Microscopy analysis of soils at the Phoenix landing site, Mars: Classification of soil particles and description of their optical and magnetic properties
Microscopy analysis of soils at the Phoenix landing site, Mars: Classification of soil particles and description of their optical and magnetic properties
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DOI：
10.1029/2009je003437
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发表时间：
2010-08-04
影响因子：
4.8
通讯作者：
Tanner, R.
中科院分区：
文献类型：
--
作者：
Goetz, W.;Pike, W. T.;Tanner, R.
凤凰号航天器上的光学显微镜已经返回了土壤的彩色图像（4 μ m像素（-1）），这些图像被传送到各种基质上并保持在各种基质上。根据颜色、大小和形状，对菲尼克斯土壤颗粒进行了初步分类，确定了以下颗粒类型[括号中的通用名称]：（1）红色细粉，大部分未溶解，光谱类似于（尽管颜色略深）全球气载尘埃[红色细粉]，（2）粉砂至砂大小的褐色颗粒[棕色砂]，（3）粉砂至砂大小的黑色颗粒[黑色砂]，和（4）少量白色细粉，可能是盐[白色细粉]。大多数粒子的饱和磁化强度在0.5-2 Am-2 kg（-1）范围内，这是从它们与磁性基质的相互作用推断出来的。颗粒大小分布有两个明显的峰值低于10 μ m（细粉）和范围20-100 μ m（颗粒），分别是不同的涟漪土壤在古谢夫陨石坑。特别是中等至大沙粒似乎是不存在的凤凰土壤。大多数沙粒都是近圆形的，具有不同的纹理。一个破碎的晶粒（观察溶胶112）揭示了微米级的晶体刻面的证据。棕砂类别显示出很大的颜色多样性，包括有光泽的，几乎无色的颗粒。这些颗粒的潜在来源区域可能是塔尔西斯火山或海姆达尔陨石坑（着陆点以东20公里）。黑色颗粒被认为是属于一个更广泛的人口与镁铁质矿物颗粒。黑色/棕色复合颗粒的缺乏是一致的不同的形成途径和源区的每种颗粒类型。
The optical microscope onboard the Phoenix spacecraft has returned color images (4 mu m pixel(-1)) of soils that were delivered to and held on various substrates. A preliminary taxonomy of Phoenix soil particles, based on color, size, and shape, identifies the following particle types [generic names in brackets]: (1) reddish fines, mostly unresolved, that are spectrally similar to (though slightly darker than) global airborne dust [red fines], (2) silt-to sand-sized brownish grains [brown sand], (3) silt-to sand-sized black grains [black sand], and (4) small amounts of whitish fines, possibly salts [white fines]. Most particles have a saturation magnetization in the range 0.5-2 Am-2 kg(-1) as inferred from their interaction with magnetic substrates. The particle size distribution has two distinct peaks below 10 mu m (fines) and in the range 20-100 mu m (grains), respectively, and is different from that of ripple soils in Gusev crater. In particular medium to large sand grains appear to be absent in Phoenix soils. Most sand grains have subrounded shape with variable texture. A fractured grain (observed on sol 112) reveals evidence of micrometer-sized crystal facets. The brown sand category displays a large diversity in color including shiny, almost colorless particles. Potential source regions for these grains may be the Tharsis volcanoes or Heimdal crater (20 km east of the landing site). The black grains are suggested to belong to a more widespread population of particles with mafic mineralogy. The absence of black/brown composite grains is consistent with different formation pathways and source regions for each grain type.