Stratigraphy and Isotope Ages of Lunar Geologic Units: Chronological Standard for the Inner Solar System
Stratigraphy and Isotope Ages of Lunar Geologic Units: Chronological Standard for the Inner Solar System
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DOI：
10.1023/a:1011937020193
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发表时间：
2001-04
影响因子：
10.3
通讯作者：
D. Stöffler;G. Ryder
中科院分区：
文献类型：
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作者：
D. Stöffler;G. Ryder
包括火星在内的内太阳系陨石坑表面的绝对年龄是由月球的撞击通量曲线外推得到的，该曲线是根据月球样品的绝对年龄校准的。我们利用月球样品的同位素年龄和月球地层学的最新观点，以及月球地质表面单元的相对和绝对年龄测定原理，重新评估了月球通量曲线。描述了阿波罗和露娜着陆区的地质背景，只要它们与这次重新评估有关。我们给出了多环盆地及其相关喷出盖层的最佳年龄估计，并给出了盆地事件的替代年龄(括号内)：Nectaris为3.92±0.03Gyr(或3.85±0.05Gyr)，Cs为3.89±0.02Gyr(或3.84±0.04Gyr)，Serenatis为3.89±0.01Gyr(或3.87±0.03Gyr)，以及Imbrium为3.85±0.02Gyr(或3.77±0.02Gyr)。阿波罗11号(老表面)、阿波罗17号(3.75±0.01Gyr)、阿波罗11号(年轻表面)、露娜16号(3.41±0.04 Gyr)、阿波罗15号(3.30±0.02 Gyr)、露娜24号(3.22±0.02 Gyr)、阿波罗12号(3.15±0.04 Gyr)。Gyr(Autolycus)，800±15 Myr(哥白尼)，109±4 Myr(第谷)，50.3±0.8(北射线陨石坑，阿波罗16)，25.1±1.2(圆锥形陨石坑，阿波罗14)。当将这些数据与相关月球表面单位的陨石坑密度作图时，这些数据产生了修订的月球撞击通量曲线，该曲线在以下方面与以前使用的流量曲线不同：(1)地层学上最关键的撞击盆地的年龄明显年轻，(2)校准曲线的不确定性降低，特别是在约4.0至3.0 Gyr的年龄范围内，(3)超过3.95 Gyr(Nectaris喷出岩层的上限年龄)的任何曲线都被放弃，因为在这种表面地层上测量的陨石坑频率无法与从月球样品获得的绝对年龄相关联。因此，这一死亡前时间的冲击通量曲线仍然未知。新的月球陨石坑保留年龄小于3.9Gyr的校准曲线为包括火星在内的内太阳系天体提供了一个最新的标准参考。
The absolute ages of cratered surfaces in the inner solar system, including Mars, are derived by extrapolation from the impact flux curve for the Moon which has been calibrated on the basis of absolute ages of lunar samples. We reevaluate the lunar flux curve using isotope ages of lunar samples and the latest views on the lunar stratigraphy and the principles of relative and absolute age dating of geologic surface units of the Moon. The geological setting of the Apollo and Luna landing areas are described as far as they are relevant for this reevaluation. We derive the following best estimates for the ages of the multi-ring basins and their related ejecta blankets and present alternative ages for the basin events (in parentheses): 3.92 ± 0.03 Gyr (or 3.85 ± 0.05 Gyr) for Nectaris, 3.89 ± 0.02 Gyr (or 3.84 ± 0.04 Gyr) for Crisium, 3.89 ± 0.01 Gyr (or 3.87 ± 0.03 Gyr) for Serenitatis, and 3.85 ± 0.02 Gyr (or 3.77 ± 0.02 Gyr) for Imbrium. Our best estimates for the ages of the mare landing areas are: 3.80 ± 0.02 Gyr for Apollo 11 (old surface), 3.75 ± 0.01 Gyr for Apollo 17, 3.58 ± 0.01 Gyr for Apollo 11 (young surface), 3.41 ± 0.04 Gyr for Luna 16, 3.30 ± 0.02 Gyr for Apollo 15, 3.22 ± 0.02 Gyr for Luna 24, and 3.15 ± 0.04 Gyr for Apollo 12. The ages of Eratosthenian and Copernican craters remain: ~ 2.1 (?) Gyr (Autolycus), 800 ± 15 Myr (Copernicus), 109 ± 4 Myr (Tycho), 50.3 ± 0.8 (North Ray crater, Apollo 16), and 25.1 ± 1.2 (Cone crater, Apollo 14). When plotted against the crater densities of the relevant lunar surface units, these data result in a revised lunar impact flux curve which differs from the previously used flux curve in the following respects: (1) The ages of the stratigraphically most critical impact basins are notably younger, (2) the uncertainty of the calibration curve is decreased, especially in the age range from about 4.0 to 3.0 Gyr, (3) any curve for ages older than 3.95 Gyr (upper age limit of the Nectaris ejecta blanket) is abandoned because crater frequencies measured on such surface formations cannot be correlated with absolute ages obtained on lunar samples. Therefore, the impact flux curve for this pre-Nectarian time remains unknown. The new calibration curve for lunar crater retention ages less than about 3.9 Gyr provides an updated standard reference for the inner solar system bodies including Mars.