Propagation of long fractures in the Ronne Ice Shelf, Antarctica, investigated using a numerical model of fracture propagation
Propagation of long fractures in the Ronne Ice Shelf, Antarctica, investigated using a numerical model of fracture propagation
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DOI：
10.3189/002214310792447743
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发表时间：
2010-01-01
影响因子：
3.4
通讯作者：
Cruikshank, Kenneth
中科院分区：
文献类型：
--
作者：
Hulbe, Christina L.;LeDoux, Christine;Cruikshank, Kenneth
南极洲伦讷冰架前部附近的长裂缝被观察到开始为裂缝，沿着供给冰架的出口流的横向边界。这些裂缝最终成为扁平冰山崩裂的沿着面。裂缝横向传播，因为他们平流通过货架，与方向，可以解释的冰川应力场。断裂长度仍然限制在大部分的平流路径，裂纹尖端逮捕的位置观察到与结构边界相吻合，如相邻出口冰川冰之间的缝合带。地质力学原理和数值模型表明，在没有这些缝合带的情况下，裂纹尖端不太可能停在这些位置。我们的结论是，横向不均匀性在冰断裂力学中起着重要的作用，通过大部分的冰架。只有在大陆架前缘附近，这些局部结构效应才被克服，从而形成了形成板状冰山所需的大裂缝。
Long rifts near the front of the Ronne Ice Shelf, Antarctica, are observed to begin as fractures along the lateral boundaries of outlet streams feeding the shelf. These flaws eventually become the planes along which tabular icebergs calve. The fractures propagate laterally as they advect through the shelf, with orientations that can be explained by the glaciological stress field. Fracture length remains constrained over much of the advective path, and locations of crack tip arrest are observed to coincide with structural boundaries, such as suture zones between ice from adjacent outlet glaciers. Geomechanical principles and numerical models demonstrate that in the absence of these suture zones crack tips are unlikely to arrest in these locations. We conclude that lateral inhomogeneity in the ice plays an important role in fracture mechanics through most of the ice shelf. Only near the shelf front are these local structural effects overcome such that the large rifts required for tabular iceberg production develop.