SIGNIFICANCE OF THICK DEPOSITS OF COLLUVIUM ON HILLSLOPES - A CASE-STUDY INVOLVING THE USE OF POLLEN ANALYSIS IN THE COASTAL MOUNTAINS OF NORTHERN CALIFORNIA
SIGNIFICANCE OF THICK DEPOSITS OF COLLUVIUM ON HILLSLOPES - A CASE-STUDY INVOLVING THE USE OF POLLEN ANALYSIS IN THE COASTAL MOUNTAINS OF NORTHERN CALIFORNIA
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DOI：
10.1086/628845
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发表时间：
1984-01-01
影响因子：
1.8
通讯作者：
DORN, R
中科院分区：
文献类型：
--
作者：
DIETRICH, WE;DORN, R
在覆土的山坡上，常见的是带有崩积物的明显基岩空洞。有人提出，这些空洞是经常性的地方清空滑坡和随后缓慢回填崩积物。在北方加州的一个山坡上，我们已经量化了自排空以来的时间和下伏基岩表面的三维结构。崩积物中的花粉记录与附近一个具有精确年龄控制的湖泊的花粉芯的相关性表明，最古老的崩积物沉积在基岩凹陷中11，000至13，500年。从那时起，崩积物在空洞中的沉积相当于周围源区景观降低1.5米，局部降低率约为0.1毫米/年。凹陷的纵向剖面是向上凹的，这种形式导致地下水流向斜坡下的表面上升，导致饱和并可能导致滑坡。
Distinct bedrock hollows with a colluvial fill are common in soil-mantled hillslopes. It has been proposed that these hollows are sites of recurrent emptying by landsliding and subsequent slower refilling with colluvium. On a hillslope in Northern California we have quantified the time since emptying and the three-dimensional configurations of the underlying bedrock surface. Correlation of the pollen record in the colluvium with a nearby pollen core from a lake with an accurate age control indicates that the oldest colluvium was deposited 11,000 to 13,500 years in the bedrock hollow. Since then deposition of colluvium in the hollow has been equivalent to 1.5 m of landscape lowering in the surrounding source area and to a local lowering rate of about 0.1 mm/yr. The longitudinal profile of the hollow is concave upward, a form that causes the groundwater flow to rise toward the surface downslope, leading to saturation and possibly to landsliding.