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Title: On the origin of Laurentia

Abstract

Laurentia, the Precambrian core of the North American continent, is surrounded by late Precambrian rift systems and therefore constitutes a suspect terrane''. A geometric and geological fit can be achieved between the Atlantic margin of Laurentia and the Pacific margin of the Gondwana craton. The enigmatic Arequipa massif along the southern Peruvian coast, that yields ca. 2.0 Ga radiometric ages, is juxtaposed with the Makkovik-Ketilidian province of the same age range in Labrador and southern Greenland. The Greenville belt continues beneath the ensialic Andes of the present day to join up with the 1.3--1.0 Ga San Ignacio and Sonsas-Aguapei orogens of the Transamazonian craton. Together with the recent identification of possible continuations of the Greenville orogen in East Antarctica and of the Taconic Appalachians in southern South America, the fit supports suggestions that Laurentia originated between East Antarctica-Australia and embryonic South America prior to the opening of the Pacific Ocean basin and amalgamation of the Gondwana Cordilleran and Appalachian margins, this implies that there may have been two supercontinents during the Neoproterozoic, before and after opening of the Pacific Ocean. As Laurentia and Gondwana appear to have collided on at least two occasions during the Paleozoic, this scenario therefore callsmore » to question the existence of so-called supercontinental cycles. The Arica bight of the present day may reflect a primary reentrant in the South American continental margin that controlled subduction processes along the Andean margin and eventually led to uplift of the Altiplano.« less

Authors:
 [1]
  1. Univ. of Texas, Austin, TX (United States). Inst. for Geophysics
Publication Date:
OSTI Identifier:
5882854
Report Number(s):
CONF-921058-
Journal ID: ISSN 0016-7592; CODEN: GAAPBC
Resource Type:
Conference
Journal Name:
Geological Society of America, Abstracts with Programs; (United States)
Additional Journal Information:
Journal Volume: 24:7; Conference: 1992 annual meeting of the Geological Society of America (GSA), Cincinnati, OH (United States), 26-29 Oct 1992; Journal ID: ISSN 0016-7592
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; NORTH AMERICA; PLATE TECTONICS; ANTARCTICA; AUSTRALIA; CORRELATIONS; GEOLOGIC FORMATIONS; GEOLOGIC MODELS; GONDWANA; ORIGIN; PRECAMBRIAN ERA; RIFT ZONES; ANTARCTIC REGIONS; AUSTRALASIA; CRYOSPHERE; DEVELOPED COUNTRIES; GEOLOGIC AGES; GEOLOGIC STRUCTURES; POLAR REGIONS; TECTONICS; 580000* - Geosciences

Citation Formats

Dalziel, I W.D. On the origin of Laurentia. United States: N. p., 1992. Web.
Dalziel, I W.D. On the origin of Laurentia. United States.
Dalziel, I W.D. Wed . "On the origin of Laurentia". United States.
@article{osti_5882854,
title = {On the origin of Laurentia},
author = {Dalziel, I W.D.},
abstractNote = {Laurentia, the Precambrian core of the North American continent, is surrounded by late Precambrian rift systems and therefore constitutes a suspect terrane''. A geometric and geological fit can be achieved between the Atlantic margin of Laurentia and the Pacific margin of the Gondwana craton. The enigmatic Arequipa massif along the southern Peruvian coast, that yields ca. 2.0 Ga radiometric ages, is juxtaposed with the Makkovik-Ketilidian province of the same age range in Labrador and southern Greenland. The Greenville belt continues beneath the ensialic Andes of the present day to join up with the 1.3--1.0 Ga San Ignacio and Sonsas-Aguapei orogens of the Transamazonian craton. Together with the recent identification of possible continuations of the Greenville orogen in East Antarctica and of the Taconic Appalachians in southern South America, the fit supports suggestions that Laurentia originated between East Antarctica-Australia and embryonic South America prior to the opening of the Pacific Ocean basin and amalgamation of the Gondwana Cordilleran and Appalachian margins, this implies that there may have been two supercontinents during the Neoproterozoic, before and after opening of the Pacific Ocean. As Laurentia and Gondwana appear to have collided on at least two occasions during the Paleozoic, this scenario therefore calls to question the existence of so-called supercontinental cycles. The Arica bight of the present day may reflect a primary reentrant in the South American continental margin that controlled subduction processes along the Andean margin and eventually led to uplift of the Altiplano.},
doi = {},
url = {https://www.osti.gov/biblio/5882854}, journal = {Geological Society of America, Abstracts with Programs; (United States)},
issn = {0016-7592},
number = ,
volume = 24:7,
place = {United States},
year = {1992},
month = {1}
}

Conference:
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