Large scale explosive eruptions of Akan volcano, eastern Hokkaido, Japan: A geological and petrological case study for establishing tephro-stratigraphy and -chronology around a caldera cluster
Large scale explosive eruptions of Akan volcano, eastern Hokkaido, Japan: A geological and petrological case study for establishing tephro-stratigraphy and -chronology around a caldera cluster
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日本北海道东部阿寒火山大规模喷发：围绕火山口群建立火山地层学和年代学的地质和岩石学案例研究
DOI：
10.1016/j.quaint.2015.07.058
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发表时间：
2016
影响因子：
2.2
通讯作者：
Mitsuhiro Nakagawa
中科院分区：
文献类型：
--
作者：
Takeshi Hasegawa;Mitsuhiro Nakagawa
阿寒火山位于千岛岛弧南部的北海道东部，占据一个矩形破火山口（24 x 13公里），具有悠久（1.7-0.2 Ma）且复杂的历史。本文结合火山灰地层学、火山灰年代学、岩石学和地球化学证据，阐明了该破火山口的喷发历史和演化。Akan破火山口的火山碎屑沉积物被划分为至少40个“喷发单元”，由古土壤分隔，构成17个“喷发组”（Ak 1至Ak 17，按地层降序排列），这些组在岩石学上是不同的，并由较长休眠期的指标（如厚（>30 cm）的古土壤和角度不整合面）分隔。大多数喷发组的估计体积小于10 km 3致密岩石当量，四个组（Ak 2，Ak 4，Ak 7和Ak 13）较大。Ak 2群面积最大，超过50 km 3。Akan破火山口的火山碎屑沉积物与邻近的Kutcharo破火山口的火山碎屑沉积物和来自北海道中部的远距离空气降落灰层相互交错，这表明破火山口形成期在北海道中部和东部重叠。这些外来沉积物的放射性年龄介于1.46 ~ 0.21 Ma之间，表明阿坎火山的破火山口喷发持续了超过100万年，平均岩浆排放速率约为10− 1 km 3/kyr。阿坎火山口火山碎屑岩中的幼年材料主要由隐晶质、二辉石英安岩到流纹岩组成。它们的特点是K2 O组成范围宽（0.8-2.8重量%）在SiO2组成的窄范围内（67-73重量%）。SiO2与K2 O表明，每个喷发群是一个独特的，短暂的岩浆系统，而不是一个单一的长期岩浆系统的产品。这些岩浆系统似乎是在破火山口下连续生成和喷发的，持续时间超过100万年。因此，每个岩浆系统似乎代表了一个相对较短的活动期，它们在下一个岩浆系统之前被相对较长的休眠期隔开。特别是，400 kyr的长期休眠之前爆发组AK 2，其中包括最庞大的和成分变化的岩浆。
Akan volcano, in eastern Hokkaido in the southern Kurile arc, occupies a rectangular caldera (24 × 13 km) with a long (1.7–0.2 Ma) and complex history. This paper combines tephrostratigraphy, tephrochronology, and petrological and geochemical evidence to elucidate the eruptive history and evolution of the caldera. Pyroclastic deposits from Akan caldera are divided into at least 40 “eruptive units”, separated by paleosols, that constitute 17 “eruptive groups” (Ak1 to Ak17, in descending stratigraphic order) that are petrologically distinct and separated by indicators of longer dormancy periods such as thick (>30 cm) paleosols and angular unconformities. The estimated volumes of most eruptive groups are less than 10 km3dense rock equivalent, and four groups (Ak2, Ak4, Ak7, and Ak13) are larger. Group Ak2, exceeding 50 km3, is the largest. Pyroclastic deposits from Akan caldera are intercalated with pyroclastic deposits from the adjacent Kutcharo caldera and distal air-fall ash layers from central Hokkaido, suggesting that caldera-forming episodes overlapped in central and eastern Hokkaido. Radiometric ages from these exotic deposits range from 1.46 to 0.21 Ma, indicating that caldera-forming eruptions occurred at Akan volcano for more than 1 million years at an average magma discharge rate of approximately 10−1km3/kyr. Juvenile materials in Akan caldera pyroclastics consist of dominantly aphyric, two-pyroxene dacite to rhyolite. They are characterized by a wide range of K2O compositions (0.8–2.8 wt.%) within a narrow range of SiO2compositions (67–73 wt.%). Plots of SiO2vs. K2O suggest that each eruptive group is the product of a distinct, ephemeral magma system rather than a single long-lived magma system. These magma systems appear to have been generated and erupted successively beneath the caldera for more than 1 million years. Each magma system thus appears to represent a relatively short period of activity, and they were separated by relatively long dormancy periods before the next magma system. In particular, a long dormancy of 400 kyr preceded eruptive group Ak2, which consists of the most voluminous and compositionally varied silicic magmas.
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十胜平原的构造发育——带广盆地与幕别高原的分异
DOI：
10.4116/jaqua.23.233
发表时间：
1985
期刊：
The Quaternary Research (daiyonki-kenkyu)
影响因子：
--
作者：
Masaru Matsui;Itsumi Matsuzawa
通讯作者：
Itsumi Matsuzawa
索马熔岩的镁铁质岩浆与火山口形成的大量长英质岩浆之间的岩石成因关系：以日本北海道东部阿寒火山田为例
影响因子：
0.7
作者：
Y. Ikeda
通讯作者：
Y. Ikeda
与千岛海沟倾斜的阿坎-希雷托科火山链的 K-Ar 年龄：对火山活动的构造控制的影响
影响因子：
1.5
作者：
Y. Goto;Atsushi Funayama;Nobuo Gouchi;T. Itaya
通讯作者：
T. Itaya
日本北部北海道地区的第四纪火山灰研究
DOI：
10.4116/jaqua.30.379
发表时间：
1991
期刊：
The Quaternary Research (daiyonki-kenkyu)
影响因子：
--
作者：
K. Okumura
通讯作者：
K. Okumura
异常活跃的流纹岩岩浆系统的晚第四纪演化：新西兰陶波火山中心
影响因子：
2.7
作者：
Andrew N. Sutton;S. Blake;C. Wilson;B. Charlier
通讯作者：
B. Charlier