Paleomagnetic evidence for a pre-early Eocene (∼ 50 Ma) bending of the Patagonian orocline (Tierra del Fuego, Argentina): Paleogeographic and tectonic implications
The southernmost segment of the Andes of southern Patagonia and Tierra del Fuego forms a ∼ 700 km long orogenic re-entrant with an interlimb angle of ∼ 90° known as Patagonian orocline. No reliable paleomagnetic evidence has been gathered so far to assess whether this great orogenic bend is a primar...
Main Author: | |
---|---|
Language: | unknown |
Published: |
2010
|
Subjects: | |
Online Access: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0012821X_v289_n1-2_p273_Maffione https://hdl.handle.net/20.500.12110/paper_0012821X_v289_n1-2_p273_Maffione |
id |
ftunibueairesbd:paper:paper_0012821X_v289_n1-2_p273_Maffione |
---|---|
record_format |
openpolar |
spelling |
ftunibueairesbd:paper:paper_0012821X_v289_n1-2_p273_Maffione 2023-05-15T13:51:24+02:00 Paleomagnetic evidence for a pre-early Eocene (∼ 50 Ma) bending of the Patagonian orocline (Tierra del Fuego, Argentina): Paleogeographic and tectonic implications Rossello, Eduardo Antonio 2010 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0012821X_v289_n1-2_p273_Maffione https://hdl.handle.net/20.500.12110/paper_0012821X_v289_n1-2_p273_Maffione unknown https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0012821X_v289_n1-2_p273_Maffione http://hdl.handle.net/20.500.12110/paper_0012821X_v289_n1-2_p273_Maffione Drake Passage Fuegian Andes Magallanes belt paleomagnetism Patagonian orocline tectonics Anisotropy of magnetic susceptibility Antarctica Argentina Early Miocene Global climates Iron sulphide Lower bounds Magnetic lineations Marine clays Orocline Paleomagnetic evidence Patagonia Relative motion Sampling site South America Strike-slip fault Strike-slip fault systems Tectonic implications Clay minerals Control theory Geomagnetism Glacial geology Iron ores Magnetic anisotropy Magnetic susceptibility Oxide minerals Rotation Structural geology bending Cretaceous-Tertiary boundary deformation mechanism displacement Eocene fold and thrust belt iron sulfide magnetite orogeny paleogeography plate motion 2010 ftunibueairesbd https://doi.org/20.500.12110/paper_0012821X_v289_n1-2_p273_Maffione 2023-02-16T02:09:54Z The southernmost segment of the Andes of southern Patagonia and Tierra del Fuego forms a ∼ 700 km long orogenic re-entrant with an interlimb angle of ∼ 90° known as Patagonian orocline. No reliable paleomagnetic evidence has been gathered so far to assess whether this great orogenic bend is a primary arc formed over an articulated paleomargin, or is due to bending of a previously less curved (or rectilinear) chain. Here we report on an extensive paleomagnetic and anisotropy of magnetic susceptibility (AMS) study carried out on 22 sites (298 oriented cores), predominantly sampled in Eocene marine clays from the external Magallanes belt of Tierra del Fuego. Five sites (out of six giving reliable paleomagnetic results) containing magnetite and subordinate iron sulphides yield a positive fold test at the 99% significance level, and document no significant rotation since ∼ 50 Ma. Thus, the Patagonian orocline is either a primary bend, or an orocline formed after Cretaceous-earliest Tertiary rotations. Our data imply that the opening of the Drake Passage between South America and Antarctica (probably causing the onset of Antarctica glaciation and global climate cooling), was definitely not related to the formation of the Patagonian orocline, but was likely the sole consequence of the 32 ± 2 Ma Scotia plate spreading. Well-defined magnetic lineations gathered at 18 sites from the Magallanes belt are sub-parallel to (mostly E-W) local fold axes, while they trend randomly at two sites from the Magallanes foreland. Our and previous AMS data consistently show that the Fuegian Andes were characterized by a N-S compression and northward displacing fold-thrust sheets during Eocene-early Miocene times (50-20 Ma), an unexpected kinematics considering coeval South America-Antarctica relative motion. Both paleomagnetic and AMS data suggest no significant influence from the E-W left-lateral Magallanes-Fagnano strike-slip fault system (MFFS), running a few kilometres south of our sampling sites. We thus speculate that strike-slip ... Other/Unknown Material Antarc* Antarctica Drake Passage Tierra del Fuego Biblioteca Digital FCEN-UBA (Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires) Argentina Drake Passage Magallanes ENVELOPE(-62.933,-62.933,-64.883,-64.883) Patagonia |
institution |
Open Polar |
collection |
Biblioteca Digital FCEN-UBA (Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires) |
op_collection_id |
ftunibueairesbd |
language |
unknown |
topic |
Drake Passage Fuegian Andes Magallanes belt paleomagnetism Patagonian orocline tectonics Anisotropy of magnetic susceptibility Antarctica Argentina Early Miocene Global climates Iron sulphide Lower bounds Magnetic lineations Marine clays Orocline Paleomagnetic evidence Patagonia Relative motion Sampling site South America Strike-slip fault Strike-slip fault systems Tectonic implications Clay minerals Control theory Geomagnetism Glacial geology Iron ores Magnetic anisotropy Magnetic susceptibility Oxide minerals Rotation Structural geology bending Cretaceous-Tertiary boundary deformation mechanism displacement Eocene fold and thrust belt iron sulfide magnetite orogeny paleogeography plate motion |
spellingShingle |
Drake Passage Fuegian Andes Magallanes belt paleomagnetism Patagonian orocline tectonics Anisotropy of magnetic susceptibility Antarctica Argentina Early Miocene Global climates Iron sulphide Lower bounds Magnetic lineations Marine clays Orocline Paleomagnetic evidence Patagonia Relative motion Sampling site South America Strike-slip fault Strike-slip fault systems Tectonic implications Clay minerals Control theory Geomagnetism Glacial geology Iron ores Magnetic anisotropy Magnetic susceptibility Oxide minerals Rotation Structural geology bending Cretaceous-Tertiary boundary deformation mechanism displacement Eocene fold and thrust belt iron sulfide magnetite orogeny paleogeography plate motion Rossello, Eduardo Antonio Paleomagnetic evidence for a pre-early Eocene (∼ 50 Ma) bending of the Patagonian orocline (Tierra del Fuego, Argentina): Paleogeographic and tectonic implications |
topic_facet |
Drake Passage Fuegian Andes Magallanes belt paleomagnetism Patagonian orocline tectonics Anisotropy of magnetic susceptibility Antarctica Argentina Early Miocene Global climates Iron sulphide Lower bounds Magnetic lineations Marine clays Orocline Paleomagnetic evidence Patagonia Relative motion Sampling site South America Strike-slip fault Strike-slip fault systems Tectonic implications Clay minerals Control theory Geomagnetism Glacial geology Iron ores Magnetic anisotropy Magnetic susceptibility Oxide minerals Rotation Structural geology bending Cretaceous-Tertiary boundary deformation mechanism displacement Eocene fold and thrust belt iron sulfide magnetite orogeny paleogeography plate motion |
description |
The southernmost segment of the Andes of southern Patagonia and Tierra del Fuego forms a ∼ 700 km long orogenic re-entrant with an interlimb angle of ∼ 90° known as Patagonian orocline. No reliable paleomagnetic evidence has been gathered so far to assess whether this great orogenic bend is a primary arc formed over an articulated paleomargin, or is due to bending of a previously less curved (or rectilinear) chain. Here we report on an extensive paleomagnetic and anisotropy of magnetic susceptibility (AMS) study carried out on 22 sites (298 oriented cores), predominantly sampled in Eocene marine clays from the external Magallanes belt of Tierra del Fuego. Five sites (out of six giving reliable paleomagnetic results) containing magnetite and subordinate iron sulphides yield a positive fold test at the 99% significance level, and document no significant rotation since ∼ 50 Ma. Thus, the Patagonian orocline is either a primary bend, or an orocline formed after Cretaceous-earliest Tertiary rotations. Our data imply that the opening of the Drake Passage between South America and Antarctica (probably causing the onset of Antarctica glaciation and global climate cooling), was definitely not related to the formation of the Patagonian orocline, but was likely the sole consequence of the 32 ± 2 Ma Scotia plate spreading. Well-defined magnetic lineations gathered at 18 sites from the Magallanes belt are sub-parallel to (mostly E-W) local fold axes, while they trend randomly at two sites from the Magallanes foreland. Our and previous AMS data consistently show that the Fuegian Andes were characterized by a N-S compression and northward displacing fold-thrust sheets during Eocene-early Miocene times (50-20 Ma), an unexpected kinematics considering coeval South America-Antarctica relative motion. Both paleomagnetic and AMS data suggest no significant influence from the E-W left-lateral Magallanes-Fagnano strike-slip fault system (MFFS), running a few kilometres south of our sampling sites. We thus speculate that strike-slip ... |
author |
Rossello, Eduardo Antonio |
author_facet |
Rossello, Eduardo Antonio |
author_sort |
Rossello, Eduardo Antonio |
title |
Paleomagnetic evidence for a pre-early Eocene (∼ 50 Ma) bending of the Patagonian orocline (Tierra del Fuego, Argentina): Paleogeographic and tectonic implications |
title_short |
Paleomagnetic evidence for a pre-early Eocene (∼ 50 Ma) bending of the Patagonian orocline (Tierra del Fuego, Argentina): Paleogeographic and tectonic implications |
title_full |
Paleomagnetic evidence for a pre-early Eocene (∼ 50 Ma) bending of the Patagonian orocline (Tierra del Fuego, Argentina): Paleogeographic and tectonic implications |
title_fullStr |
Paleomagnetic evidence for a pre-early Eocene (∼ 50 Ma) bending of the Patagonian orocline (Tierra del Fuego, Argentina): Paleogeographic and tectonic implications |
title_full_unstemmed |
Paleomagnetic evidence for a pre-early Eocene (∼ 50 Ma) bending of the Patagonian orocline (Tierra del Fuego, Argentina): Paleogeographic and tectonic implications |
title_sort |
paleomagnetic evidence for a pre-early eocene (∼ 50 ma) bending of the patagonian orocline (tierra del fuego, argentina): paleogeographic and tectonic implications |
publishDate |
2010 |
url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0012821X_v289_n1-2_p273_Maffione https://hdl.handle.net/20.500.12110/paper_0012821X_v289_n1-2_p273_Maffione |
long_lat |
ENVELOPE(-62.933,-62.933,-64.883,-64.883) |
geographic |
Argentina Drake Passage Magallanes Patagonia |
geographic_facet |
Argentina Drake Passage Magallanes Patagonia |
genre |
Antarc* Antarctica Drake Passage Tierra del Fuego |
genre_facet |
Antarc* Antarctica Drake Passage Tierra del Fuego |
op_relation |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0012821X_v289_n1-2_p273_Maffione http://hdl.handle.net/20.500.12110/paper_0012821X_v289_n1-2_p273_Maffione |
op_doi |
https://doi.org/20.500.12110/paper_0012821X_v289_n1-2_p273_Maffione |
_version_ |
1766255257488195584 |