Quaternary Tephra Studies in the Kanto-Chubu Districts, Central Japan
Quaternary Tephra Studies in the Kanto-Chubu Districts, Central Japan
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日本中部关东中部地区的第四纪火山灰研究
DOI：
10.4116/jaqua.30.361
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
K. Hayatsu
中科院分区：
文献类型：
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作者：
Takehiko Suzuki;K. Hayatsu
本文的目的是双重的。一是回顾日本中部关东和中部地区的火山灰研究，二是找出仍有待研究的重要问题。在这些地区，有马尼火山灰层、保存完好的河流和海洋阶地以及冰川沉积物，这些沉积物在地层上与火山灰岩有关。这种有利的条件刺激了第四纪研究人员和火山学家，因此在关东中部地区进行了许多火山灰研究。该地区的火山灰研究比日本任何其他地区都更加先进。更新世晚期的火山地层学已相对完善（图1）。这是许多研究的结果，从 20 世纪 60 年代关东壤土研究小组 (1965) 期间进行的研究到目前正在进行的研究。特别是，由 MACHIDA 和 ARAI (1976) 在 1970 年代对 AT 灰的工作发起的对日本各地广泛分布的火山灰的研究，有助于确定遥远的火山灰层之间的地层关系。现在有必要构建关东地区中更新世火山灰年代学。广泛分布的火山灰应该发挥重要作用。在这里，作者提供了最近发现的几种广泛分布的火山灰的新数据。大町APm火山灰层（A1Pm-A5Pm）发源于300-350ka的飞驒山脉，分布广泛，从中部北部到关东北部。 A4Pm 和 A5Pm 夹着主要由气泡壁玻璃碎片组成的玻璃灰层，被鉴定为来自八岳火山东麓的 Nuka 1 灰。该玻璃灰层可能与九州南部的角东火山碎屑流沉积物（Kt-U）有关。此外，在 A5Pm 上方还发现了另一个玻璃灰层，真田灰 (SnA)。在关东南部的大矶山上发现了一种类似于 SnA 的火山灰，被称为米色灰，估计年龄为 240 年前。 SnA 和米色灰与九州南部的鸟浜火山碎屑流沉积物 (Th) 相似，表明它们之间存在相关性。
The purpose of this paper is twofold. One is to review tephra studies in the Kanto and Chubu areas of central Japan, and the other is to identify important problems that remain to be studied. In these areas, there are marny tephra layers, well preserved fluvial and marine terraces, and glacial deposits, that are stratigraphically related to the tephras. Such favorable conditions have stimulated Quaternary researchers and volcanologists, and consequently there have been many tephra studies done in the Kanto-Chubu areas. Tephra study is more advanced in this region than in any other areas of Japan.The tephrostratigraphy of the late Pleistocene is relatively well established (Figure 1). This results from many studies, ranging from those carried out in the 1960's during the time of the KANTO LOAM RESEARCH GROUP (1965), to those being carried out at present. In particular, studies of widespread tephras throughout Japan, initiated by MACHIDA and ARAI's (1976) work on the AT ash in the 1970's, contributed to the determination of stratigraphic relations between distant tephra layers.Now it is necessary to construct a middle Pleistocene tephrochronology of the Kanto area. Widespread tephras should play a significant role. Here, the authors present new data on several recently discovered widespread tephras. The Omachi APm tephra beds (A1Pm-A5Pm), originating in the Hida Mountains at 300-350ka, are widely distributed, from northern Chubu to the north Kanto. A4Pm and A5Pm sandwich a vitric ash layer composed mainly of bubble-walled glass shards, identified as Nuka 1 Ash from the eastern foot of Yatsugatake Volcano. This vitric ash layer probably correlates with the Kakuto pyroclastic flow deposit (Kt-U) in southern Kyushu. Moreover, another vitric ash layer, the Sanada Ash (SnA), is found above A5Pm. A tephra similar to SnA is found on the Oiso Hills in the southern Kanto, and is called the Beige Ash, with an estimated age of 240ka. SnA and the Beige Ash are similar to the Torihama pyroclastic flow deposit (Th) in south Kyushu, suggesting their correlation.