DISTRIBUTION OF FORAMINIFERA AND SEDIMENTS, PERU-CHILE TRENCH AREA
DISTRIBUTION OF FORAMINIFERA AND SEDIMENTS, PERU-CHILE TRENCH AREA
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DOI：
10.1016/0011-7471(64)90951-9
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发表时间：
1964-01-01
期刊：
影响因子：
--
通讯作者：
RODOLFO, KS
中科院分区：
文献类型：
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作者：
BANDY, OL;RODOLFO, KS
18拖网样品，彼得森抓斗，和13个Phleger核心之间的深度179和6250米，在秘鲁-智利海沟地区关闭南美洲西海岸。沉积物主要是橄榄绿色的粉砂、粘土和胶体物质;然而，四个岩心含有大量的砂大小的有孔虫或页岩碎片，其中一个岩心主要是白色火山灰。半深海区的有机碳和氮值比深海区高得多。沉积物颗粒大小并不随水深或距海岸的距离而呈现明确的趋势。碳酸钙含量在3500米以下急剧下降，反映了海沟中钙质有孔虫数量的减少。在1500米以上的深度，放射虫的数量通常是有孔虫的两倍多。拖网样品中直径大于0.5mm的有孔虫较为集中，1000 m以下主要为砂质有孔虫。在较小的有孔虫中，钙质形式在2000米以下占主导地位;在更深处，钙质-砂质比例波动极大。半深海带的浮游有孔虫化石最多。深海有孔虫分带的依据是拖网中较大活有孔虫和岩芯中较小有孔虫出现的上限。估计每一拖网捕获的物质总量为2至约43公斤（干重）。仅限于深水的物种似乎是从耐深的祖先进化而来的。
Eighteen trawl samples, one Petersen grab, and thirteen Phleger cores were collected between depths of 179 and 6250 m in the Peru-Chile Trench area off the west coast of South America. Sediments are mainly olive-green silt, clay and colloidal material; however, four cores contain significant amounts of either sand-sized foraminifera or shale fragments, and one of these cores is mainly white volcanic ash. Values for organic carbon and nitrogen are much higher in the bathyal than in the abyssal zone. Sediment grain sizes do not exhibit definitive trends with either water depth or distance from shore. Calcium carbonate contents decrease sharply below 3500 m, reflecting reduced quantities of calcareous foraminifera in the Trench. Radiolarians are usually more than twice as abundant as foraminifera deeper than 1500 m. Foraminifera larger than 0.5 mm were concentrated in the trawl samples and are mainly arenaceous types below 1000 m. Among the smaller foraminifera, calcareous forms predominate down to 2000 m; at greater depths calcareous-arenaceous ratios fluctuate extremely. Tests of planktonic foraminifera are most abundant in the bathyal zone. Bathymetric foraminiferal zonation is based upon upper limits of occurrence for both the larger live foraminifera from the trawls and the smaller foraminifera from the cores. Maximum size of the larger foraminifera is usually between 1 and 10 mm. Estimates of the total volumes of material caught by each trawl range from 2 to about 43 kg, dry wt. Species restricted to deep water appear to have evolved from depth-tolerant ancestors.