Global resurfacing of Mercury 4.0-4.1 billion years ago by heavy bombardment and volcanism
Global resurfacing of Mercury 4.0-4.1 billion years ago by heavy bombardment and volcanism
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DOI：
10.1038/nature12280
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发表时间：
2013-07-04
期刊：
影响因子：
64.8
通讯作者：
Strom, Robert G.
中科院分区：
文献类型：
--
作者：
Marchi, Simone;Chapman, Clark R.;Strom, Robert G.
据估计，水星上陨石坑最多的地形大约有40亿年(Gyr)的历史(1-4年)，但这是基于仅有约45%的表面图像；即使是更老的区域也可能存在于未被观测到的部分。这些地形上直径不到100公里的陨石坑密度比月球(1，3，5)低，这归因于优先在水星上重新浮出水面。在这里，我们报道了水星整个表面上陨石坑最多的地形的全球陨石坑统计数据。应用最新的早期月球陨石坑年代学模型(6)和更新的水星动力学外推(7)，我们发现最古老的表面是在大约4.0-4.1Gyr之前的晚期强轰击(LHB)开始之后侵位的。水星的大型撞击盆地的全球记录(8)到目前为止还没有确定日期，产生了类似的地表年龄。这项协议意味着，重新浮出水面是全球性的，是由于火山作用，正如之前所说的(1，5)。这一活动在LHB的尾部结束，大约在最古老的地形在水星上安放后的3-4亿年内。这些发现表明，在这次轰炸期间，盆地规模的影响激增可能有助于持续的火山活动。
The most heavily cratered terrains on Mercury have been estimated to be about 4 billion years (Gyr) old(1-4), but this was based on images of only about 45 per cent of the surface; even older regions could have existed in the unobserved portion. These terrains have a lower density of craters less than 100 km in diameter than does the Moon(1,3,5), an observation attributed to preferential resurfacing on Mercury. Here we report global crater statistics of Mercury's most heavily cratered terrains on the entire surface. Applying a recent model for early lunar crater chronology(6) and an updated dynamical extrapolation to Mercury(7), we find that the oldest surfaces were emplaced just after the start of the Late Heavy Bombardment (LHB) about 4.0-4.1 Gyr ago. Mercury's global record of large impact basins(8), which has hitherto not been dated, yields a similar surface age. This agreement implies that resurfacing was global and was due to volcanism, as previously suggested(1,5). This activity ended during the tail of the LHB, within about 300-400 million years after the emplacement of the oldest terrains on Mercury. These findings suggest that persistent volcanism could have been aided by the surge of basin-scale impacts during this bombardment.