Submarine eruption-fed and resedimented pumice-rich facies: the Dogashima Formation (Izu Peninsula, Japan)

Abstract

The NERC and NOC trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner. of 45Submarine eruption-fed and resedimented pumice- andesite breccia restricted to the base of a submarine channel, gradationally overlain by 28 pumice breccia, which is widespread but much thinner and finer in the overbank setting. 29These two breccias share similar mineralogy and crystal composition, and are considered to 30 be co-magmatic, and derived from the destruction of a submarine dome by an explosive, clasts issued from the destruction of a hot lava dome, and pumice clasts formed by a 100 submarine explosive eruption that destroyed the lava dome. 101The Dogashima Formation is also very important because it was deposited in a submarine 102 channel and its overbank, which are well exposed in cross-section. In such island arc settings,

Grain-size distribution of volcaniclastic rocks 2: Characterizing grain size and hydraulic sorting

“…Most samples belong to the Pliocene Dogashima (Izu Peninsula, Japan) and Oligocene Ohanapecosh (Ancestral Cascades, USA) formations (Fiske, 1963;Cashman and Fiske, 1991;Jutzeler, 2012;Jutzeler et al, 2014a;Jutzeler et al, 2014b). Additional samples were collected in the Miocene Manukau Subgroup (Northland, New Zealand; Allen et al, 2007;Jutzeler, 2012) and in the Quaternary Sierra la Primavera caldera (Jalisco State, Mexico; Clough et al, 1981).…”

“…Results of facies analysis (Jutzeler, 2012;Jutzeler et al, 2014a;Jutzeler et al, 2014b) are used to test whether proportional volume and grain size distribution of coarse (>2 mm) clasts in graded volcaniclastic beds indicate specific types of transport and depositional processes in a context of submarine volcanism. In particular, we analyze the most likely subaqueous transport mechanisms using the hydraulic equivalence signature in context of deposition from vertical settling, collision-induced rolling and shear rolling, through stratigraphy of thick, graded deposits.…”

“…The matrix-rich, very thick, graded facies (MR-thick) includes examples from the Ohanapecosh Formation, the Dogashima Formation, and the Manukau Subgroup (Jutzeler, 2012;Jutzeler et al, 2014a;Jutzeler et al, 2014b). Typical examples comprise graded beds 57 and 61 in the Chinook Pass section, beds 40 and 42 in the Cayuse Pass section (Chinook Pass Member), and bed B-3 at Cougar Lake (Jutzeler et al, 2014b).…”

“…The matrix-poor, very thick, graded facies (MP-thick) occur in the Dogashima Formation and the Ohanapecosh Formation (Jutzeler et al, 2014a;Jutzeler et al, 2014b). The most typical example is the bed of grey andesite breccia (D2-2) overlain by white pumice breccia (D2-3) in Dogashima 2 (Jutzeler et al, 2014a).…”

“…The most typical example is the bed of grey andesite breccia (D2-2) overlain by white pumice breccia (D2-3) in Dogashima 2 (Jutzeler et al, 2014a). These two clast-supported facies were interpreted to have been simultaneously deposited from a M A N U S C R I P T…”