Post-Early Cretaceous Mississippi Valley-type Zn-Pb Mineralization in the Bongara Area, Northern Peru: Fluid Evolution and Paleo Flow from Fluid Inclusion Evidence

Abstract

Research Article| January 01, 2009 Post-Early Cretaceous Mississippi Valley-type Zn-Pb Mineralization in the Bongara Area, Northern Peru: Fluid Evolution and Paleo Flow from Fluid Inclusion Evidence N.I. Basuki; N.I. Basuki † 1F. Gordon Smith Fluid Inclusion Lab., Department of Geology, University of Toronto, 22 Russell St., Toronto, Ontario M5S 3B1. *Present address: Department of Geology, Institut Teknologi Bandung (ITB), Ganesha 10, Bandung 40132, Jawa Barat, Indonesia. †Corresponding Author: E-mail: basuki@gc.itb.ac.id Search for other works by this author on: GSW Google Scholar E.T.C. Spooner E.T.C. Spooner 1F. Gordon Smith Fluid Inclusion Lab., Department of Geology, University of Toronto, 22 Russell St., Toronto, Ontario M5S 3B1. Search for other works by this author on: GSW Google Scholar Exploration and Mining Geology (2009) 18 (1-4): 25–39. https://doi.org/10.2113/gsemg.18.1-4.25 Article history received: 05 Nov 2007 accepted: 19 Apr 2009 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation N.I. Basuki, E.T.C. Spooner; Post-Early Cretaceous Mississippi Valley-type Zn-Pb Mineralization in the Bongara Area, Northern Peru: Fluid Evolution and Paleo Flow from Fluid Inclusion Evidence. Exploration and Mining Geology 2009;; 18 (1-4): 25–39. doi: https://doi.org/10.2113/gsemg.18.1-4.25 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search nav search search input Search input auto suggest search filter All ContentBy SocietyExploration and Mining Geology Search Advanced Search Abstract The Bongara area, northern Peru, contains Zn-Pb mineralization with characteristics typical of Mississippi Valley-type (MVT) systems. The northwest–southeast-trending late Triassic–Jurassic carbonate host rocks of the Pucará Group were locally replaced by early (D1) and late (D2) dolomite. Fluid inclusion microthermometric data from dolomite and sphalerite are typical of MVT ore fluids (78° to 187°C; ~15–23 wt.% CaCl2 equivalent), and do not show apparent covariation between temperature and salinity.Homogenization temperature data from D1 and D2 dolomite show a decrease from northern (mean Th = 138°C) to central (mean Th = 126°C) to southern areas (mean Th = 102°C), suggesting fluid flow from north to south. Assuming a geothermal gradient of ~30°C/km and an average surface temperature of ~20°C, the lower temperature limits might approximate the ambient host-rock temperatures, whereas the upper temperature limits may represent minimum temperatures of a deeper aquifer, probably at a maximum depth of ~6000 m. The lower temperature limits are also similar to the estimated temperatures if dolomitization and mineralization took place in the Late Cretaceous at ~2000–3000 m depth, probably during the formation of the Peruvian fold and thrust belt near the present day Peru–Ecuador border.Fluid inclusion data show that the fluids in each studied location had relatively uniform temperatures and salinities during dolomitization and mineralization. A significant salinity drop and a slight temperature decrease are observed during late calcite precipitation, suggesting mixing of brines with dilute, cooler fluids. You do not currently have access to this article.