著者
江藤 哲人
出版者
横浜国立大学教育学部
雑誌
横浜国立大学理科紀要 第ニ類 生物学・地学 (ISSN:05135613)
巻号頁・発行日
no.33, pp.p67-105,図4枚,表1枚, 1986-12
被引用文献数
2

The late Cenozoic strata occupy the Miura Peninsula situated in the southern Kanto region. The author has been studying the geology of the Cenozoic sequence of the Miura Peninsula and the neighboring areas. The purpose of the study is to clarify the characteristics of the Cenozoic tectonics and the geologic history of the areas. The Cenozoic sequence of the peninsula consists of the Hayama, Miura, Kazusa and Sagami Groups and Alluvial sediments in ascending order. Reinvestigation was carried out by the author on the stratigraphic relationships among and within the groups, and on their tectonics in the Miura Peninsula. In the present paper, the following three themes are described; (1) the history of the geological studies of the Miura Peninsula, (2) the geologic outline of the peninsula, (3) the stratigraphy of the Hayama Group and the igneous rocks associated with the group. The Hayama Group, that is Early to Middle Miocene in age, is lithologically divided into four formations and one unit of olistostrome: namely, the Morito Formation; Abuzuru Formation including Tateishi Tuff Member that is considerd to result from pyroclastic flow deposits; Ōyama Formation; Kinugasa Muddy Olistostrome; and Yabe Formation containing Sakaguchi Tuffaceous Sandstone Member and Koyabe Tuffaceous Sandstone and Siltstone Member in ascending order. Some ultrabasic rocks are described petrographically, EPMA analysis of the minerals is shown. The author points out that the Kinugasa Muddy Olistostrome was possibly derived mostly from the Morito Formation, and partly from the Abuzuru Formation by gravity transportation of both the formations, and that most of the ultrabasic bodies and some of the basalt bodies are olistoliths respectively in the Kinugasa Muddy Olistostrome.
著者
江藤 哲人 松田 恵里 伊藤 憲和
出版者
The Sedimentological Society of Japan
雑誌
堆積学研究 (ISSN:1342310X)
巻号頁・発行日
vol.53, no.53, pp.17-27, 2001-07-25 (Released:2010-05-27)
参考文献数
30
被引用文献数
2

房総半島中部西端部の中部更新統長浜砂礫層および三浦半島中部東端部の上部更新統走水礫層の礫は主に中・古生界に由来する古期岩類で構成され, 次いで中新統の緑色凝灰岩類およびそれに随伴する火成岩類で構成される. そのほか, 第三系堆積岩起源の礫が少量含まれる. 中期~後期更新世の古地理などから判断して, 古期岩類の礫は主として関東山地に, 緑色凝灰岩類および火成岩類は主に丹沢山地にそれぞれ由来すると推定される. 両層堆積期に両山地は大量に礫を供給し得る隆起が起こったと推定できる. 両層の礫種組成には明らかな相違が認められ, 走水礫層の古流向と合わせ考えると, 走水礫層の礫を長浜砂礫層に起源するとみなす見解は否定される. 長浜砂礫層の礫種組成には層位的変化が認められ, 一部の層準に目立つ第三系堆積岩起源の礫は嶺岡山地に由来すると推定され, 嶺岡山地の一時的な隆起を示すと考えられる.