Magmatic and geotectonic significance of Santa Elena Peninsula, Costa Rica

Authors

  • E. GAZEL Escuela Centroamericana de Geología, Universidad de Costa Rica
  • P. DENYER Escuela Centroamericana de Geología, Universidad de Costa Rica
  • P. O. BAUMGARTNER Institut de Géologie et Paléontologie, Université de Lausanne

DOI:

https://doi.org/10.1344/105.000000365

Keywords:

Santa Elena Peninsula, Oceanic assemblages, Ultramafic Complex, Geochemistry, Accretionary complex

Abstract

We present a new integrated interpretation of the geochemistry and geotectonic significance of the Santa Elena Peninsula, which is divided in three units: 1) an overthrust allocthonous unit of ultramafic and mafic rocks, the Santa Elena Nappe; 2) an autochthonous basaltic sedimentary suite, resting immediately below the overthrust, the Santa Rosa Accretionary Complex; and 3) Islas Murciélago pillow and massive basaltic flows. In the Santa Elena Nappe three petrological affinities have been recognized: 1) the ultramafic complex, that corresponds to depleted (MORB-like) mantle serpentinizated peridotites, with very low TiO2 and high Ni and Cr; 2) the pegmatitic gabbros, layered gabbros and plagiogranites and basaltic dikes with low TiO2 (<0.89%) contents and high LREE depletions; and 3) the doleritic dykes with higher TiO2 (>0.89%). These mafic associations have geochemical signatures that suggest an island arc origin and petrographic evidences of low grade metamorphism and hydrothermal alteration. The Santa Rosa Accretionary Complex includes pelagic and volcanoclastic sediments, tuffs and alkaline magmatic rocks, originated by low degree melting of enrichment OIB mantle source, and probably related with seamount portions incorporated into the accretionary prism. Islas Murciélago pillow and massive basalts show no clear structural relationship with the rest of the units, but are geochemically similar to the dolerites of the Santa Elena Nappe. Sr, Nd, and Pb isotopic ratios of the Santa Elena Nappe and the Santa Elena Accretionary Complex samples do not correspond to the Galapagos Mantle array, and have different mantle reservoirs and geochemical characteristics than the Nicoya Complex.

References

Alvarado, G.E., Denyer, P., 1998. Implications for the Caribbean Region of the high-Mg volcanic rocks in the Costa Rica ophiolite complexes: The case of the Tortugal, komatiiticlike suite. Zentralblatt für Geologie und Palaeontologie, I (3-6), 409-429.

Appel, H., Wörner, G., Alvarado, G., Rundle, C., Kussmaul, S., 1994. Age relations in igneous rocks from Costa Rica. Stuttgart, Profil, 7, 63-69.

Arias, M., 2002. Petrografía y geoquímica de las rocas del Complejo Ígneo Estratificado de Bahía Nancite y su relación con los filones basálticos, península de Santa Elena, Costa Rica. Licenciature thesis. Universidad de Costa Rica. San José, 94 pp.

Baumgartner, P.O., 1987. Tectónica y sedimentación del Cretácico superior en la zona pacífica de Costa Rica (América Central). In: Barbarin, J.M., Gursky, H.-J., Meiburg, P. (eds.). El Cretácico de México y América Central. Facultad de Ciencias de la Tierra, Universidad Autónoma de Nuevo León, Linares (México), Actas, 2, 251-260.

Beccaluva, L., Chinchilla-Chaves, A.L., Coltorti, M., Giunta, G., Siena, F., Vaccaro, C., 1999. Petrological and structural significance of the Santa Elena-Nicoya Ophiolitic Complex in Costa Rica and geodynamic implications. European Journal of Mineralogy, 11, 1091-1107.

Bellon, H., Tournon, J., 1978. Contribution de la geochronometrie K-Ar à l’étudi du magmatism de Costa Rica, Amerique Central. Bulletin de la Société Géologique de France, 6(7), 955-959.

Castillo, P., Batiza, R., Vanco, D., Malavassi, E., Barquero, J., Fernández, E., 1988. Anomalously young volcanoes on old hot-spot traces: Geology and petrology of Cocos Island. Geological Society of America Bulletin, 100, 1400-1414.

Dengo, G., 1962. Tectonic-igneous sequence in Costa Rica. In: Engel, A.E.J., James, H.J., Leonard, B.F. (eds). A volume to honor A. F. Budington. Geological Society of America Special Volume, 133-161.

Dengo, G., 1973. Estructura geológica, historia tectónica y morfología de América Central. México. Centro Regional de Ayuda Técnica-AID, 52 pp.

DeWever, P., Azéma, J, Tournon, J., Desmet, A., 1985. Découverte de matériel océanique du Lias-Dogger inférieur dans la péninsule de Santa Elena (Costa Rica, Amérique Centrale). Comptes Rendus de L’Académie des Sciences de Paris, 300(15), 759-764.

Gursky, H.J., 1994. The oldest sedimentary rocks of South Central America: The radiolarian cherts of the Nicoya Ophiolite

Complex (?Early Jurassic to Late Cretaceous). Stuttgart, Profil, 7, 265-277.

Harrison, J.V., 1953. The geology of the Santa Elena peninsula in Costa Rica, Central America. 7th Pacific Congress, New

Zealand, Proceedings, 2, 102-104.

Haskin, L.A., 1984. Petrogenetic modeling: use of rare earth elements. In: Henderson, P. (ed.). Rare Earth Elements Geochemistry. Amsterdam, Elsevier, 115-152.

Hauff, F., Hoernle, K., Schmincke, H.U., Werner, R., 1997. A mid Cretaceous origin for the Galapagos hotspot: volcanological, petrological and geochemical evidence from Costa Rica oceanic crustal fragments. Geologische Rundschau, 86, 141-155.

Hauff, F., Hoernle, K., Bogaard, P., 2000. Age and geochemistry of basaltic complexes in western Costa Rica: Contributions

to the geotectonic evolution of Central America. Geochemistry, Geophysics, Geosystems, 1(5), doi 10.1029/1999-GC000020.

Kuijpers, E., 1980. The geologic history of the Nicoya Ophiolite Complex, Costa Rica, and its geotectonic significance. Tectonophysics, 68, 233-255.

Kussmaul, S., Paniagua, S., Gainsa, J., 1982. Recopilación, clasificación e interpretación petroquímica de las rocas de Costa Rica. Informe Semestral Instituto Geográfico Nacional, 2, 17-79.

Meschede, M., Frisch, W., 1994. Geochemical characteristics of basaltic rocks from the Central American ophiolites. Stuttgart, Profil, 7, 71-85.

Miyashiro, A., 1972. Pressure and temperature conditions and tectonic significance of regional and ocean-floor metamorphism. Tectonophysics, 13(1-4), 141-159.

Pearce, J.A., Harris, N.B.W., Tindle, A.G., 1984. Trace element discrimination diagrams for the tectonic interpretation of granitic rocks. Journal of Petrology, 25, 956-983.

Ragazzi, C., 1996. Petrologia e geologia del Complesso Ofiolitico di Nicoya-St. Elena (Costa Rica). Doctoral thesis. Università degli Studi di Ferrara, 115 pp.

Rogers, R.S., 2003. Jurassic-Recent tectonic and stratigraphic history of the Chortis block of Honduras and Nicaragua (northern Central America). Doctoral thesis. University of Texas, 264 pp.

Schmidt-Effing, R., 1980. Radiolarien der Mittel-Kreide aus dem Santa Elena-Massiv von Costa Rica. Neues Jahrbuch

für Geologie und Paläontologie, 160(2), 241-257.

Sinton, C.W., Duncan, R. A., Denyer, P., 1997. Nicoya península: A single suite of Caribbean oceanic plateau magmas. Journal of Geophysical Research, 102(B7), 15507-15520.

Shervais, J.W., 1982. Ti-V plots and the petrogenesis of modern and ophilitic lavas. Earth and Planetary Science Letters, 59,

-118

Sun, S.S., McDonough, W.F., 1989. Chemical and isotopic systematics of oceanic basalts: Implications for mantle compositions and processes. In: Saunders, A.D., Norry, M.J. (eds.). Magmatism in the ocean basins. Geological Society Special Publication, 42, 313-345.

Tournon, J., 1984. Magmatismes du Mesozoique á l’actuel en Amérique Centrale: L’exemple de Costa Rica, des ophiolites

aux andesites. Doctoral thesis. University Pierre and Marie Curie, Paris, 335 pp.

Tournon, J., 1994. The Santa Elena Peninsula: an ophiolitic nappe and a sedimentary volcanic relative autochthonous. Stuttgart, Profil, 7, 87-96.

Tournon, J., Azéma J., 1980. Sobre la estructura y la petrología del Macizo Ultrabásico de Santa Elena, Provincia de Guanacaste, Costa Rica. Informe Semestral Instituto Geográfico Nacional, 1980(1), 17-34.

Tournon, J., Seyler, M., Astorga, A., 1995. Les peridotites du Rio San Juan (Nicaragua et Costa Rica); jalons possibles d’une suture ultrabasique E-W en Amérique Centrale méridionale. Paris, Comptes Rendus de l’Académie des Sciences, 320(8), 757-764.

Venable, M.E., 1994. A geologic, tectonic, and metallogenic evaluation of Siuna terrane. Doctoral thesis. University of Arizona, 154 pp.

Widberg, H.G.H., 1984. Der Nicoya Komplex, Costa Rica, Zentralamerika: Magmatismus und genese eines polymagmatischen Ophiolith-Komplexes. Münster Forschungsschwerpunkte Geologisch Paläontologisches, 62, 1-123.

Zinder, A., Hart, S.R., 1986. Chemical geodynamics. Annual Reviews of Earth and Planetary Sciences, 14, 493-571.

Downloads

Published

2006-01-11