亚马逊纪

亚马逊纪（Amazonian）是火星上一个地质系统和地质年代，其特征是陨石和小行星撞击率非常低，极度干燥、寒冷的环境与今天火星上的情况大致相似Tanaka, K.L. (1986). The Stratigraphy of Mars. J. Geophys. Res., Seventeenth Lunar and Planetary Science Conference Part 1, 91(B13), E139–E158.Carr, M.H. (2006), The Surface of Mars. Cambridge Planetary Science Series, Cambridge University Press.。它与前一期的赫斯珀里亚纪过渡有些模糊，被认为约开始于30亿年前，尽管这一日期的误差非常大（约5亿年）Werner, S. C., and K. L. Tanaka (2011), Redefinition of the crater-density and absolute-age boundaries for the chronostratigraphic system of Mars, Icarus, 215(2), 603–607, .。有时，亚马逊纪又被细分为早、中和晚亚马逊世，亚马逊纪一直延续到今天。

亚马逊纪时期主要是撞击坑的形成和风成作用，在塔尔西斯和科柏洛斯槽沟持续发生孤立的火山活动，包括后者在数万年前和奥林帕斯山过去几百万年内的活动迹象，这意味着它们仍然可能活跃，只是目前处于休眠状态。

名称来源及描述

“亚马逊”系和“亚马逊”纪是以陨坑分布稀疏的亚马逊平原所命名，这种稀疏的陨坑密度代表了许多亚马逊纪时期的地表。亚马逊系的典型地貌区约位于亚马逊区（MC-8）北纬15度、西经158度附近。 

火星地质年代期 (百万年前)

亚马逊年代和地层

由于它是火星地质时期中最年轻的一段，亚马逊纪的年表通过传统地质叠覆律结合撞击坑计数的相对测年技术得到了比较好的理解。亚马逊纪陨石坑稀疏的特点也意味着，与古老年代不同，它的表面精细特征（尺寸<100米）都得以保留Irwin, R.P., Tanaka, K.L., and Robbins, S.J., 2013, Distribution of Early, Middle, and Late Noachian cratered surfaces in the Martian highlands: Implications for resurfacing events and processes: Journal of Geophysical Research, v. 118, p. 278–291, .。由于火星表面必要的形态细节仍然清晰可见，这将可能对许多亚马逊纪时代火星表面的特征进行详细的、面向过程的研究。

此外，这一相对年轻的时期意味着仍有可能重建太阳、火星和木星在过去1亿年中的轨道力学统计数据，而不会被混沌效应所混淆，并由此再现太阳辐射量的变化-随时间推移抵达火星的太阳热量 Laskar, J., Correia, A.C.M., Gastineau, M., Joutel, F., Levrard, B., and Robutel, P., 2004, Long term evolution and chaotic diffusion of the insolation quantities of Mars: Icarus, v. 170, no. 2, p. 343–364, .。火星上周期性发生的气候变化已证明在规模量级和持续时间上与地球米兰科维奇循环基本没有差异。

总之，这些保存良好的特征以及对所接收到的太阳光通量的理解—意味着对火星亚马逊纪的许多研究都集中在了解其气候和地表运动过程对气候的响应，这包括：

冰川动态和地貌Dickson, J.L., Head, J.W., III, and Marchant, D.R., 2010, Kilometer-thick ice accumulation and glaciation in the northern mid-latitudes of Mars: Evidence for crater-filling events in the Late Amazonian at the Phlegra Montes: Earth and Planetary Science Letters, v. 294, no. 3-4, p. 332–342, .；
火星上冰的消涨Head, J.W., III, Mustard, J.F., Kreslavsky, M.A., Milliken, R.E., and Marchant, D.R., 2003, Recent ice ages on Mars: Nature, v. 426, p. 797–802.；
地面冰的性状及其产生的冰缘形式Levy, J.S., Head, J.W., III, and Marchant, D.R., 2009, Concentric crater fill in Utopia Planitia: History and interaction between glacial “brain terrain” and periglacial mantle processes: Icarus, v. 202, p. 462–476, .；
融化过程和小型河流地貌Fassett, C.I., Dickson, J.L., Head, J.W., III, Levy, J.S., and Marchant, D.R., 2010, Supraglacial and proglacial valleys on Amazonian Mars: Icarus, v. 208, no. 1, p. 86–100, .Salese, F., G. Di Achille, A. Neesemann, G. G. Ori, and E. Hauber (2016), Hydrological and sedimentary analyses of well-preserved paleofluvial-paleolacustrine systems at Moa Valles, Mars, J. Geophys. Res. Planets, 121, 194–232, .；
大气层特性的变化Leblanc, F., and R. E. Johnson. "Role of molecular species in pickup ion sputtering of the Martian atmosphere." Journal of Geophysical Research: Planets (1991–2012) 107.E2 (2002): 5-1.；
地下水动态Burr, D.M., Grier, J.A., McEwen, A.S., and Keszthelyi, L.P., 2002, Repeated Aqueous Flooding from the Cerberus Fossae: Evidence for Very Recently Extant, Deep Groundwater on Mars: Icarus, v. 159, no. 1, p. 53–73, .；
冰盖动态Kolb, Eric J., and Kenneth L. Tanaka. "Geologic history of the polar regions of Mars based on Mars Global Surveyor data: II. Amazonian Period." Icarus 154.1 (2001): 22-39.；
二氧化碳霜冻动态以及与之相关的奇异表面特征，如“蜘蛛”Kieffer, Hugh H., Philip R. Christensen, and Timothy N. Titus. "CO2 jets formed by sublimation beneath translucent slab ice in Mars' seasonal south polar ice cap." Nature 442.7104 (2006): 793-796.；
风对沙和尘沉积物的作用以及常规风成沉积Balme, Matt, et al. "Transverse aeolian ridges (TARs) on Mars." Geomorphology 101.4 (2008): 703-720.Basu, Shabari, Mark I. Richardson, and R. John Wilson. "Simulation of the Martian dust cycle with the GFDL Mars GCM." Journal of Geophysical Research: Planets (1991–2012) 109.E11 (2004).；
过去气候环境（风场、温度、云层特性、大气化学）本身的建模Read, Peter L., and Stephen R. Lewis. The Martian climate revisited: Atmosphere and environment of a desert planet. Springer Verlag, 2004.Jakosky, Bruce M., and Roger J. Phillips. "Mars' volatile and climate history." nature 412.6843 (2001): 237-244.。

良好的保存状况，也使人们能够对亚马逊纪火星上的其他地质过程进行详细研究，特别是火山活动Mangold, N., et al. "A Late Amazonian alteration layer related to local volcanism on Mars." Icarus 207.1 (2010): 265-276.Hartmann, William K., and Daniel C. Berman. "Elysium Planitia lava flows: Crater count chronology and geological implications." Journal of Geophysical Research: Planets (1991–2012) 105.E6 (2000): 15011-15025.Neukum, Gerhard, et al. "Recent and episodic volcanic and glacial activity on Mars revealed by the High Resolution Stereo Camera." Nature 432.7020 (2004): 971-979.、脆性构造Márquez, Álvaro, et al. "New evidence for a volcanically, tectonically, and climatically active Mars." Icarus 172.2 (2004): 573-581.Mueller, Karl, and Matthew Golombek. "Compressional structures on Mars." Annu. Rev. Earth Planet. Sci. 32 (2004): 435-464.和陨坑的形成等Robbins, Stuart J., and Brian M. Hynek. "Distant secondary craters from Lyot crater, Mars, and implications for surface ages of planetary bodies." Geophysical Research Letters 38.5 (2011).Malin, Michael C., et al. "Present-day impact cratering rate and contemporary gully activity on Mars." science 314.5805 (2006): 1573-1577.Popova, Olga, Ivan Nemtchinov, and William K. Hartmann. "Bolides in the present and past Martian atmosphere and effects on cratering processes." Meteoritics & Planetary Science 38.6 (2003): 905-925.。

系统与年代

“系”和“纪”在正式地层命名法中是不可互换的，尽管它们在流行读物中经常被混淆。系是一种理想化的地层柱，它基于某一典型区域（典型剖面）的物理岩石记录，这一记录与全球许多不同位置的岩石剖面相关联Eicher, D.L.; McAlester, A.L. (1980).History of the Earth; Prentice-Hall: Englewood Cliffs, NJ, pp 143-146, .。一种系与上下相邻的边界地层有明显不同的特征（在地球上，通常是标准化石），表明主要动物群或环境条件发生了显著（通常为突发性的）改变（参见白垩纪-古近纪边界示例）。

在任何地方，给定地层系中的岩石剖面都容易包含空隙（不一致），就像书中的缺页。在某些地方，由于未产生沉积或后来的侵蚀，该系中的岩石完全缺失。例如，美国中东部内陆大部分地区都不存在白垩纪系的岩石，但是，那里肯定仍经历过白垩纪时期。因此，地质时期代表形成该地层系的沉积时段，且包含所有空隙中存在的未知时长。时期以年为单位，由放射性定年确定。在火星上，除了来源于地层背景未知的火星陨石外，无法获得放射性年龄。相反，火星上的绝对年龄是由撞击坑密度决定的，这在很大程度上取决于随时间变化的陨石坑形成模型Masson, P.; Carr, M.H.; Costard, F.; Greeley, R.; Hauber, E.; Jaumann, R. (2001). Geomorphologic Evidence for Liquid Water. Space Science Reviews, 96, p. 352.。因此，火星各时期准确的开始和结束时间都无法确定，尤其是赫斯珀里亚/亚马逊边界，其误差可能达到2或3倍Nimmo, F.; Tanaka, K. (2005). Early Crustal Evolution of Mars. Annu. Rev. Earth Planet. Sci., 33, 133–161.Hartmann, W.K.; Neukum, G. (2001). Cratering Chronology and Evolution of Mars. In Chronology and Evolution of Mars, Kallenbach, R. et al. Eds., Space Science Reviews, 96: 105–164.。

图集

另请查看
火星地质史 
火星地質

备注和参引

参考书目和推荐阅读
Boyce, Joseph, M. (2008). The Smithsonian Book of Mars; Konecky & Konecky: Old Saybrook, CT, 
Carr, Michael, H. (2006). The Surface of Mars; Cambridge University Press: Cambridge, UK, .
Hartmann, William, K. (2003). A Traveler’s Guide to Mars: The Mysterious Landscapes of the Red Planet; Workman: New York, .
Morton, Oliver (2003). Mapping Mars: Science, Imagination, and the Birth of a World; Picador: New York, .

Category:火星地质年代
Category:挪亚区
Category:地层单位