TRIASSIC RADIOLARIA FROM USON ISLAND, PHILIPPINES

菲律賓北巴拉灣地塊烏松島三疊紀放射蟲之研究

葉貴玉(KUEI-YU YEH)

《Collection and Research》 3期 (1992/05) Pp. 51-91

https://doi.org/10.6693/CAR.1992.3.2

摘要

Triasic radiolarian faunas were discovered from the bedded cherts of Uson Island, North Palawan Block, Philippines. By correlating with the radiolarians from previous studies, the ages of Uson radiolarian faunas are dated as late Ladinian, late Carnian, late Norian, and early Rhaetian, respectively. This report illustrates the major radiolarian taxa from Uson Island discovered in this study. Only those forms with better preservation were described herein. The bedded cherts in Uson Island are litholog-ically similar to those in the Busuanga Island. It is believed that the Uson cherts are parts of the Limnangcong chert which is widely distributed in the North Palawan Block. Only Triassic radiolarians have been discovered from Uson Island. The results of this study indicate that the upper Upper Triassic (Rhaetian) section of the Liminangcong chert exists in Uson Island.

關鍵字

Radiolaria ； Triassic ； Philippines

並列摘要

經三次野外調査，總共採集並分析了七十幾個燧石岩層標本，結果在菲律賓北巴拉地塊的烏松島上僅發現三疊紀放射蟲的存在。與目前已知的放射蟲比對之結果，鳥松島之三疊紀放射蟲大致可區分成四個族群，即一個晚中三疊(late Ladinian)，及三個上三疊的族群，(late Carnian，late Norian，and early Rhaetian)。本文旨在描述烏松島三疊紀放射蟲族群中的重要種屬。由於再結晶作用使許多放射蟲保存不良而僅能將其鑑定至屬。但從本研究之結果仍可歸納出以下三點結論：1. 烏松島上之燧石岩層在外觀上與布希安哥島上的燧石岩極爲相似。作者相信其爲理明南康燧石岩(Liminangcong chert)的一部份。2. 在布希安哥島上出現的古生代、侏羅紀及大部分的三疊紀放射蟲族群都未曾在烏松島上被發現。同樣地，在烏松島出現的晚三疊(Rhaetian)族群也尙未在布希安哥島的岩層中觀察到。因此，兩島上所出露的燧石岩層很可能都只是理明南康燧石岩的片斷，但布希安哥島上的岩層跨越的年代較長，而烏松島上可能只保留從晚中三疊紀至晚上三疊紀的部分岩層。3. 烏松島放射蟲族群的發現，除可增進世人對晚三疊紀放射蟲的認識外，並對理明南康燧石岩上三疊岩層之下落提供了具體的證據。

並列關鍵字

放射蟲 ； 三疊紀 ； 菲律賓