5:15 PM - 6:30 PM
[SVC28-P07] Formation of N3 member from the younger Ōshima group distributed around the Habu area, southeastern part of Izu-Ōshima Island.
Izu-Ōshima island is an active volcano located at the northernmost point of the Izu-Bonin Arc. In Izu-Ōshima Island, outcrops of lava and volcanic sediments flowing from eruptions of mainly low-alkaline tholeiite series basalts can be seen in many places. In this study, we describe the outcrops and lithology of the area from Habu Port to Ryuozaki in the southeastern part of Izu-Ōshima Island, and examine the activity patterns that formed the Habu Port and Ryuozaki area.
The volcanic ejecta exposed on the sea cliffs distributed from the Ryuozaki to the Habu area can be classified into the Ryuozaki Lava, the Ryuozaki layer, the Suribachi layer, the M layer, the Habu lava and the Habu breccia layer.
Based on the stratigraphic sequence of each layer and the characteristics of the rock fragments collected, it is considered that the activities from the northern part of Habu Port to the Ryuozaki area occurred in the following order: 1) eruption of the Ryuozaki lava, which is the basement rock, 2) formation of the Ryuozaki layer by magmatic steam explosion off Ryuozaki, 3) activities of the Suribachi layer and the M layer, 4) eruption of the Habu lava, and 5) magmatic steam explosion (formation of the Habu Conglomerate layer) caused by the contact of the Habu lava with seawater. 5) magma generated by the contact of Habu lava with seawater, and steam explosion (formation of the Habu breccia layer).
The volcanic ejecta exposed on the sea cliffs distributed from the Ryuozaki to the Habu area can be classified into the Ryuozaki Lava, the Ryuozaki layer, the Suribachi layer, the M layer, the Habu lava and the Habu breccia layer.
Based on the stratigraphic sequence of each layer and the characteristics of the rock fragments collected, it is considered that the activities from the northern part of Habu Port to the Ryuozaki area occurred in the following order: 1) eruption of the Ryuozaki lava, which is the basement rock, 2) formation of the Ryuozaki layer by magmatic steam explosion off Ryuozaki, 3) activities of the Suribachi layer and the M layer, 4) eruption of the Habu lava, and 5) magmatic steam explosion (formation of the Habu Conglomerate layer) caused by the contact of the Habu lava with seawater. 5) magma generated by the contact of Habu lava with seawater, and steam explosion (formation of the Habu breccia layer).