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首页> 外文期刊>Journal of geodynamics >Glaciation, erosion, and landscape evolution of Iceland
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Glaciation, erosion, and landscape evolution of Iceland

机译：冰岛的冰川，侵蚀和景观演变

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摘要

Stratigraphic and sedimentological studies indicate that Iceland has experienced over 20 glaciations during the last 4-5 Myr, in reasonable agreement with the number of glaciations reconstructed from the partial deriv~(18)O record in deep-sea sediment. The pattern of glacial erosion was to a large part controlled by constructive volcanic processes resulting in increased topographic relief after 2.5 Myr. Between 2.5 and 0.5 Ma valleys up to 400m deep were excavated into the Tertiary basalts of eastern and south Iceland with an average erosion rate of 10-20cm ka~(-1). During the last 0.5 million years rates of erosion increased to 50-175cmka~(-1), with an additional 200 to over 1000 m of valley excavation. Previous estimates of the rate of landscape erosion during the Holocene vary widely, from 5 to 70,000 cm ka~(-1). We present new studies that define the rates of landscape denudation during the major part of the Holocene (the last 10,200 years): one based on the Iceland shelf sediment record, the other from the sediment record in the glacier-fed lake, Hvitarvatn. Both studies indicate average Holocene erosion rates of about 5 cm ka~(-1) similar to our erosion rate estimate for 4-5 Ma old strata that has not been subjected to regional glaciation.
机译：地层学和沉积学研究表明，冰岛在最近的4-5 Myr期间经历了20多次冰期，这与根据深海沉积物中的偏导〜（18）O记录重建的冰川数合理地吻合。冰川侵蚀的模式在很大程度上受建设性火山作用控制，导致2.5 Myr后地形起伏增加。在冰岛东部和南部的第三纪玄武岩中开挖了2.5至0.5 Ma的深达400m的山谷，平均侵蚀速率为10-20cm ka〜（-1）。在过去的50万年中，侵蚀速率增加到50-175cmka〜（-1），另外还有200至1000 m以上的山谷开挖。全新世期间景观侵蚀速率的先前估计值差异很大，从5到70,000 cm ka〜（-1）。我们提出了新的研究，这些研究定义了全新世大部分时间（最近10,200年）的景观剥蚀率：一项基于冰岛的陆架沉积物记录，另一项基于冰川喂养的湖泊Hvitarvatn中的沉积物记录。两项研究均表明，全新世平均侵蚀速率约为5 cm ka〜（-1），与我们对尚未经历区域冰川作用的4-5 Ma老地层的侵蚀速率估算值相似。

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