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Clay fractions in the non-calcareous surface sediments from the eastern Pacific were ana- lyzed for clay minerals, REE and 143Nd/144Nd. Montmorillonite/illite ratio (M/I ratio), total REE contents (ΣREE), LREE/HREE ratio and cerium anomaly (δ Ce) may effectively indicate the genesis of clay min- erals. Clay fractions with M/I ratio >1, δ Ce <0.85, ΣREE >400 μg/g, LREE/HREE ratio ≈4, and REE patterns similar to those of pelagic sediments are terrigenous and autogenetic mixed clay fractions and contain more autogenetic montmorillonite. Clay fractions with M/I ratio <1, δ Ce=0.86 to 1.5, ΣREE=200 to 350 μg/g, LREE/HREE ratio ≈6 and REE distribution patterns similar to that of China loess are identi- fied as terrigenous clay fraction. The 143Nd/144Nd ratios or εNd values of clay fractions inherit the features of terrigenous sources of clay minerals. Clay fractions are divided into 4 types according to εNd values. Terrigenous clay minerals of type I with the εNd values of ?8 to ?6 originate mainly from North American fluvial deposits. Those of type II with the εNd values of ?9 to ?7 are mainly from the East Asia and North American fluvial deposits. Those of type III with εNd values of ?6 to ?3 could come from the central and eastern Pacific volcanic islands. Those of type IV with εNd values of ?13 to ?12 may be from East Asia eolian. The terrigenous and autogenetic mixed clay fractions show patchy distributions, indicating that there are volcanic or hot-spot activities in the eastern Pacific plate, while the terrigenous clay fractions cover a large part of the study area, proving that the terrigenous clay minerals are dominant in the eastern Pacific.
Clay fractions in the non-calcareous surface sediments from the eastern Pacific were ana lyzed for clay minerals, REE and 143 Nd / 144 Nd. Montmorillonite / illite ratio (M / I ratio), total REE contents (ΣREE), LREE / HREE ratio and Clay fractions with M / I ratio> 1, δ Ce <0.85, ΣREE> 400 μg / g, LREE / HREE ratio ≈4, and REE similar Clay fractions with M / I ratio <1, δ Ce = 0.86 to 1.5, ΣREE = 200 to 350 μg / g, LREE / HREE ratio ≈6 and REE distribution patterns similar to that of China loess are identi- fied as terrigenous clay fraction. The 143Nd / 144Nd ratios or εNd values of clay fractions inherit the features of terrigenous sources of clay minerals. Clay fractions are divided into 4 types according to εNd values. Terrigenous clay minerals of type I with the εNd values of? 8 Those of type II with the εNd values of? 9 to? 7 are mainly from the East Asia and North American fluvial deposits. Those of type III with εNd values of? 6 to? 3 could have from the central and eastern Pacific volcanic islands. Those of type IV with εNd values of? 13 to? 12 may be from East Asia eolian. The terrigenous and autogenetic mixed clay fractions show patchy distributions, indicating that there are volcanic or hot- spot activities in the eastern Pacific plate, while the terrigenous clay fractions cover a large part of the study area, proving that the terrigenous clay minerals are dominant in the eastern Pacific.