Late Jurassic paleogeographic evolution of the Andean back-arc basin

New constrains from the Lagunillas Formation, northern Chile (27°30'-28°30'S)

Verónica Oliveros, Mariana Labbé, Pablo Rossel, Reynaldo Charrier, Alfonso Encinas

Resultado de la investigación: Article

20 Citas (Scopus)

Resumen

The Late Jurassic Lagunillas Formation exposed between 27°30' and 28°30'S in the northern Chilean Andes comprises two members: a lower sedimentary member, and an upper volcanic member. This unit was deposited during a significant palaeogeographic change related to a major relative sea-level fall that took place in the Andean back-arc basin between 18° and 44°S. The sedimentary member of the Lagunillas Formation consists of a prograding succession in which distal sheetflood alluvial deposits interbedded with aeolian sandstones predominate in the lower part whereas channelized conglomerates, characteristic of more proximal alluvial fan deposition, become progressively more abundant to the top. U-Pb geochronology on detrital zircons indicate maximum depositional ages for the Lagunillas Formation at the Kimmerigdian/Tithonian boundary (150.8 ± 4.0 Ma). These results constitute the first age data for this or correlative units in Chile and indicate correlation of the Lagunillas Formation with the continental Tordillo Formation in the Neuquén basin. Provenance studies by clast count analyses and U-Pb ages in detrital zircons suggest a temporal variation in the sources of the clastic material. At the beginning of the deposition, fine-grained detritus would have been supplied mainly from the Mesozoic magmatic arc located to the west of the basin, but also from Late Paleozoic units probably located to the east. As deposition proceeded, most of the material was being supplied by Paleozoic to Neoproterozoic (" Grenvillian") units. Mesoproterozoic cratonic units, likely located further east, were exposed and eroded at the end of the deposition, prior to the onset of volcanism in the back-arc.

Idioma originalEnglish
Páginas (desde-hasta)25-40
Número de páginas16
PublicaciónJournal of South American Earth Sciences
Volumen37
DOI
EstadoPublished - 1 ago 2012

Huella dactilar

Jurassic
basin
zircon
Paleozoic
Grenvillian orogeny
Tithonian
alluvial fan
geochronology
clast
alluvial deposit
conglomerate
detritus
provenance
volcanism
temporal variation
sandstone
sea level
material

ASJC Scopus subject areas

  • Geology
  • Earth-Surface Processes

Citar esto

@article{119d54258e3a4a8791c1e8757a384737,
title = "Late Jurassic paleogeographic evolution of the Andean back-arc basin: New constrains from the Lagunillas Formation, northern Chile (27°30'-28°30'S)",
abstract = "The Late Jurassic Lagunillas Formation exposed between 27°30' and 28°30'S in the northern Chilean Andes comprises two members: a lower sedimentary member, and an upper volcanic member. This unit was deposited during a significant palaeogeographic change related to a major relative sea-level fall that took place in the Andean back-arc basin between 18° and 44°S. The sedimentary member of the Lagunillas Formation consists of a prograding succession in which distal sheetflood alluvial deposits interbedded with aeolian sandstones predominate in the lower part whereas channelized conglomerates, characteristic of more proximal alluvial fan deposition, become progressively more abundant to the top. U-Pb geochronology on detrital zircons indicate maximum depositional ages for the Lagunillas Formation at the Kimmerigdian/Tithonian boundary (150.8 ± 4.0 Ma). These results constitute the first age data for this or correlative units in Chile and indicate correlation of the Lagunillas Formation with the continental Tordillo Formation in the Neuqu{\'e}n basin. Provenance studies by clast count analyses and U-Pb ages in detrital zircons suggest a temporal variation in the sources of the clastic material. At the beginning of the deposition, fine-grained detritus would have been supplied mainly from the Mesozoic magmatic arc located to the west of the basin, but also from Late Paleozoic units probably located to the east. As deposition proceeded, most of the material was being supplied by Paleozoic to Neoproterozoic ({"} Grenvillian{"}) units. Mesoproterozoic cratonic units, likely located further east, were exposed and eroded at the end of the deposition, prior to the onset of volcanism in the back-arc.",
keywords = "Alluvial fans, Back-arc basin, Late Jurassic, Sediment provenance, U-Pb geochronology",
author = "Ver{\'o}nica Oliveros and Mariana Labb{\'e} and Pablo Rossel and Reynaldo Charrier and Alfonso Encinas",
year = "2012",
month = "8",
day = "1",
doi = "10.1016/j.jsames.2011.12.005",
language = "English",
volume = "37",
pages = "25--40",
journal = "Journal of South American Earth Sciences",
issn = "0895-9811",
publisher = "Elsevier BV",

}

TY - JOUR

T1 - Late Jurassic paleogeographic evolution of the Andean back-arc basin

T2 - New constrains from the Lagunillas Formation, northern Chile (27°30'-28°30'S)

AU - Oliveros, Verónica

AU - Labbé, Mariana

AU - Rossel, Pablo

AU - Charrier, Reynaldo

AU - Encinas, Alfonso

PY - 2012/8/1

Y1 - 2012/8/1

N2 - The Late Jurassic Lagunillas Formation exposed between 27°30' and 28°30'S in the northern Chilean Andes comprises two members: a lower sedimentary member, and an upper volcanic member. This unit was deposited during a significant palaeogeographic change related to a major relative sea-level fall that took place in the Andean back-arc basin between 18° and 44°S. The sedimentary member of the Lagunillas Formation consists of a prograding succession in which distal sheetflood alluvial deposits interbedded with aeolian sandstones predominate in the lower part whereas channelized conglomerates, characteristic of more proximal alluvial fan deposition, become progressively more abundant to the top. U-Pb geochronology on detrital zircons indicate maximum depositional ages for the Lagunillas Formation at the Kimmerigdian/Tithonian boundary (150.8 ± 4.0 Ma). These results constitute the first age data for this or correlative units in Chile and indicate correlation of the Lagunillas Formation with the continental Tordillo Formation in the Neuquén basin. Provenance studies by clast count analyses and U-Pb ages in detrital zircons suggest a temporal variation in the sources of the clastic material. At the beginning of the deposition, fine-grained detritus would have been supplied mainly from the Mesozoic magmatic arc located to the west of the basin, but also from Late Paleozoic units probably located to the east. As deposition proceeded, most of the material was being supplied by Paleozoic to Neoproterozoic (" Grenvillian") units. Mesoproterozoic cratonic units, likely located further east, were exposed and eroded at the end of the deposition, prior to the onset of volcanism in the back-arc.

AB - The Late Jurassic Lagunillas Formation exposed between 27°30' and 28°30'S in the northern Chilean Andes comprises two members: a lower sedimentary member, and an upper volcanic member. This unit was deposited during a significant palaeogeographic change related to a major relative sea-level fall that took place in the Andean back-arc basin between 18° and 44°S. The sedimentary member of the Lagunillas Formation consists of a prograding succession in which distal sheetflood alluvial deposits interbedded with aeolian sandstones predominate in the lower part whereas channelized conglomerates, characteristic of more proximal alluvial fan deposition, become progressively more abundant to the top. U-Pb geochronology on detrital zircons indicate maximum depositional ages for the Lagunillas Formation at the Kimmerigdian/Tithonian boundary (150.8 ± 4.0 Ma). These results constitute the first age data for this or correlative units in Chile and indicate correlation of the Lagunillas Formation with the continental Tordillo Formation in the Neuquén basin. Provenance studies by clast count analyses and U-Pb ages in detrital zircons suggest a temporal variation in the sources of the clastic material. At the beginning of the deposition, fine-grained detritus would have been supplied mainly from the Mesozoic magmatic arc located to the west of the basin, but also from Late Paleozoic units probably located to the east. As deposition proceeded, most of the material was being supplied by Paleozoic to Neoproterozoic (" Grenvillian") units. Mesoproterozoic cratonic units, likely located further east, were exposed and eroded at the end of the deposition, prior to the onset of volcanism in the back-arc.

KW - Alluvial fans

KW - Back-arc basin

KW - Late Jurassic

KW - Sediment provenance

KW - U-Pb geochronology

UR - http://www.scopus.com/inward/record.url?scp=84856560513&partnerID=8YFLogxK

U2 - 10.1016/j.jsames.2011.12.005

DO - 10.1016/j.jsames.2011.12.005

M3 - Article

VL - 37

SP - 25

EP - 40

JO - Journal of South American Earth Sciences

JF - Journal of South American Earth Sciences

SN - 0895-9811

ER -