Due to its size and observable record of ancient rock, Mars is key to understanding crustal formation on planetary bodies, including Venus and Earth, which may have derived their first stable crust from mantle-overturn melting. Recent evidence that ancient martian crust contains an evolved component supports inferences of a pervasive, buried feldspathic component to the crust. With data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), we searched for feldspathic lithologies in pre-Noachian (older than ca. 4.1 Ga) crustal blocks uplifted by the Hellas basin-forming impact. We present evidence for ancient feldspathic rocks exposed across an ~2200 × 600 km area north of Hellas. Given their pre-Noachian age and stratigraphic position directly above putative mantle material, it is possible that these outcrops represent martian primary crust. Our discovery supports the hypothesis that there exists a pervasive, subsurface feldspathic component to the martian crust—a hypothesis that has, until now, been supported only by inferences from geodynamic data and small-scale observations.

中文翻译：

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在火星北海拉斯边缘发现广泛而古老的长石地壳：对初级地壳形成的可能影响

由于其大小和可观测到的古代岩石记录，火星是了解行星体地壳形成的关键，包括金星和地球，它们的第一个稳定地壳可能来自地幔翻转融化。最近的证据表明，古代火星地壳含有一种进化成分，这支持了对地壳普遍存在的、埋藏的长石成分的推断。利用来自火星紧凑型侦察成像光谱仪 (CRISM) 的数据，我们在由 Hellas 盆地形成影响抬升的前诺亚纪（早于约 4.1 Ga）地壳块中寻找长石岩性。我们提供了在希腊以北约 2200 × 600 公里区域内暴露的古代长石岩的证据。鉴于它们的前诺亚纪时代和地层位置直接位于假定的地幔物质之上，这些露头可能代表火星的原始地壳。我们的发现支持了火星地壳存在普遍的地下长石成分的假设——直到现在，这一假设仅得到地球动力学数据和小规模观测的推论的支持。