摘要
利用XRD和SEM觀察臺灣西南部新第三紀泥岩中之硫化鐵礦物，結果顯示其中含有黃鐵礦、少量硫複鐵礦和一難以定量之硫化鐵礦物。硫複鐵礦之產狀是由0.2-2 µm晶粒所組成一不規則狀集合體。黃鐵礦產狀則可分為以下四種：(1)莓狀體；(2)不規則狀集合體；(3)結核粒；(4)他形至半自形之個別晶粒。而其中黃鐵礦莓狀體中較粗粒之晶粒以及碎屑來源、產狀為他形至半自形之個別晶粒內皆可觀察到溶解的邊界和坑洞，暗示著黃鐵礦在沉積或成岩環境下並不穩定。另一未知之硫化鐵礦物主要產狀為沿粗粒片狀矽酸鹽，包括綠泥石、伊利石、白雲母和黑雲母之解理間形成長短不一的條狀集合體，晶粒粒徑極細小(<0.5 µm)，少數可能是屬極細粒晶粒所構成之莓狀體，部分片狀矽酸鹽則具有蝕變現象，硫化鐵礦物之晶粒細小與片狀矽酸鹽的成分不單純造成定性定量的困難。
大部分標本僅有黃鐵礦存在，岩象結果中可看到溶蝕十分嚴重，組成晶粒晶界已十分模糊之黃鐵礦不規則狀集合體和晶形較佳，具輕微溶蝕現象，晶粒大小約為1.0-1.5 µm之黃鐵礦莓狀體共存，此二種型態之黃鐵礦為不同期形成，幾乎已成平坦塊狀之集合體乃是第一期自生黃鐵礦經過長時間溶蝕所造成。推斷早期生成之黃鐵礦經溶蝕作用後，提供材料予第二期較小規模之黃鐵礦莓狀體形成。自生黃鐵礦至少有兩期的生長。
僅有一標本中觀察到唯一一個硫複鐵礦，且該標本中亦含有邊界具溶解特徵之黃鐵礦，加上大部分標本中僅有黃鐵礦的出現，這樣的結果顯示硫複鐵礦應為黃鐵礦之後的產物，這樣的推論較能合理解釋新第三紀泥岩之磁極紀錄為何相反於沉積年代之現象，也暗示後沉積作用形成之硫複鐵礦可能在泥岩中是一相當普遍的現象。

目錄

第一章 緒論 --------------------------------------------------------- 1
1.1 前言 --------------------------------------------------------------- 1
1.2 前人研究 -------------------------------------------------------- 2
1.3 研究目的 --------------------------------------------- 4
第二章 地質背景 --------------------------------------------------- 5
第三章 研究方法 --------------------------------------------------- 7
第四章 結果 ------------------------------------------------------- 17
4.1 晚中新世岩樣之礦物學與岩象組織 ------------------- 17
4.1.1 硫化鐵礦物 ------------------------------------------------ 17
4.1.2 氧化鐵礦物 ------------------------------------------------ 19
4.1.3 粗粒片狀矽酸鹽礦物 ----------------------------------- 19
4.1.4 其他礦物 --------------------------------------------------- 20
4.2 早上新世岩樣之礦物學與岩象組織 ------------------- 22
4.2.1 硫化鐵礦物 ------------------------------------------------ 22
4.2.2 氧化鐵礦物 ------------------------------------------------- 26
4.2.3 粗粒片狀矽酸鹽礦物 ------------------------------------ 26
4.2.4 其他礦物 ---------------------------------------------------- 27
4.3 晚上新世岩樣之礦物學與岩象組織 ------------------ 27
4.3.1 硫化鐵礦物 ------------------------------------------------ 27
4.3.2 氧化鐵礦物 ------------------------------------------------- 32
4.3.3 粗粒片狀矽酸鹽礦物 ----------------------------------- 32
4.3.4 其他礦物 ---------------------------------------------------- 32
4.4 硫化鐵礦物之產狀 ----------------------------------------- 33
第五章 討論 ------------------------------------------------------- 35
5.1各硫化鐵礦物之生長時序 ---------------------------- 35
5.2探討各硫化鐵礦物與成岩作用之關聯 --------------- 37
5.3 硫化鐵礦物形成機制與地質環境之關係 ------------- 37
第六章 結論 ------------------------------------------------ 39
參考文獻 ------------------------------------------------------- 40
照片 ------------------------------------------------------------ 45

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