Geology of a region connecting the lower and higher levels of the Vastitas Borealis Formation boundary: Assessment of the Hesperian hydrologic activity and long-wavelength topographic changes on Mars

我们研究的主要目标是详细调查西部不连续性的Vastitas Borealis形成（VBF）之间的Deuteronilus和Nilocaltis部分，乌托邦平原和Acidalia平原之间的区域，连接两个不同的水平的外边缘的Vastitas Borealis形成（VBF）的北方平原。研究结果对于评价VBF的地形形态和侵位方式具有重要意义。VBF覆盖了北方低地的大部分地区，并一直被解释为过去北方海洋的沉积残留物。VBF边缘的形态设置和地形配置特别令人感兴趣，因为它们与陆地海岸接触有相似之处。这项研究的结果可能有助于增加我们对火星上假定的北方海洋的范围、时间和持续时间的了解。我们的研究的目的是解决以下科学问题密切相关的火星海洋假说的各个方面：在这一地区的地形和形态设置提供证据表明，VBF由一系列连续的单位，建议多集的安置？它的高度是在高低层之间不断变化的吗？或者，它是否显示了差距内某个地方的区域尺度坡度突变？是否有证据表明，接触的高段和低段是断开的，代表独立的特征？它们是否与将VBF解释为前海洋或多个海规模水体的升华残留物相一致？沿着VBF边界选定区域的陨石坑计数结果如何约束VBF侵位的时间间隔？

The primary goal of our study is to investigate in detail the western discontinuity of the Vastitas Borealis Formation (VBF) contact between its Deuteronilus and Nilosyrtis segments, a region between Utopia Planitia and Acidalia Planitia that connects the two distinct levels of the outer edge of the Vastitas Borealis Formation (VBF) within the northern plains. Results of this research are crucially important for the assessment of the topographic configuration and mode of emplacement of the VBF. The VBF covers vast parts of the northern lowlands and has been continuously interpreted to be a depositional residue of a past northern ocean. The morphologic setting and topographic configuration of the VBF edges are of particular interest as they share similarities with terrestrial coastal contacts. The results of this study could help to increase our knowledge about the extent, timing and duration of the postulated northern ocean on Mars. Our study is aimed to address the following scientific questions closely related to various aspects of the Martian ocean hypothesis: Does the topographic and morphologic setting in this region provide evidence that the VBF consists of a series of sequential units suggesting multiple episodes of its emplacement? Is its elevation changed continuously between the lower and the higher levels? Or, does it show a regional-scale break of slope somewhere within the gap? Is there evidence suggesting that the higher and lower segments of the contact are disconnected and represent independent features? Are they consistent with the interpretation of the VBF as a sublimation residue of a former ocean or of multiple sea-scale standing bodies of water?How do the results of crater counts in selected areas along the VBF boundary constrain the time interval of the VBF emplacement?