Acidalia Mena, Mars: A key region to test the ocean hypothesis

我们研究的主要目标是以1：20万的比例尺绘制火星北半球门萨地区的地质图。调查将主要依靠每像素100m像素尺度的热发射成像光谱仪(THEMIS)的数据，再加上HiRISE、CTX和HRSC相机的数据，以及MOLA激光高度计的地形数据。Asidalia Mensa是一个地势较高的地形，位于拟议中的火星前海洋海岸线以北。在我们新的地质图的基础上，我们建议大力检验海洋假说。现有现代成像和地形数据的质量显著提高，将使我们能够以前所未有的详细程度绘制该地区的地质图，这将大大增加我们对区域地质以及假定的海洋的存在和演化的了解。根据我们的地质图，我们将选择重点地区进行进一步的高分辨率研究。我们期待着对研究区的地质和结构有新的见解，这将使我们能够了解它的历史和演化。除了生成新的地质图外，我们还建议推导出地图单元的绝对模型年龄，破译该地区的地层，计算热惯性以估计粒度分布，并对相关地物进行形态测量。这些调查的结果将与地质图相结合，用于检验海洋假说。我们研究的一些关键科学问题包括：1.门萨高原的构造是什么，它们与周围的北部瓦斯蒂塔斯地层有什么关系？2.门萨地区和南部高地之间是否存在遗传联系？3.是否有证据表明曾经存在北极海洋？4.门萨高原是否被假定的海洋包围，或者海洋是否覆盖了研究区域？5.门萨高原有多老？它与周围地形的地层关系是什么？6.考虑到撞击坑的形态较弱，门萨高原上有多少物质被带走了？

The primary goal of our study is to geologically map the Acidalia Mensa region in the northern hemisphere of Mars at a scale of 1:200,000. The investigation will mostly rely on data of the THermal Emission Imaging Spectrometer (THEMIS) with a pixel scale of 100 m per pixel, augmented by data of the HiRISE, CTX, and HRSC cameras, as well as topography data of the MOLA laser altimeter. Acidalia Mensa is a topographically high-standing terrain north of the proposed shoreline of a putative former ocean on Mars. On the basis of our new geologic map, we propose to vigorously test the ocean hypothesis. The significantly improved quality of available modern imaging and topography data will allow us to geologically map the area in unprecedented detail, which will significantly increase our understanding of the regional geology as well as the existence and evolution of the putative ocean. On the basis of our geologic map we will select key areas for further high-resolution studies. We expect new insights into the geology and structure of the study area, which will allow us to understand its history and evolution. Besides generating a new geologic map, we propose to derive absolute model ages of the map units, decipher the stratigraphy of the area, calculate thermal inertias to estimate grain size distributions, and to perform morphometric measurements of relevant surface features. Results of these investigations, in concert with the geologic map, will be used to test the ocean hypothesis. Some key scientific questions of our study include: 1. What are the building blocks of Acidalia Mensa and what is their relationship to the surrounding Vastitas Borealis Formation? 2. Is there a genetic link between the Acidalia Mensa region and the southern highlands? 3. Is there evidence for a former north-polar ocean? 4. Was Acidalia Mensa surrounded by the putative ocean or did the ocean cover the study region? 5. How old is the Acidalia Mensa plateau and what is its stratigraphic relationship to the surrounding terrain? 6. Given the subdued morphology of impact craters, how much material has been removed from the Acidalia Mensa plateau?