- 作者: 陳汝勤
- 作者服務機構: 台大海洋研究所
- 中文摘要: 筆者研究了由九連號在台灣海峽北部所採集所三十二個標本的礦物及化學成份,由X光鑑定之礦物成份為石英、長石、綠泥石、伊利石、高嶺石、方解石、霰石,角閃石及赤鐵礦,在此等沉積物中以光學鑑定之重礦物有磁鐵礦,鉉鐵礦、獨居石,金紅石,鋯石,石榴子石及輝石類,一般言之沉積物中石英/方解石比率隨岸距之增大而減少顯示生物沉積在遠離海岸處影響甚大,石英/長石之比率常隨岸距之增加大增大此可能由於長石經長期搬運後產生變化或分解之故,Fe ,Mn, Cu, Cr, Co及Ni等之化學分析係以原子吸光儀行之三十二個標本之成份如下ΣFe2O3 3.44-7.22%平均4.44%. Mn 0 0.033-0.445彫平均0.168%,Cu 4.3-21.6 ppm平均9.lppm, Cr 24-80 ppm平均55ppm, Co 8.8-38.6 ppm平均21.3 ppm, Ni 7.7-65.7ppm平均24.6 ppm.在沉積物中Cr, Co, Ni與Fe之間有正比關係,筆者發現沉積物之重金屬含量與鐵鎂礦物及黏土礦物之問有密切關係,筆者認為源區與沉積環境是控制沉積物礦物及化學成份之主要因素。
- 英文摘要: Thirty two samples of shelf sediments collected by R/V Chiu Lien in thenorthern part of the Taiwan Strait have been studied mineralogically and che-mically. Quartz, feldspar, chlorite, illite, kaolin, calcite, aragonite, amphibo-le and hematite have been found in the X-ray analyzed smaples. Heavyminerals in the sediments identified optically include magnetite, ilemenite,monazite, rutile, zircon, garnet and pyroxenes. In general the quartz/calciteratios in the sediments decrease when the offshore distances increase sugge-sting that biogenic contributions become increasingly more important awayfrom the shoreline. The quartz/feldrpar ratios tend to increase slightly withthe offshore distances. This might be due to increasing alteration and/ordecompsition of feldspars in relation to distance of transportation. Thechemical analyses for Fe, Mn, Cu, Cr, Co and Ni were carried out with aPerkin-Elmer Model 303 atomic absorption spectrophotometer. The range andaverage of the thirty two samples are Fe2O3 3.44-7.22% average 4.44%; MnO 0.033-0.445% average 0.168%; Cu 4.3-21.6 ppm average 9.1 ppm; Cr 24-80ppm average 55 ppm; Co 8.8-38.6 ppm average 21.3 ppm and Ni 7.7-65.7ppm average 24.6 ppm. The three samples with relatively high iron contentgenerally are located in the near-shore area. Positive correlation betweenCr, Co, Ni and Fe has been found in the sediments. The havy metal dist-ribution in the shelf sediments are closely related to the occurrence of land-derived ferromagnesian and clay minerals. It is suggegted that the proven-ance and environment effects are the most important factors contorllingthe mineralogical and chemical variation in the sediments.
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