On-and offshore tephrostratigraphy and -chronology of the southern Central American Volcanic Arc (CAVA)

Author(s): Schindlbeck, Julie Christin; Kutterolf, Steffen; Hemming, Sidney R.; Wang, Kuo-Lung
Author Affiliation(s): Primary:
GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
Other:
Lamont-Doherty Earth Observatory, United States
Academia Sinica, Taiwan
Volume Title: AGU 2015 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2015; American Geophysical Union 2015 fall meeting, San Francisco, CA, Dec. 14-18, 2015. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: Including the recently drilled CRISP sites (IODP Exp. 334&344) the deep sea drilling programs have produced 69 drill holes at 29 Sites during 9 Legs at the Central American convergent margin, where the Cocos plate subducts beneath the Caribbean plate. The CAVA produced numerous plinian eruptions in the past. Although abundant in the marine sediments, information and data regarding large late Cenozoic explosive eruptions from Costa Rica, Nicaragua, Honduras, El Salvador, and Guatemala remain very sparse and discontinuous on land. We have established a tephrostratigraphy from recent through Miocene times from the unique archive of ODP/IODP sites offshore Central America in which we identify tephra source regions by geochemical fingerprinting using major and trace element glass shard compositions. Here we present first order correlations of -∼500 tephra layers between multiple holes at a single site as well as between multiple sites. We identified ashes supporting Costa Rican (∼130), Nicaraguan (17) and Guatemalan (27) sources as well as ∼150 tephra layers from the Galapagos hotspot. Within our marine record we also identified well-known marker beds such as the Los Chocoyos tephra from Atitlan Caldera in Guatemala and the Tiribi Tuff from Costa Rica but also correlations to 15 distinct deposits from known Costa Rican and Nicaraguan eruptions within the last 4.1 Ma. These correlations, together with new radiometric age dates, provide the base for an improved tephrochronostratigraphy in this region. Finally, the new marine record of explosive volcanism offshore southern CAVA provides insights into the eruptive history of long-living volcanic complexes (e.g., Barva, Costa Rica) and into the distribution and frequency of large explosive eruptions from the Galapagos hotspot. The integrated approach of Ar/Ar age dating, correlations with on land deposits from CAVA, biostratigraphic ages and sediment accumulation rates improved the age models for the drilling sites.
Year of Publication: 2015
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 07 Marine Geology and Oceanography; Costa Rica Seismogenesis Project; East Pacific; Expedition 334; Expedition 344; Geochronology; Igneous rocks; Integrated Ocean Drilling Program; North Pacific; Northeast Pacific; Pacific Ocean; Pyroclastics; Volcanic rocks
Coordinates: N082400 N084200 W0840000 W0841100
N082542 N084430 W0840423 W0841335
Record ID: 2016106233
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data supplied by, and/or abstract, Copyright, American Geophysical Union, Washington, DC, United States