Abstract
The Mesozoic rocks of southern Peru comprise a Middle Jurassic to Early Cretaceous sedimentary sequence deposited during a time interval of approximately 34 Myr. In Tacna, these rocks are detrital and constitute the Yura Group (Callovian to Tithonian) and the Hualhuani Formation (Berriasian). Basing on robust interpretation of facies and petrographic analysis, we reconstruct the depositional settings of such units and provide a refined stratigraphic framework. Accordingly, nine types of sedimentary facies and six architectural elements are defined. They preserve the record of a progradational fluvial system, in which two styless regulated the dispersion of sediments: (i) a high-to moderate-sinuosity meandering setting (Yura Group), and a later (ii) incipient braided setting (Hualhuani Formation). The Yura Group (Callovian-Tithonian) represents the onset of floodplain deposits and lateral accretion of point-bar deposits sited on a semi-flat topography. Nonetheless, the progradational sequence was affected by at least two rapid marine ingressions occurred during Middle Callovian and Tithonian times. Such marine ingressions reveal the proximity of a shallow marine setting and incipient carbonate deposition. In response to increase in topographic gradient, the Hualhuani Formation (Berriasian) deposited as extensive multistory sandy channels. The mineralogy of the Mesozoic sediments suggests sediment supplies and intense recycling from a craton interior (i.e. Amazon Craton and/or plutonic sources) located eastward of the study area.
| Original language | English |
|---|---|
| Pages (from-to) | 399-421 |
| Number of pages | 23 |
| Journal | Journal of South American Earth Sciences |
| Volume | 84 |
| DOIs | |
| State | Published - Jul 2018 |
Bibliographical note
Funding Information:The study was funded by Instituto Geológico Minero y Metalúrgico (INGEMMET) ( POI GR41A 2015-2016 , DGR) of Peru and co-funded by FONDECYT (CIENCIACTIVA of Peru) Convenio N° 216-2015 ("Registro de variaciones climaticas en los sedimentos durante el Mesozoico y Cenozoico del Sur de Perú, 18°S"). These results form part of the research project GR41A-2016 (INGEMMET) and the Sediment Research Workgroup (GeoSed, Peru). Field work, data interpretation and exhaustive discussions with Rildo Rodríguez, Harmuth Acosta, Alejandro Rosado, Cesar Chacaltana (Lima) and an anonymous reviewer strongly benefited this manuscript. We want to thanks to Astrid Criales for the support on the search of grants, as well as for her valuables advices on the manuscript organization and the graphic edition of an earlier version.
Funding Information:
The study was funded by Instituto Geológico Minero y Metalúrgico (INGEMMET) (POI GR41A 2015-2016, DGR) of Peru and co-funded by FONDECYT (CIENCIACTIVA of Peru) Convenio N° 216-2015 (“Registro de variaciones climaticas en los sedimentos durante el Mesozoico y Cenozoico del Sur de Perú, 18°S”). These results form part of the research project GR41A-2016 (INGEMMET) and the Sediment Research Workgroup (GeoSed, Peru). Field work, data interpretation and exhaustive discussions with Rildo Rodríguez, Harmuth Acosta, Alejandro Rosado, Cesar Chacaltana (Lima) and an anonymous reviewer strongly benefited this manuscript. We want to thanks to Astrid Criales for the support on the search of grants, as well as for her valuables advices on the manuscript organization and the graphic edition of an earlier version.
Publisher Copyright:
© 2018 Elsevier Ltd
Keywords
- Central Andes
- Facies Analysis
- Hualhuani Formation
- Mesozoic Arequipa Basin
- Yura Group