Clast size controls and longevity of Pleistocene desert pavements at Lathrop Wells and Red Cone volcanoes, southern Nevada
Clast size controls and longevity of Pleistocene desert pavements at Lathrop Wells and Red Cone volcanoes, southern Nevada
复制标题
内华达州南部拉斯罗普韦尔斯和红锥火山更新世沙漠路面的碎屑尺寸控制和寿命
DOI：
--
复制
发表时间：
2006
期刊：
影响因子：
--
通讯作者：
C. Harrington
中科院分区：
文献类型：
--
作者：
G. Valentine;C. Harrington
在干旱环境中，沙漠路面的形成与堆积土壤密切相关。在Lathrop威尔斯（75 - 80 ka）和红锥（约100万年），1 Ma）的火山（内华达州南部）形成了一种极好的路面母质，允许风成粉砂和细砂的渗透，首先堵塞了下面火山灰的孔隙空间，然后加积并形成了泡状A（Av）层。原始火山碎屑大小的变化提供了对促进路面和土壤形成的最小和最大碎屑大小的深入了解：当碎屑在最强的风下跳跃时，路面变得无效，而大于粗火山砾的碎屑无法形成联锁路面，从而促进淤泥堆积（Av发展所必需的）。与预测相反，所有路面海拔以上！400米将被重置后，晚更新世植被的进步，土壤和路面显示出两个火山之间的成熟度有明显的差异。这表明，路面和/或土壤经过数万年的缓慢发展，然后非常稳定，或者，如果它们被植被的发展破坏，随后的路面重新建立，具有更成熟的特征。
Formation of desert pavement and accretionary soils are intimately linked in arid environments. Well-sorted fallout scoria lapilli at Lathrop Wells (75‐80 ka) and Red Cone (ca. 1 Ma) volcanoes (southern Nevada) formed an excellent parent material for pavement, allowing infiltration of eolian silt and fine sand that first clogged the pore space of underlying tephra and then aggraded and developed vesicular A (Av) horizons. Variations in original pyroclast sizes provide insight into minimum and maximum clast sizes that promote pavement and soil formation: pavement becomes ineffective when clasts can saltate under the strongest winds, while clasts larger than coarse lapilli are unable to form an interlocking pavement that promotes silt accumulation (necessary for Av development). Contrary to predictions that all pavements above altitudes of !400 m would have been reset in their development after late Pleistocene vegetation advances, the soils and pavements show clear differences in maturity between the two volcanoes. This indicates that either the pavements and/or soils develop slowly over many tens of thousands of years and then are very stable, or, if they are disrupted by vegetation advances, subsequent pavements are re-established with successively more mature characteristics.