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位于黄土高原东南缘的三门峡红粘土地层 ,以陕县指望剖面为其典型代表。厚度为 74 .3m的指望剖面由上部厚 34m的黄土地层和下伏厚 4 0 .3m的红粘土沉积组成 ,黄土为 L2 4 — L33的连续风尘沉积 ,下部红粘土为RS1 — RS5的沉积。磁性地层研究显示 :M/Ga界线位于 33.8m处 ,黄土与红粘土界线之上 2 0 cm ,Ga/Gi界线位于5 6 .2 5 m处的 RS3中下部。该区红粘土为近 5 Ma至 2 .6 Ma的风尘沉积夹河湖相沉积。指望剖面的红粘土地层磁化率较黄土高原内部偏高 ,总体特征一致 ,说明近 5 Ma来东亚季风在区域演化上的一致性。
Located in the southeastern margin of the Loess Plateau of the Sanmenxia red clay strata, Shaanxi Province, as the typical representative of the profile. The predicted section with a thickness of 74.3m consists of a loess layer with a thickness of 34m at the top and a red clay deposit with a thickness of 403m under the ground. Loess is a continuous dust deposition of L2 4 - L33 and RS1 - RS5 is deposited in the lower red clay. Magnetic stratum studies show that the M / Ga boundary is located at 33.8m, the loess and red clay boundary is above 20 cm, and the Ga / Gi boundary is located at the middle and bottom of RS3 at 56.55 m. The red clay in this area is the sedimentary Jiahe lacustrine facies deposited in the dustfall of nearly 5 Ma to 2.6 Ma. The magnetic susceptibility of the red clay strata in the expectation profile is higher than that in the Loess Plateau, and the general characteristics are consistent, which shows the consistency of the East Asian monsoon in the regional evolution in the recent 5 Ma.