Chryse Planitia, Mars: Topographic configuration, outflow channel continuity and sequence, and tests for hypothesized ancient bodies of water using Mars Orbiter Laser Altimeter (MOLA) data
Chryse Planitia, Mars: Topographic configuration, outflow channel continuity and sequence, and tests for hypothesized ancient bodies of water using Mars Orbiter Laser Altimeter (MOLA) data
复制标题
Chryse Planitia，火星：地形构造、流出通道连续性和序列，以及使用火星轨道飞行器激光高度计 (MOLA) 数据对假设的古代水体进行的测试
DOI：
10.1029/2000je001257
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发表时间：
2001
影响因子：
--
通讯作者：
J. Head
中科院分区：
文献类型：
--
作者：
M. Ivanov;J. Head
火星上许多最大和最突出的流出通道都进入了克莱斯·普兰蒂亚。火星之前的全球勘测者地形数据显示，克莱斯是一个直径近2000公里的封闭凹陷。新的火星轨道激光高度计(MOLA)数据揭示如下：(1)克莱斯并不是一个局部封闭的盆地，而是向北极盆地开放。(2)六条最大的、主要是西方古老的海峡(开塞、玛雅、西穆德、提乌、阿瑞斯和莫尔斯)高度独特的地貌消失在北部低地，平均海拔都在∼3742(SD=153米)的低于−170米的范围内，横向距离超过2,500公里。(3)每个航道独特地貌消失的高程都落在2号触点的∼190m以内，这是帕克等人绘制的边界。[1993]并被解释为代表一条古老的海岸线，并且接触点2和环状-克莱斯海峡终点的平均高程值彼此落在18米以内。相比之下，从极乐世界进入乌托邦平原的七条亚马逊时代晚期河道的末端分布在1500米的垂直范围内。(4)在进入北极盆地250-450公里的距离内，可以观察到一些流出河道继续存在的地形证据，但形态平淡且明显不同。(5)这种不太独特的地形的性质及其横切关系表明，Simud和Tiu很可能代表最年轻的活动(特别是横切Ares Valles)。(6)航道形态的显著变化与在基准面(水下/海底边界)遇到的快速能量损失和向浅海环境的侵位相一致。航道特征，缺乏明显的三角洲或叶，以及持续低沉的航道形态，表明有可能出现高密度流和浑浊流。对个别渠道活动数量的估计是多种多样的。CARR[1996]的最小流量估计表明，需要46次这样的事件才能将盆地填满到接触2的水平，因此，水道可能已经排入现有的固定水体。贝克等人的数量估计。[1991]假设单个单独的事件可能已经将盆地填满到接触2的水平，因此在事件之间需要大量的水损失，并且在后续事件期间重新填充到基本上相同的水平。在这两个终端成员的情况下，这些观察结果与西伯利亚-亚马孙早期北部低地存在的大片死水是一致的。
Many of the largest and most prominent outflow channels on Mars debouch into Chryse Planitia. Pre-Mars Global Surveyor topographic data show Chryse to be a closed depression almost 2000 km in diameter. New Mars Orbiter Laser Altimeter (MOLA) data reveal the following: (1) Chryse is not a locally closed basin but instead opens into the North Polar basin. (2) The highly distinctive morphology of the six largest predominantly Hesperian-aged channels (Kasei, Maja, Simud, Tiu, Ares, and Mawrth) disappears into the northern lowlands at average elevations that all occur within less than ∼170 m of a mean elevation of −3742 (SD = 153 m), over a lateral distance in excess of 2500 km. (3) The elevations where the distinctive morphology of each channel disappears all fall within ∼190 m of Contact 2, a boundary mapped by Parker et al. [1993] and interpreted to represent an ancient shoreline, and the mean elevation values of Contact 2 and circum-Chryse channel termini fall within 18 m of each other. In contrast, the termini of seven later Amazonian-aged channels emerging from Elysium into Utopia Planitia are spread over a vertical range of >1500 m. (4) Topographic evidence of the continuation of some of the outflow channels can be observed for distances of 250–450 km into the North Polar basin, but the morphology is subdued and distinctly different. (5) The nature of this less distinctive topography and its crosscutting relationships show that Simud and Tiu are likely to represent the youngest activity (specifically crosscutting Ares Valles). (6) The distinctive change in channel morphology is consistent with rapid loss of energy encountered at base level (subaerial/submarine boundary) and emplacement into a shallow submarine environment. Channel characteristics, lack of distinctive deltas or lobes, and continuation of subdued channel morphology suggest hyperpychnal flow and the possibility of density/turbidity currents. Estimates of the volumes of individual channel events are wide-ranging. The minimum volume estimates of Carr [1996] suggest that 46 such events would be required to fill the basin to the level of Contact 2 and thus that the channels may have emptied into an existing standing body of water. Volume estimates of Baker et al. [1991] assume that single individual events may have filled the basin to the level of Contact 2, thus requiring significant water loss between events and refilling during subsequent events to essentially the same level. In both end-member cases these observations are consistent with the presence of large standing bodies of water in the northern lowlands in Hesperian-Early Amazonian times.