英国开放大学Turner Stuart M. R.课题组在最新研究中，报道了高地遗迹记录的诺亚火星上的二分后退和水蚀变。该项研究成果发表在2025年1月20日出版的《自然—地球科学》上。

据悉，Mawrth Vallis地区是一个高原，位于火星半球二分边界的高地一侧。具有200米厚的层状硅酸盐地层演替，表明在4.1Ga和3.7在诺亚时期。此外，在mawth山谷北部和西部的低地，已经确定了公里规模的孤立土丘的需求。

课题组人员通过地貌和光谱分析表明，这些土丘是在诺亚亚高原撤退过程中形成的侵蚀残余物。因此，在这个地区，标志着两分法表面表达的悬崖，可能已经向东南偏南后退了数百公里。土丘的横向和地层地球化学变化表明，该地区在地表和地下环境中发生了广泛的、多相的原位水蚀变。

丘序下部是一个富含辉石岩的单元，它代表了区域层状硅酸盐层序下方未改变的物质，并被一个薄盖单元不整合地覆盖，标志着大规模区域水活动的结束。这些土丘包含了该地区诺亚时期，水环境的开始、演变和停止的地层记录，详细描述了火星最适宜居住时的环境和气候。

附：英文原文

Title: Dichotomy retreat and aqueous alteration on Noachian Mars recorded in highland remnants

Author: McNeil, Joseph D., Fawdon, Peter, Balme, Matthew R., Coe, Angela L., Cuadros, Javier, Turner, Stuart M. R.

Issue&Volume: 2025-01-20

Abstract: The Mawrth Vallis region is a plateau situated on the highland side of Mars’ hemispheric dichotomy boundary. It has a >200-m-thick phyllosilicate-bearing stratigraphic succession that indicates extensive aqueous alteration between 4.1Ga and 3.7Ga, during the Noachian Period. In addition, thousands of kilometre-scale isolated mounds in the lowlands north and west of Mawrth Vallis have been identified. Here we use geomorphological and spectroscopic analyses to show that the mounds are erosional remnants that formed through retreat of the highland plateau in the Noachian. Consequently, the escarpment that marks the surface expression of the dichotomy must have receded south-southeast by hundreds of kilometres in this area. Lateral and stratigraphic geochemical variation in the mounds show that widespread, multiphase aqueous alteration occurred in situ across this region in surface and subsurface environments. The mound succession is underlain by a pyroxene-rich unit that represents unaltered material below the regional phyllosilicate-bearing sequence and is unconformably overlain by a thin capping unit that marks the end of large-scale regional aqueous activity. Thus, the mounds contain a stratigraphic record of the onset, evolution and cessation of Noachian aqueous conditions in this region, detailing the environment and climate of Mars at its most habitable.

DOI: 10.1038/s41561-024-01634-8

Source: https://www.nature.com/articles/s41561-024-01634-8