in the Parana Basin as glacial deposits, deformational features and ice-related erosional landforms of the Itarare 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 Parana 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 Parana 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 Parana 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.