The 89 Ma Tortugal komatiitic suite, Costa Rica: Implications for a common geological origin of the Caribbean and Eastern Pacific region from a mantle plume

Abstract

Research Article| May 01, 1997 The 89 Ma Tortugal komatiitic suite, Costa Rica: Implications for a common geological origin of the Caribbean and Eastern Pacific region from a mantle plume Guillermo E. Alvarado; Guillermo E. Alvarado 1Instituto Costarricense de Electricidad, Departamento Ingeniería Geológica, Apdo. 10032-1000, Costa Rica Search for other works by this author on: GSW Google Scholar Percy Denyer; Percy Denyer 2Escuela Centroamericana de Geología, Universidad de Costa Rica, Apdo. 35-2060, San José, Costa Rica Search for other works by this author on: GSW Google Scholar Christopher W. Sinton Christopher W. Sinton 3Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island 02882 Search for other works by this author on: GSW Google Scholar Geology (1997) 25 (5): 439–442. https://doi.org/10.1130/0091-7613(1997)025<0439:TMTKSC>2.3.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Guillermo E. Alvarado, Percy Denyer, Christopher W. Sinton; The 89 Ma Tortugal komatiitic suite, Costa Rica: Implications for a common geological origin of the Caribbean and Eastern Pacific region from a mantle plume. Geology 1997;; 25 (5): 439–442. doi: https://doi.org/10.1130/0091-7613(1997)025<0439:TMTKSC>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Komatiites are reported for the first time in the northern part of the Gulf of Nicoya, Costa Rica. These rocks, dated at 89.7 ± 1.4 Ma (Turonian) by 40Ar/39Ar methods, occur as a large, elongated (14 km long, 1.5 km wide) N60°W striking body in the ophiolitic Nicoya Complex. These lavas have high MgO (26%–29%), Ni, and Cr, have high CaO/Al2O3 (0.98–1.08) and moderate Al2O3/TiO2 (5.55–8.44) ratios, and are depleted in Al2O3 (4%–5.5%), K2O (0.02%–0.37%), and TiO2 (0.59%–0.9%). Although these lavas are cumulates, their geochemical composition indicates an origin from a primary komatiitic magma, with a melting temperature of 1700 °C at a depth of 150 km. Similarities in the petrology and age (88–90 Ma) of Gorgona, Curaìao, and Nicoya-Tortugal mafic and ultramafic volcanic rocks suggest that these rocks had a common origin. These occurrences suggest a single hotspot center over a large area of the Caribbean and Eastern Pacific Mesozoic region due to a major thermal anomaly in the mantle, such as a hot, rising, convective plume. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.