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有沙子在南极吗?

有一首歌“暴雪从未见过沙漠的沙子”。南极洲是一个沙漠,有人质疑标题的有效性。但有沙子在南极吗?

我想是的,因为它是一个非常基本的土壤和南极洲是一个大的地方,我知道有土地质量,不仅仅是冰,在南极洲。不过我不确定——任何更多信息或证据沙子的存在呢?

回答

简单的答案是:当然可以。沙子被定义为一个失去粒状材料颗粒之间的0.074和4.75毫米直径(我们定义)或0.0625到0.2毫米(温特沃斯,1922年)。还有一个对数刻度称为φ规模(Krumbein 1934)。约之间基本上颗粒大小。0.05到2毫米被定义为砂。哪里有地方暴露沉积物,沉积物的将会在沙滩上分数。获得“纯”砂是必要的,一些沉积物分类代理行为。这可以通过风、流水(河流)和波浪作用。这些过程会不同程度解决某些晶粒大小和提供有限的粒度分布的累积。所有的运输过程倾向于某种材料在某种程度上。 Wind is most limiting, whereas flowing water and wave action is less so but in all cases the sorting depends on the energy provided to move the sediment. Since Antarctica is largely covered by ice there are not large areas exposed to wave action, flowing river water or wind. But along the shore of the Antarctic peninsula there are many sediment beaches exposed to wind and wave action. In addition, the Dry Valleys area is a low precipitation area that has experienced dry desert conditions for maybe 2 Ma (Fountain et al 1999). In such areas there is ample opportunity for sorting processes to generate well sorted sediments and hence sands. Whether sands will accumulate in the form of dunes or be deposited in other landforms depend on the processes in the area and where sediments accumulate. Many beaches on the Antarctic peninsula are for example dominated by boulders because the smaller fractions are eroded away to more protected bays. This is common in all environments. So sands are present in Antarctica for the same reasons as sands appear elsewhere on the Earth. Limitations come from the area exposed to sorting processes in Antarctica since much sediment is covered by glacier ice. We also need to remember that glacier ice is to a large extent responsible for creating smaller fractions of sediment due to crushing processes (Hooke and Iverson, 1998) References: Fountain AG, Lyons WB, Burkins MB, Dana GL, Doran PT, Lewis KJ, McKnight DM, Moorhead DL, Parsons AN, Priscu JC, Wall DH, Wharton RA, Virginia RA, 1999. Physical Controls on the Taylor Valley Ecosystem, Antarctica. BioScience. 49 (12), 961–971. doi:[10.2307/1313730][1]. Hooke, RLeB, Iverson, NR, 1995. Grain-size distribution in deforming subglacial tills: Role of grain fracture. Geology 23 (1), 57–60. doi:[10.1130/0091-7613(1995)023<0057:GSDIDS>2.3.CO;2][2] Krumbein WC, 1934. Size frequency distributions of sediments. Journal of Sedimentary Petrology. 2 (4), doi:[10.1306/D4268EB9-2B26-11D7-8648000102C1865D][3]. Wentworth CK, 1922 A Scale of Grade and Class Terms for Clastic Sediments. The Journal of Geology, 30 (5), 377-392. doi:[10.1086/622910][4] [1]: https://doi.org/10.1525/bisi.1999.49.12.961 [2]: https://doi.org/10.1130/0091-7613(1995)023%3C0057:GSDIDS%3E2.3.CO;2 [3]: https://doi.org/10.1306/D4268EB9-2B26-11D7-8648000102C1865D [4]: https://doi.org/10.1086/622910

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