The sequence stratigraphic framework and a summary of the fossil fauna of the Upper Miocene portion of the Pisco Formation exposed along the western side of the Ica River (southern Peru) is presented through a new geological map encompassing an area of about 200 km2 and detailed chronostratigraphic analyses. Extensive ield mapping and sedimentological study of outcrop sections have shown that the Pisco Formation is a cyclical sediment unit composed of at least three ining-upward, unconformity-bounded depositional sequences, designated P0, P1, and P2 from oldest to youngest. In the study area, these sequences progressively onlap a composite basal unconformity from southwest to northeast. Integration of biostratigraphic and tephrochronologic age determinations constrains the ages of the three Pisco sequences within the study area. Based on the age of surrounding sediments, a conservative estimate of the age of P0 suggests deposition of these strata between 17.99 ± 0.10 Ma and 9.00 ± 0.02 Ma, whereas diatom biostratigraphy and calculated 40Ar/39Ar ages converge to indicate that strata of the P1 sequence were deposited sometime between 9.5 Ma and 8.9 Ma and that those of the P2 sequence are younger than 8.5 Ma and older than 6.71 ± 0.02 Ma. Our survey for both vertebrate and macro-invertebrate remains in the three sequences conirms the outstanding paleontological value of the Pisco Formation and contributes to depict regional faunal shifts in the fossil assemblage.

Sequence stratigraphy and paleontology of the Upper Miocene Pisco formation along the western side of the lower Ica Valley (Ica desert, Peru)

COLLARETA, ALBERTO;GARIBOLDI, KAREN;GIONCADA, ANNA;MOLLI, GIANCARLO;LANDINI, WALTER;SARTI, GIOVANNI;BIANUCCI, GIOVANNI
Ultimo
2017-01-01

Abstract

The sequence stratigraphic framework and a summary of the fossil fauna of the Upper Miocene portion of the Pisco Formation exposed along the western side of the Ica River (southern Peru) is presented through a new geological map encompassing an area of about 200 km2 and detailed chronostratigraphic analyses. Extensive ield mapping and sedimentological study of outcrop sections have shown that the Pisco Formation is a cyclical sediment unit composed of at least three ining-upward, unconformity-bounded depositional sequences, designated P0, P1, and P2 from oldest to youngest. In the study area, these sequences progressively onlap a composite basal unconformity from southwest to northeast. Integration of biostratigraphic and tephrochronologic age determinations constrains the ages of the three Pisco sequences within the study area. Based on the age of surrounding sediments, a conservative estimate of the age of P0 suggests deposition of these strata between 17.99 ± 0.10 Ma and 9.00 ± 0.02 Ma, whereas diatom biostratigraphy and calculated 40Ar/39Ar ages converge to indicate that strata of the P1 sequence were deposited sometime between 9.5 Ma and 8.9 Ma and that those of the P2 sequence are younger than 8.5 Ma and older than 6.71 ± 0.02 Ma. Our survey for both vertebrate and macro-invertebrate remains in the three sequences conirms the outstanding paleontological value of the Pisco Formation and contributes to depict regional faunal shifts in the fossil assemblage.
2017
Di Celma, Claudio; Malinverno, Elisa; Bosio, Giulia; Collareta, Alberto; Gariboldi, Karen; Gioncada, Anna; Molli, Giancarlo; Basso, Daniela; Varas Malca, Rafael M.; Pierantoni, Pietro Paolo; Villa, Igor M.; Lambert, Olivier; Landini, Walter; Sarti, Giovanni; Cantalamessa, Gino; Urbina, Mario; Bianucci, Giovanni
File in questo prodotto:
File Dimensione Formato  
8373-24817-1-SM.pdf

accesso aperto

Descrizione: articolo principale
Tipologia: Versione finale editoriale
Licenza: Creative commons
Dimensione 12.2 MB
Formato Adobe PDF
12.2 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/857053
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 72
  • ???jsp.display-item.citation.isi??? 67
social impact