Late Quaternary palaeoenvironment of northern Guatemala: evidence from deep drill cores and seismic stratigraphy of Lake Petén Itzá |
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| Authors: | ANDREAS D MUELLER FLAVIO S ANSELMETTI DANIEL ARIZTEGUI MARK BRENNER DAVID A HODELL JASON H CURTIS JAIME ESCOBAR ADRIAN GILLI DUSTIN A GRZESIK THOMAS P GUILDERSON STEFFEN KUTTEROLF MICHAEL PLÖTZE |
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| Institution: | 1. Geological Institute, Swiss Federal Institute of Technology ETH Zurich, 8092 Zurich, Switzerland (E‐mail: andreas.mueller@erdw.ethz.ch);2. Eawag (Swiss Federal Institute of Aquatic Science & Technology), Department of Surface Waters, 8600 Duebendorf, Switzerland;3. Section of Earth and Environmental Sciences, University of Geneva, 1205 Geneva, Switzerland;4. Department of Geological Sciences and Land Use and Environmental Change Institute (LUECI), University of Florida, Gainesville, FL 32611, USA;5. Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK;6. Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA;7. Leibniz Institute for Marine Sciences, IfM‐Geomar, 24148 Kiel, Germany;8. ClayLab, Institute for Geotechnical Engineering, Geological Institute, Swiss Federal Institute of Technology ETH Zurich, 8093 Zurich, SwitzerlandAssociate Editor – Chris Scholz |
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| Abstract: | Long sediment cores were collected in spring 2006 from Lake Petén Itzá, northern Guatemala, in water depths ranging from 30 to 150 m, as part of an International Continental Scientific Drilling Program project. The sediment records from deep water consist mainly of alternating clay, gypsum and carbonate units and, in at least two drill sites, extend back >200 kyr. Most of the lithostratigraphic units are traceable throughout the basin along seismic reflections that serve as seismic stratigraphic boundaries and suggest that the lithostratigraphy can be used to infer regional palaeoenvironmental changes. A revised seismic stratigraphy was established on the basis of integrated lithological and seismic reflection data from the basin. From ca 200 to ca 85 ka, sediments are dominated by carbonate‐clay silt, often interbedded with sandy turbidites, indicating a sediment regime dominated by detrital sedimentation in a relatively humid climate. At ca 85 ka, an exposure horizon consisting of gravels, coarse sand and terrestrial gastropods marks a lake lowstand or partial basin desiccation, indicating dry climate conditions. From ca 85 to ca 48 ka, transgressive carbonate‐clay sediments, overlain by deep‐water clays, suggest a lake level rise and subsequent stabilization at high stage. From ca 48 ka to present, the lithology is characterized by alternating clay and gypsum units. Gypsum deposition correlates with Heinrich Events (i.e. dry climate), whereas clay units coincide with more humid interstadials. |
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| Keywords: | Guatemala lake level changes lake sediments palaeoclimatology Peté n Itzá seismic stratigraphy |
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