Assessing the factors controlling high sedimentation rates from the latest Barremianeearliest Aptian in the hemipelagic setting of the restricted Organy  a Basin, NE Spain Yosmel Sanchez-Hernandez a, * , Florentin J.-M.R. Maurrasse a , Mihaela C. Melinte-Dobrinescu b , Ding He c, d , Shane K. Butler e a Florida International University (FIU), Earth and Environment Department,11200 SW 8th Street, PC 344, Miami, FL 33199, USA b National Institute of Marine Geology and Geo-ecology, 23e25 Dimitrie Onciul Street, RO-024053 Bucharest, Romania c Florida International University, Department of Chemistry & Biochemistry, 3000 NE 151st St., Miami, FL 33181, USA d Southeast Environmental Research Center, Florida International University, Miami, FL 33181, USA e Illinois State Geological Survey, Prairie Research Institute, University of Illinois at Urbana-Champaign, 615 E. Peabody Drive, Champaign, IL 61820-6918, USA article info Article history: Received 17 January 2014 Accepted in revised form 15 May 2014 Available online Keywords: Organy a Basin Latest Barremianeearliest Aptian High sedimentation rate Calcareous nannofossils High primary productivity Terrestrial fluxes abstract The Organy a Basin, southecentral Spanish Pyrenees, developed as a marginal depocenter during a rapid extensional phase of anticlockwise rotation of the Iberian plate. As a result of increased subsidence, an important change in sedimentation occurred from the late Barremian to the Aptian leading to unusually high sediment accumulation rates. Approximately 1000 m of hemipelagic marls and limestones accu- mulated during this time interval. Here we studied the basal 85 m of the hemipelagic facies of the El Pui section, Organy a Basin, that are characterized by alternating 15 cm e ~3 m thick beds of limestone and marls. Geochemical analyses indicate high total inorganic carbon (TIC) values (average 70%) suggesting enhanced CaCO 3 production and deposition. SEM analyses of the samples indicate high abundance of calcareous nannofossils, which together with the absence of shallow water taxa characteristic of the Urgonian Carbonate platform of Organy a, and the lack of sedimentary facies attributable to carbonate platform components point to nannofossils as the main source for the elevated TIC. Organic-rich levels (total organic carbon (TOC) up to 1.74%) concurrent with positive excursions up to 2‰ in d 13 C org , imply enhanced preservation of organic matter (OM) in the basin. In addition, pronounced peaks of d 13 C org higher than the global average suggest superimposed local factors related to intensified 12 C removal due to primary productivity. Biomarker analyses and the d 13 C org profile suggest an autochthonous origin of the OM from phytoplankton and possible additional contributions from microbial communities. X-ray diffraction (XRD) results attest for sustained terrestrial fluxes as the source of nutrients to the basin because of a 30% average non-carbonate bulk mineral content in the sediment. The non-carbonate fraction is dominated by quartz (average, 14%) whereas the clay mineral assemblages are characterized by high illite content (>73 relative%) with minor concentrations of kaolinite (<5%), illite /smectite mixed layers (<17%) and chlorite (<15%), consistent with a provenance from the Paleozoic metamorphic ter- ranes adjacent to the Organy a Basin. The integrated results suggest a high sediment accumulation rate (5 cm/kye7.5 cm/ky) and enhanced carbon burial during the latest Barremianeearliest Aptian in the hemipelagic setting of the El Pui section. © 2014 Elsevier Ltd. All rights reserved. 1. Introduction The causes of the occurrence of high accumulation rates within the BarremianeAptian time interval (~125 Ma) [(e.g. Angles sec- tion, southern France (Wissler et al., 2002); northern Germany (Mutterlose et al., 2009); La B edoule section southeast France, * Corresponding author. Tel.: þ1 3053482350, þ1 3057881655; fax: þ1 3053483877. E-mail addresses: ysanc016@fiu.edu, yosmel357@gmail.com (Y. Sanchez- Hernandez), maurrass@fiu.edu (F.J.-M.R. Maurrasse), melinte@geoecomar.ro (M.C. Melinte-Dobrinescu), dhe001@fiu.edu (D. He), sbutler4@illinois.edu (S.K. Butler). Contents lists available at ScienceDirect Cretaceous Research journal homepage: www.elsevier.com/locate/CretRes http://dx.doi.org/10.1016/j.cretres.2014.05.010 0195-6671/© 2014 Elsevier Ltd. All rights reserved. Cretaceous Research 51 (2014) 1e21