About This Item
Share This Item
Abstract
Chapter from: M
62: Petroleum Basins of South America
Edited by
A. J. Tankard, R. Suarez Soruco, and H. J. WelsinkAuthors:
C. J. Schmidt, R. A. Astini, C. H. Costa, C. E. Gardini,
and P. E. Kraemer Basin and Aerial Analysis/Evaluation
Published 1995 as
part of Memoir 62
Copyright © 1995 The American Association of Petroleum
Geologists. All Rights Reserved. |
 |
|---|
|
|---|
|
Cretaceous
Rifting, Alluvial Fan Sedimentation,
and Neogene Inversion,
Southern Sierras Pampeanas,
Argentina
|
|---|
|
|---|
|
C. J. Schmidt
Department of Geology
Western Michigan University
Kalamazoo, Michigan,
U.S.A.
R. A. Astini
Facultad de Ciencias
Exactas
Físicas y Naturales
Universidad Nacional
de Córdoba
Córdoba, Argentina
|
|
C. H. Costa
C. E. Gardini
Departamento de Geología
Universidad Nacional
de San Luis
San Luis, Argentina
P. E. Kraemer
Facultad de Ciencias
Exactas Físicas y Naturales
Universidad Nacional
de Córdoba
Córdoba, Argentina
|
|
|---|
|
|---|
|
Abstract
Two north-trending, west-verging,
 fault -bounded Neogene basement uplift systems (Sierras Chicas of Córdoba
and Serranías Occidentales of San Luis) of the Sierras Pampeanas
of central Argentina are inverted Early Cretaceous rifts. Their geometry
and position 2000 km from the Atlantic continental margin and the geometry
of Neogene inversion is dependent on the earlier fabric of the basement
rocks. The trends of reactivated faults in the rifts are consistent with
an Early Cretaceous extension direction orthogonal to the Atlantic spreading
center. The principal north-northwest rift trends were produced by dextral-oblique
rifting along previous basement sutures, and isolated depocenters may have
formed as transtensional pull-apart basins. The Sierras Chicas are the
easternmost of the Pampean uplifts. They were uplifted along the eastward-dipping
Punilla thrust fault zone. Three Cretaceous depocenters containing two
depositional megasequences and volcanics are preserved as remnants of a
larger basin. The sediments were deposited in restricted half-grabens dominated
by alluvial fans and playa lakes. Paleocurrent analyses indicate that the
Punilla fault was a normal fault during deposition.
Neogene inversion of normal
fault trends thrusted proximal fanglomerates over their former source terrain.
Cretaceous rocks on the hanging wall of the Punilla fault zone were folded
into a west-verging monocline in the Sierra de Pajarillo area. The steep
limb of the monocline is underlain by a fault-bounded wedge of cataclastically
deformed basement rocks.
The Serranías Occidentales
of San Luis are similar to the Sierras Chicas of Córdoba. Depositional
environments are similar, and fault -bounded depocenters can be identified
within the larger Cretaceous San Luis basin. The Cretaceous normal faults
follow basement fabric. Neogene inversion of the Serranías Occidentales
produced short-cut faults and back-thrusts, a vertical thrust-bounded Cretaceous
section (at Sierra Quijadas), and a dramatic change of trend (north-northwest
to northeast) in the basement thrust faults (Sierra del Gigante). |
|---|
Pay-Per-View Purchase Options
The article is available through a document delivery service. Explain these Purchase Options.
| Watermarked PDF Document: $14 |
Watermarked Document – A Watermarked Document is branded with the name of the original licensed customer to discourage unauthorized users from sharing the document outside the user's organization. The PDF is no longer restricted to one machine, but can be circulated to others in the same company or department. A Watermarked Document also can be printed for hard copy distribution internally but is not authorized for outside distribution nor posting on the internet. Users will not be able to cut-and-paste text or images from one document to another.
|
| Open PDF Document: $24 |
Open Document – An Open Document is a fully functional PDF that can be circulated (a digital copy or hard-copy printed documents) outside the purchasing organization. Purchase of an Open Document does NOT constitute license for republication in any form, nor does it allow web posting without prior written permission from AAPG/Datapages ([email protected]).
|
GIS Map Publishing Program
