Department of Geophysics and Center for Space Resources, Colorado School of Mines, Golden, CO 80401, USA.
Science. 2013 Feb 8;339(6120):675-8. doi: 10.1126/science.1231753. Epub 2012 Dec 5.
The earliest history of the Moon is poorly preserved in the surface geologic record due to the high flux of impactors, but aspects of that history may be preserved in subsurface structures. Application of gravity gradiometry to observations by the Gravity Recovery and Interior Laboratory (GRAIL) mission results in the identification of a population of linear gravity anomalies with lengths of hundreds of kilometers. Inversion of the gravity anomalies indicates elongated positive-density anomalies that are interpreted to be ancient vertical tabular intrusions or dikes formed by magmatism in combination with extension of the lithosphere. Crosscutting relationships support a pre-Nectarian to Nectarian age, preceding the end of the heavy bombardment of the Moon. The distribution, orientation, and dimensions of the intrusions indicate a globally isotropic extensional stress state arising from an increase in the Moon's radius by 0.6 to 4.9 kilometers early in lunar history, consistent with predictions of thermal models.
由于撞击物通量高，月球的早期历史在地表地质记录中保存不佳，但该历史的某些方面可能保存在地下结构中。对重力恢复和内部实验室（GRAIL）任务观测结果应用重力梯度测量，确定了具有数百公里长度的线性重力异常群。对重力异常的反演表明，存在拉长的正密度异常，这些异常被解释为古老的垂直板状侵入体或岩脉，它们是由岩浆作用与岩石圈伸展相结合形成的。切割关系支持前 Nectarian 到 Nectarian 年龄，早于月球遭受重轰炸的结束。侵入体的分布、方位和尺寸表明，在月球历史早期，月球半径增加了 0.6 到 4.9 公里，导致出现了一种全球各向同性的拉伸应力状态，这与热模型的预测一致。
