Distribution of Volcanic Ash Layers and Turbidites in the North Pacific

Horn, D. R.; Delach, M. N.; Horn, B. M.

doi:10.1130/0016-7606(1969)80[1715:dovala]2.0.co;2

Cited by 54 publications

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“…They are very light gray or light brownish gray (the "white" ash of Horn et al, 1969). Beds thinner than this evidently are dispersed beyond visual recognition by burrowing organisms, but may show up as spikes in glass content in smear slides (Shipboard Scientific Party, 1991).…”

Section: Setting and Summary Of Coring Resultsmentioning

confidence: 99%

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Volcanic Ash and Pumice at Shatsky Rise: Sources, Mechanisms of Transport, and Bearing on Atmospheric Circulation

Natland¹

1993

Proceedings of the Ocean Drilling Program

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Air-fall volcanic ash and pumice were recovered from 22 intervals in upper Miocene-Pleistocene nannofossil oozes cored in Hole 8IOC on Shatsky Rise, northwest Pacific. Shatsky Rise is near the eastern limit of ash falls produced by explosive volcanism in arc systems in northern Japan and the Kuriles, more than 1600 km away. Electron probe analyses establish that the ash beds and pumice pebbles are andesitic to rhyolitic in composition, and belong to both tholeiitic and high-alumina lineages similar to tephra from Japanese volcanoes. High-speed winds in the polar-front and subtropical jets are evidently what propelled the ash for such a distance. The pumice arrived by flotation, driven from the same directions by winds, waves, and currents. It is not ice-rafted debris from the north. One thick pumice bed probably was deposited when a large pumice mat passed over Shatsky Rise.Far more abundant ash occurs in sediments cored at DSDP Sites 578 through 580, about 500 km west of Shatsky Rise. Most of the ash and pumice at Shatsky Rise can be correlated with specific ash beds at 1, 2, or all 3 of these sites by interpolating to precisely determined magnetic reversal sequences in the cores. Most of the correlations are to thick ash layers (5.7 ±3.0 cm) at one or more sites. These must represent extremely large eruptions that spread ash over very wide areas. Whereas several of the thicker correlative ashes fell from elongate east-trending plumes directed from central Japan, the majority of them-dating from about 2 Ma-came from the North Honshu and Kurile arc systems to the northwest. This direction probably was in response to both long-term and seasonal fluctuations in the location and velocity of the polar-front jet, and to more vigorous winter storm fronts originating over glaciated Siberia.

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Section: Setting and Summary Of Coring Resultsmentioning

confidence: 99%

“…The generally wide distribution of Pleistocene-Holocene ash east of Japan was first noted from piston cores (Ninkovich et al, 1966;Horn et al, 1969;Hays and Ninkovich, 1970). Ninkovich and Donn (1976) cited both climatic and volcanological factors for the dispersal of Pleistocene-Holocene ash east of Japan.…”

Section: Introductionmentioning

confidence: 99%

Volcanic Ash and Pumice at Shatsky Rise: Sources, Mechanisms of Transport, and Bearing on Atmospheric Circulation

Natland¹

1993

Proceedings of the Ocean Drilling Program

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“…The color of the shards can be indicative of its composition: colorless shards being silicic and deep brown shards being mafic in composition (Horn et al, 1969;Mascarenhas-Pereira et al, 2006). The shape of volcanic glass is influenced by many variables, including temperature, pressure and composition (Izett, 1981).…”

Section: Microscopic Characteristics Of the Ashesmentioning

confidence: 99%

Nature, source and composition of volcanic ash in surficial sediments around the Zhongsha Islands

Yan

Shi

Wang

2008

J. Ocean Univ. China

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Volcanic detrital sediments are a unique indicator for reconstructing the petrogenetic evolution of submarine volcanic terrains. Volcanic ash in surficial sediments around the Zhongsha Islands includes three kinds of volcanogenic detritus, i.e., brown volcanic glass, colorless volcanic glass and volcanic scoria. The major element characteristics show that bimodal volcanic activity may have taken place in the northern margin of the South China Sea, with brown volcanic glass and colorless volcanic glass representing the mafic end-member and felsic end-member, respectively. Fractional crystallization is the main process for magma evolution. The nature of the volcanic activity implies that the origin of volcanic activity was related to extensional tectonic settings, which is corresponding to an extensional geodynamic setting in the Xisha Trench, and supports the notion, which is based on geophysical data and petrology, that there may exist a mantle plume around the Hainan Island.

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“…Piston cores were recovered from the Aleutian Trench nearly two decades ago [ 10], but the sand layers from the cores were not analyzed for mineralogy in a quantitative manner. This paper summarizes the results of recent point counts and describes longitudinal variations in detrital mineralogy.…”

Section: Introductionmentioning

confidence: 99%

Transverse infilling of the central Aleutian Trench by unconfined turbidity currents

Underwood¹

1986

Geo-Marine Letters

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Holocene sand layers cored from the central Aleutian Trench are dominated by volcaniclastic debris, and the only likely source is the central Aleutian volcanic arc. This creates something of an enigma because bathymetric obstructions seemingly prevent direct delivery of sediment via transverse canyons or channels. Turbidity Currents are funneled through submarine canyons on the upper trench slope, but the flows become unconfined as they cross the midslope Aleutian Terrace. Evidently, the turbid flows maintain high enough velocities to climb over the trench-slope break; acceleration down the lower trench slope then allows forearc bypassing to occur without the aid of through-going channels.

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Distribution of Volcanic Ash Layers and Turbidites in the North Pacific

Cited by 54 publications

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Volcanic Ash and Pumice at Shatsky Rise: Sources, Mechanisms of Transport, and Bearing on Atmospheric Circulation

Volcanic Ash and Pumice at Shatsky Rise: Sources, Mechanisms of Transport, and Bearing on Atmospheric Circulation

Nature, source and composition of volcanic ash in surficial sediments around the Zhongsha Islands

Transverse infilling of the central Aleutian Trench by unconfined turbidity currents

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