Home Members Contact Research Collaboration Publications Gallery Lectures Links How to find us	Pictures and sketches illustrating the sedimentology, stratigraphy and ichnofazies of the late Maastrichtian El Molino Formation Geographical and geological setting Picture of two trackways Depositional Environment Ichnology Profil through the El Molino Formation Tectonical setting Abstract about El Molino Formation   Above: Geographical setting of the El Molino Formation in the surroundings of Sucre, Bolivia. The studied area, Cal Orcko, Humaca and Toro Toro are all situated in the eastern part of the Cordillera Real (Bolivia). During the Late Cretaceous to early Tertiary the region formed part of the eastern margin of the central paleo-Andean Basin (Potosi-Basin) where thick terrigenous and lacustrine sediments were deposited.  Above: Geological setting of the El Molino Formation.The Sucre Formation is dominated by red sandstones alternating with siltstones and conglomerates. The mineralogic composition indicates deposition in the distal part of an extensive alluvial facies belt. Macroscopic sedimentary structures are channels, cross-stratification, muddy rip-up clasts and tube-shaped borrows.         Below: This Picture shows two parallel trackways of big sauropod Titanosaurs in the Cal Orcko quarry.  Tectonical Setting The observed tectonic structures can be connected with the general situation of the Andean orogeny related to the opening of the South Atlantic. Throughout the Mesozoic, mainly terrigenous sediments were deposited in an extensional back-arc basin (eastern part of the Central Andean basin). During this interval the study area was situated on the eastern margin where erosion was the dominant feature. Although the westward motion of the South American plate started in the Albian, Late Cretaceous to Paleocene was a time of tectonic quiescence. An increase in subsidence (foreland type subsidence) can be observed in the entire basin that leads to more accomodation space. The tectonic structures are related to the main compressive phase during the Late Paleocoene to Eocene. This leads to large-scale folding followed by dextral strike-slip faulting. The small-scale thrusting is due to ongoing, less intense deformation. All pictures are taken from a poster which was made for the 7th Swiss Sed Meeting 1999: Hippler D., Bucher, S., Meyer, Chr.-A. & Fügenschuh, B., Preliminary results on the sedimentology of the Late Cretaceous El Molino Formation (Sucre, Bolivia), Seventh Swiss Sed Meetin 1999, Abstract & Poster |Top of page|  |Back to abstract about El Molino Formation|
.	Geology -Paleontology   Institute  Department of Earth   Sciences  University of Basel Webmaster, last update