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Main Authors: Melson, William G, O'Hearn, Timothy, Fredriksson, Kurt
Format: Dataset Open Access
Language:en
Published: PANGAEA 1988
Subjects:
Online Access:https://doi.org/10.1594/PANGAEA.760741
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author Melson, William G
O'Hearn, Timothy
Fredriksson, Kurt
author_facet Melson, William G
O'Hearn, Timothy
Fredriksson, Kurt
collection Datos científicos de ciencias marinas y ambientales
contents Lower Miocene basaltic glass spherules from DSDP Site 32 pelagic sediments in the eastern Pacific are compositionally diverse, and new analyses and interpretations have been added to those of earlier workers. The spherules are of titanian ferrobasalt which is compositionally similar to highly evolved abyssal basalts and to some oceanic island eruptives, and they were most likely shaped during intense lava fountaining during a number of separate eruptions. These eruptions tapped distinct but related magma batches in terms, for example, of distinctively high TiO2 and FeO* contents. Their age overlaps that of some of the eruptions of the Columbia River Plateau Basalts, but they are compositionally distinct from most of the latter basalts. Although about 15 m.y. old, they show little alteration. The low chlorine and sulfur contents compared to those of abyssal ferrobasalts are consistent with degassing prior to quenching during subaerial eruptions, and rule out production of the spherules by submarine fountaining. Lava fountaining alone is insufficient to account for the distance of about 100 km from even the closest possible seamount source. Instead, large phreatomagmatic eruption columns reaching at least 15 km and including lava fountaining immediately after the initial explosion are required. Alternatively, and deemed less likely, is their deposition by turbidites derived from Pioneer Seamount.
format Dataset Open Access
id pangaea_https___doi_org_10_1594_PANGAEA_760741
institution PANGAEA
language en
publishDate 1988
publisher PANGAEA
record_format pangaea
spellingShingle Spherules and basement analyses from DSDP Hole 5-32
Melson, William G
O'Hearn, Timothy
Fredriksson, Kurt
5-32; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Leg5; North Pacific/PLAIN
Lower Miocene basaltic glass spherules from DSDP Site 32 pelagic sediments in the eastern Pacific are compositionally diverse, and new analyses and interpretations have been added to those of earlier workers. The spherules are of titanian ferrobasalt which is compositionally similar to highly evolved abyssal basalts and to some oceanic island eruptives, and they were most likely shaped during intense lava fountaining during a number of separate eruptions. These eruptions tapped distinct but related magma batches in terms, for example, of distinctively high TiO2 and FeO* contents. Their age overlaps that of some of the eruptions of the Columbia River Plateau Basalts, but they are compositionally distinct from most of the latter basalts. Although about 15 m.y. old, they show little alteration. The low chlorine and sulfur contents compared to those of abyssal ferrobasalts are consistent with degassing prior to quenching during subaerial eruptions, and rule out production of the spherules by submarine fountaining. Lava fountaining alone is insufficient to account for the distance of about 100 km from even the closest possible seamount source. Instead, large phreatomagmatic eruption columns reaching at least 15 km and including lava fountaining immediately after the initial explosion are required. Alternatively, and deemed less likely, is their deposition by turbidites derived from Pioneer Seamount.
title Spherules and basement analyses from DSDP Hole 5-32
topic 5-32; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Leg5; North Pacific/PLAIN
url https://doi.org/10.1594/PANGAEA.760741