Just as glaciers worldwide left a record of past advances and retreats that shifted latitudinally in response to oscillating Quaternary climate changes, so too have cold-climate conditions and permafrost left topographic and sedimentary signatures in former periglacial environments. This review documents widespread occurrence of past permafrost and intense frost action that led to rock fracturing, regolith production, and regolith-mantled slopes in the mid-Atlantic region of the United States during late Pleistocene cold-climate conditions. Strong signatures of thermal contraction cracking and brecciation from frost cracking exist where rocks and sediments are most frost susceptible, as with fissile shales. On sandstone hillslopes, frost weathering produced boulder-rich sediment that episodically flowed slowly down-slope during permafrost thaw, resulting in solifluction lobes and terraces in which colluvium moved cumulatively at least a kilometer. Radiocarbon dating, optically stimulated luminescence age control, and cosmogenic isotope studies constrain some periglacial features to the Last Glacial Maximum but also indicate longer residence times of regolith. ▪ Former permafrost and areas of intensive frost cracking extended over much of the mid-Atlantic region of the eastern United States during late Pleistocene cold glacial periods. ▪ Cold-climate conditions and permafrost left long-lasting topographic and sedimentary records with limited post-depositional erosion in the formerly periglacial mid-Atlantic region. ▪ Prominent relict periglacial landforms include polygon networks and frost wedges that are the result of thermal contraction cracking and brecciated rock formed by segregated ice and frost cracking. ▪ Widespread solifluction landforms are a topographic signature of freezing, thawing, and mass movement of mobile regolith produced by frost cracking, and some were active during the Last Glacial Maximum.

中文翻译：

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美国东部大西洋中部地区更新世冰缘过程和地貌

正如世界各地的冰川留下了过去的进退记录，这些记录随着第四纪气候变化而发生纬度变化一样，寒冷的气候条件和永久冻土也在以前的冰缘环境中留下了地形和沉积特征。这篇综述记录了美国大西洋中部地区在更新世晚期寒冷气候条件下，过去永久冻土的广泛发生和强烈的霜冻作用，导致岩石破裂、风化层生成和风化层覆盖的斜坡。在岩石和沉积物最易受霜冻影响的地方，如裂变页岩，存在强烈的热收缩破裂和霜冻角砾化特征。在砂岩山坡上，霜冻风化产生了富含巨石的沉积物，在永久冻土融化期间，这些沉积物偶尔会缓慢地向下坡流动，形成溶流瓣和阶地，其中崩积层累计移动至少一公里。放射性碳测年、光激发光年龄控制和宇宙成因同位素研究将一些冰缘特征限制在末次盛冰期，但也表明风化层的停留时间更长。 ▪ 在晚更新世冷冰期期间，前永久冻土层和密集冻裂区域延伸至美国东部大西洋中部地区的大部分地区。 ▪ 寒冷的气候条件和永久冻土在以前的大西洋中部冰缘地区留下了长期的地形和沉积记录，且沉积后侵蚀有限。 ▪ 突出的冰缘遗迹地貌包括多边形网络和霜楔，它们是热收缩开裂的结果，以及由分离的冰和霜开裂形成的角砾岩。 ▪ 广泛分布的溶流地貌是由冻裂产生的移动风化层冻结、融化和大规模移动的地形特征，其中一些在末次盛冰期期间很活跃。