Provenance of plutonic detritus in cover sandstones of Nicoya Complex, Costa Rica: Cretaceous unroofing history of a Mesozoic ophiolite sequence

Research Article| July 01, 2003 Provenance of plutonic detritus in cover sandstones of Nicoya Complex, Costa Rica: Cretaceous unroofing history of a Mesozoic ophiolite sequence Claudio Calvo Claudio Calvo 1Anna-Peters-Strasse 51/C, 70597 Stuttgart, Germany Search for other works by this author on: GSW Google Scholar Author and Article Information Claudio Calvo 1Anna-Peters-Strasse 51/C, 70597 Stuttgart, Germany Publisher: Geological Society of America Received: 30 Apr 2001 Revision Received: 24 Sep 2002 Accepted: 12 Nov 2002 First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2003) 115 (7): 832–844. https://doi.org/10.1130/0016-7606(2003)115<0832:POPDIC>2.0.CO;2 Article history Received: 30 Apr 2001 Revision Received: 24 Sep 2002 Accepted: 12 Nov 2002 First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Claudio Calvo; Provenance of plutonic detritus in cover sandstones of Nicoya Complex, Costa Rica: Cretaceous unroofing history of a Mesozoic ophiolite sequence. GSA Bulletin 2003;; 115 (7): 832–844. doi: https://doi.org/10.1130/0016-7606(2003)115<0832:POPDIC>2.0.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 SocietyGSA Bulletin Search Advanced Search Abstract This study presents new petrologic and sedimentologic data from northwestern Costa Rica concerning the provenance of Cretaceous forearc sandstones that contain plutonic detritus. Plutonic rock fragments are important accessory particles in pyroxene-bearing sandstones overlying the ophiolite named the Nicoya Complex. Through the use of modal analysis of the framework grains, I studied three sandstone suites of the El Viejo and Rivas Formations that include both shallow- and deep-water deposits, ranging from late Campanian to Maastrichtian in age. In terms of primary framework components, the sandstones resemble those derived from magmatic arcs. Two modal parameters are introduced to evaluate detrital plutonic contributions and affinity of source rocks: the ratio of plutonic to total lithic fragments [(Lp + iQF)/Lt], and the ratio of uralitized pyroxene to total pyroxene grains (uralPx/Px). Modal values for (Lp + iQF)/Lt indicate that plutonic fragments comprise up to 9% of total lithic fragments. A strong correlation between these two parameters suggests that uralitized pyroxene grains were also derived from intrusive rocks of probably basic and intermediate compositions. In particular, significant concentrations of lithic fragments exhibiting micrographic textures and uralitized pyroxene grains are interpreted to have been derived predominantly from eroded plagiogranites. Sandstone suites containing plutonic detritus signal an unroofing of deeper levels of the Mesozoic ophiolitic sequence as a consequence of strong uplift of the Costa Rican arc in late Senonian time. This tectonic event began in the Campanian at ca. 75 Ma, ∼9 m.y. after the intrusive magmatic activity on Nicoya Peninsula, and is consistent with the onset of the Laramide orogeny. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.