Ages and stratigraphy of lunar mare basalts: A synthesis
Ages and stratigraphy of lunar mare basalts: A synthesis
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DOI：
10.1130/2011.2477(01
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发表时间：
2011-01-01
期刊：
影响因子：
--
通讯作者：
Neukum, G.
中科院分区：
文献类型：
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作者：
Hiesinger, H.;Head, J. W., III;Neukum, G.
月球火山活动的年表是基于阿波罗和月球着陆点样本的放射性年龄、区域地层关系、火山口退化和大小频率分布数据，这些数据主要是在阿波罗计划结束之前确定的。月海玄武岩年龄的准确估计是必要的，以限制月球火山活动的持续时间和流量，以及月海玄武岩的岩石成因及其与月球热演化的关系。在这里，我们报告的年龄来自陨石坑的大小频率分布测量暴露月海玄武岩单位在月球近半球。陨石坑的大小频率分布测量提供了一个统计上可靠和准确的方法来推导月球和其他行星表面未采样区域的绝对模型年龄。本文总结和综合的结果，从我们的陨石坑计数的努力超过10年。我们已经在Oceanus Procellarum，Imperium，Serenitatis，Tranquillitatis，Humboldtianum，Australe，Humorum，Nubium，Cognitum，Nectaris，Frigoris以及许多较小的事件，如撞击坑和窦和湖泊地区的玄武岩。我们的研究表明：（1）在所调查的盆地中，月球火山活动活跃了近30亿年，从3.9 - 4.0 b.y.开始，前和停止在类似于1.2 b.y.（2）大部分玄武岩喷发于晚寒武纪，约3.6 - 3.8亿年;以前，（3）埃拉托塞尼亚时期侵位的玄武岩明显较少，（4）仅在Oceanus Procellarum的有限区域发现了可能属于哥白尼时代的玄武岩。我们的研究结果证实并扩展了月海玄武岩火山作用年龄的一般分布，并进一步强调了在东部和南部近侧以及在较大的玛丽亚外围的玛丽亚斑块中，较老的月海玄武岩年龄的优势，与西部近侧的较年轻的玄武岩年龄相反，即，在普罗卡勒鲁姆海洋来自最近国际月球探测器阿尔马达舰队的新数据将提供矿物学、地球化学、形态学、地形学和年龄数据，这些数据将进一步完善我们对月海玄武岩通量及其与成岩趋势和月球热演化的关系的理解。
The chronology of lunar volcanism is based on radiometric ages determined from Apollo and Luna landing site samples, regional stratigraphic relationships, and crater degradation and size-frequency distribution data for units largely defined prior to the end of the Apollo program. Accurate estimates of mare basalt ages are necessary to place constraints on the duration and the flux of lunar volcanism, as well as on the petrogenesis of lunar mare basalts and their relationship to the thermal evolution of the Moon. Here, we report on ages derived from crater size-frequency distribution measurements for exposed mare basalt units on the lunar nearside hemisphere. Crater size-frequency distribution measurements provide a statistically robust and accurate method to derive absolute model ages of unsampled regions on the Moon and other planetary surfaces. This paper summarizes and synthesizes results from our crater-counting efforts over more than 10 yr. We have dated basalts in Oceanus Procellarum, Imbrium, Serenitatis, Tranquillitatis, Humboldtianum, Australe, Humorum, Nubium, Cognitum, Nectaris, Frigoris, and numerous smaller occurrences like impact craters and sinus and lacus areas. Our investigations show that (1) in the investigated basins, lunar volcanism was active for almost 3 b.y., starting at similar to 3.9-4.0 b.y. ago and ceasing at similar to 1.2 b.y. ago, (2) most basalts erupted during the late Imbrian Period at similar to 3.6-3.8 b.y. ago, (3) significantly fewer basalts were emplaced during the Eratosthenian Period, and (4) basalts of possible Copernican age have been found only in limited areas in Oceanus Procellarum. Our results confirm and extend the general distribution of ages of mare basalt volcanism and further underscore the predominance of older mare basalt ages in the eastern and southern nearside and in patches of maria peripheral to the larger maria, in contrast to the younger basalt ages on the western nearside, i.e., in Oceanus Procellarum. New data from the recent international armada of lunar spacecraft will provide mineralogical, geochemical, morphological, topographic, and age data that will further refine our understanding of the flux of lunar mare basalts and their relation to petrogenetic trends and lunar thermal evolution.