Abstract
Very little work has been done on the stratigraphy and sedimentology of the upper Oligocene-Lower Miocene Río Baguales Formation in the Magallanes Province of southern Chile since its original definition in 1957. A detailed stratigraphic section of the upper part of the formation exposed west of the Baguales River is presented, with an interpretation of depositional environments. This indicates a prograding shoreline in which estuary mouth, middle estuary (lagoon) and bay head delta facies are represented. Large-scale delta slope foresets indicate progradation towards the north and northwest, whereas southeast-directed cross-beds on the delta front probably suggest wave action. The general sequence reflects a gradual sea-level fall largely counteracted by tectonic subsidence, which provided the ne- cessary accommodation space for thick tidal flat and subtidal deposits to accumulate. A longer period of transgression towards the top of the succession may be related to a rise in sea-level or accelerated tectonic subsidence, whereas a major regression commencing at around 23.3 Ma probably coincides with the opening of the Drake Passage and the growth of the East Antarctic Ice Sheet.
Translated title of the contribution | Estuary deposits in the Río Baguales Formation (Chattian-Aquitanean), Magallanes Province, Chile |
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Original language | Spanish |
Pages (from-to) | 329-344 |
Number of pages | 16 |
Journal | Andean Geology |
Volume | 37 |
Issue number | 2 |
Publication status | Published - 2010 |
ASJC Scopus subject areas
- Geology
- Geochemistry and Petrology
- Stratigraphy
- Palaeontology