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阿拉斯加北部石炭系Lisburne群在挤压和拉伸构造背景下变形成为各种绘图比例尺的构造,这为在厚层碳酸盐岩单元中观察裂缝的形成、分布及其特性提供了天然实验室。北斜坡地下和附近的布鲁克斯山区东北部冲断褶皱带Lisburne群以两组裂缝为主。北北西向区域张裂缝可能形成于布鲁克斯山区东北部的冲断褶皱带前缘。在北斜坡地下,该组裂缝叠加在早期伸展变形形成的北东东向裂缝之上;相反,在冲断褶皱带,北北西向裂缝之上叠加的是与后期收缩变形作用有关的较年轻的北东东向裂缝。岩性是两组裂缝密度的主要控制因素。在轻度变形的Lisburne群碳酸盐岩中,相比较而言,粒状灰岩中裂缝发育最少,白云质泥灰岩中裂缝发育最多。但是,在发生过冲断褶皱作用的Lisburne碳酸盐岩中,构造位置对整个裂缝特征和密度起着更重要的作用。在对Lisburne群和其它可能由裂缝控制或由裂缝增强了其储集性的碳酸盐岩的勘探中,在研制裂缝形成的预测模型时,既需要考虑碳酸盐岩的岩性,也需要考虑构造位置。裂缝的特征和密度在一个给定区域内,有时甚至是在一个单独构造上都可以发生突然的变化。在变形作用较小的层段中,裂缝作用偏弱的岩石类型在变形作用增强时,裂缝密度将经历最大程度的相对增加。
The Carboniferous Lisburne Group in the northern part of Alaska deforms under the compressive and tensile tectonic setting into a variety of plot scale structures, providing a natural laboratory for observing the formation, distribution and characterization of fractures in thick carbonate units. The Lisburne Group, a thrust fold zone in the northeast of the North Brooks and adjacent to the North Slope, is dominated by two sets of fractures. North-west-west Zhangjiakou fractures may form in the front of the thrust fold belt in the northeast of the Brooks. On the northern slopes, this group of fractures superimposed on the NE-trending fractures formed by early extensional deformation. On the contrary, superimposed on the thrust-fold belt and north-northwest-trending fractures is the younger North east-east crack. Lithology is the main controlling factor for the fracture density in both groups. In the slightly deformed Lisburne group carbonates, the fractures are the least in the grained limestone and the most in the dolomitic marl. However, in Lisburne carbonates where thrusting and folding occurred, the tectonic location played a more important role in overall fracture characteristics and density. In the exploration of the Lisburne group and other carbonate rocks that may be controlled by fractures or enhanced by fractures, the prediction models for fracture formation need to consider not only the lithology of carbonate rocks but also Consider the construction location. Crack features and densities can vary abruptly in a given area, sometimes even on a single structure. In the deformation-less intervals, the fracture types will experience the greatest relative increase in deformation when the type of rock with weak fracture function increases.