Late Cenozoic tephrostratigraphy offshore the southern Central American volcanic arc; 2, Implications for magma production rates and subduction erosion

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doi: 10.1002/2016GC006504
Author(s): Schindlbeck, J. C.; Kutterolf, S.; Freundt, A.; Straub, S. M.; Vannucchi, P.; Alvarado, Guillermo E.
Author Affiliation(s): Primary:
GEOMAR-Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Other:
Lamont-Doherty Earth Observatory, United States
University of London, United Kingdom
Instituto Costarricense de Electricidad, Costa Rica
Volume Title: Geochemistry, Geophysics, Geosystems - G<sup>3</sup>
Source: Geochemistry, Geophysics, Geosystems - G>3`, 17(11), p.4585-4604. Publisher: American Geophysical Union and The Geochemical Society, United States. ISSN: 1525-2027
Note: In English. 104 refs.; illus., incl. 1 table, sketch map
Summary: Pacific drill sites offshore Central America provide the unique opportunity to study the evolution of large explosive volcanism and the geotectonic evolution of the continental margin back into the Neogene. The temporal distribution of tephra layers established by tephrochonostratigraphy in Part 1 indicates a nearly continuous highly explosive eruption record for the Costa Rican and the Nicaraguan volcanic arc within the last 8 Myr. The widely distributed marine tephra layers comprise the major fraction of the respective erupted tephra volumes and masses thus providing insights into regional and temporal variations of large-magnitude explosive eruptions along the southern Central American Volcanic Arc (CAVA). We observe three pulses of enhanced explosive volcanism between 0 and 1 Ma at the Cordillera Central, between 1 and 2 Ma at the Guanacaste and at >3 Ma at the Western Nicaragua segments. Averaged over the long-term the minimum erupted magma flux (per unit arc length) is ∼0.017 g/ms. Tephra ages, constrained by Ar-Ar dating and by correlation with dated terrestrial tephras, yield time-variable accumulation rates of the intercalated pelagic sediments with four prominent phases of peak sedimentation rates that relate to tectonic processes of subduction erosion. The peak rate at >2.3 Ma near Osa particularly relates to initial Cocos Ridge subduction which began at 2.91 ± 0.23 Ma as inferred by the 1.5 Myr delayed appearance of the OIB geochemical signal in tephras from Barva volcano at 1.42 Ma. Subsequent tectonic re-arrangements probably involved crustal extension on the Guanacaste segment that favored the 2-1 Ma period of unusually massive rhyolite production. Abstract Copyright (2016), . American Geophysical Union. All Rights Reserved.
Year of Publication: 2016
Research Program: DSDP Deep Sea Drilling Project
IODP Integrated Ocean Drilling Program
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Caribbean Plate; Caribbean region; Cenozoic; Central America; Central American volcanic arc; Central Cordillera; Chemical composition; Cocos Plate; Cocos Ridge; Costa Rica; Costa Rica Seismogenesis Project; DSDP Site 565; Deep Sea Drilling Project; East Pacific; Erosion; Expedition 334; Expedition 344; Explosive eruptions; Geophysical methods; Geophysical profiles; Geophysical surveys; Guanacaste Costa Rica; Guatemala Basin; IODP Site U1378; IODP Site U1380; IODP Site U1381; IODP Site U1412; IODP Site U1413; IODP Site U1414; IPOD; Igneous rocks; Integrated Ocean Drilling Program; Leg 138; Leg 170; Leg 202; Leg 205; Leg 84; Magmas; Middle America Trench; Nearshore sedimentation; Neogene; Nicaragua; Nicoya Peninsula; North Pacific; Northeast Pacific; ODP Site 1039; ODP Site 1040; ODP Site 1041; ODP Site 1241; ODP Site 1242; ODP Site 1253; ODP Site 1254; ODP Site 1255; ODP Site 1256; ODP Site 844; Ocean Drilling Program; Ocean floors; Osa Peninsula; Pacific Ocean; Plate tectonics; Pyroclastics; Quaternary; Rhyolites; Sedimentation; Sedimentation rates; Seismic methods; Seismic profiles; Subduction; Surveys; Tephrostratigraphy; Tertiary; Upper Cenozoic; Volcanic belts; Volcanic rocks; Volcanism
Coordinates: N050000 N130000 W0820000 W0920000
Record ID: 2017025613
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from John Wiley & Sons, Chichester, United Kingdom, Reference includes data supplied by, and/or abstract, Copyright, American Geophysical Union