Pb isotope evidence for Colombia-southern México connections in the Proterozoic

Joaquin Ruiz, Richard M. Tosdal, Pedro A. Restrepo, Gustavo Murillo-Muñetón

Research output: Contribution to journalArticle

74 Citations (Scopus)

Abstract

Identical present-day lead isotope compositions of whole rocks from the Mesoproterozoic Guichicovi and Oaxaca Complexes in southern México and Grenville rocks from the Mesoproterozoic Santa Marta and Garzón Massifs in the Colombian Andes indicate these now widely separated Grenville-age rocks shared a U/Pb history that was distinct from Grenville-age rocks from northern and east-central México, and Texas and parts of the Appalachians in the United States. The southern México-Colombian rocks are characterized by a large range of 206Pb/204Pb values (17.5-24.6) and a corresponding range of 207Pb/204Pb values (15.53-16.31) that scatter along two 1,250 ± 50 Ma reference isochrons that lie above and below the average crustal growth curve. Variable Th/U values, indicated by a wide range of 208Pb/204Pb values (36.8-45.1), characterize the complexes, with rocks of the Guichicovi Complex and the Garzón Massif sharing low time-integrated Th/U values whereas the Santa Marta Massif has a tendency toward elevated Th/U values. These Pb isotopic similarities provide additional constraints to reconstructions of the pre-Pangea collisions between Gondwana and Laurentia. The Pb isotopic data, coupled with paleontologic data from unconformably overlying Early Paleozoic rocks, suggest that these Grenville-age basement blocks shared a common history in the late Proterozoic, and that they were part of Gondwana during the early Paleozoic. The southern México rocks, the Oaxaca and Guichicovi Complexes, are considered to have been transferred from that part of northwestern Gondwana now occupied by Colombia to the southern tip of Laurentia during Paleozoic orogenic events related to the opening and closing of the proto-Atlantic Ocean. This model requires a major suture separating México Grenville-age rock, which are considered to be offset pieces of the Grenville Province of Laurentia, from Gondwanan crust in southern México; the suture must lie north of the Guichicovi-Oaxaca Complexes. The Pb isotopic data also require that the Mesoproterozoic megaterrane Oaxaquia consists of several discrete blocks assembled in the late Proterozoic(?) or Paleozoic.

Original languageEnglish (US)
Pages (from-to)183-197
Number of pages15
JournalSpecial Paper of the Geological Society of America
Volume336
DOIs
StatePublished - 1999

Fingerprint

Proterozoic
isotope
rock
Laurentia
Paleozoic
Gondwana
Pangaea
lead isotope
growth curve
history
collision
crust
ocean

ASJC Scopus subject areas

  • Geology

Cite this

Pb isotope evidence for Colombia-southern México connections in the Proterozoic. / Ruiz, Joaquin; Tosdal, Richard M.; Restrepo, Pedro A.; Murillo-Muñetón, Gustavo.

In: Special Paper of the Geological Society of America, Vol. 336, 1999, p. 183-197.

Research output: Contribution to journalArticle

Ruiz, Joaquin ; Tosdal, Richard M. ; Restrepo, Pedro A. ; Murillo-Muñetón, Gustavo. / Pb isotope evidence for Colombia-southern México connections in the Proterozoic. In: Special Paper of the Geological Society of America. 1999 ; Vol. 336. pp. 183-197.
@article{76738b4e6bcf42a0a0b0a1495b7dc697,
title = "Pb isotope evidence for Colombia-southern M{\'e}xico connections in the Proterozoic",
abstract = "Identical present-day lead isotope compositions of whole rocks from the Mesoproterozoic Guichicovi and Oaxaca Complexes in southern M{\'e}xico and Grenville rocks from the Mesoproterozoic Santa Marta and Garz{\'o}n Massifs in the Colombian Andes indicate these now widely separated Grenville-age rocks shared a U/Pb history that was distinct from Grenville-age rocks from northern and east-central M{\'e}xico, and Texas and parts of the Appalachians in the United States. The southern M{\'e}xico-Colombian rocks are characterized by a large range of 206Pb/204Pb values (17.5-24.6) and a corresponding range of 207Pb/204Pb values (15.53-16.31) that scatter along two 1,250 ± 50 Ma reference isochrons that lie above and below the average crustal growth curve. Variable Th/U values, indicated by a wide range of 208Pb/204Pb values (36.8-45.1), characterize the complexes, with rocks of the Guichicovi Complex and the Garz{\'o}n Massif sharing low time-integrated Th/U values whereas the Santa Marta Massif has a tendency toward elevated Th/U values. These Pb isotopic similarities provide additional constraints to reconstructions of the pre-Pangea collisions between Gondwana and Laurentia. The Pb isotopic data, coupled with paleontologic data from unconformably overlying Early Paleozoic rocks, suggest that these Grenville-age basement blocks shared a common history in the late Proterozoic, and that they were part of Gondwana during the early Paleozoic. The southern M{\'e}xico rocks, the Oaxaca and Guichicovi Complexes, are considered to have been transferred from that part of northwestern Gondwana now occupied by Colombia to the southern tip of Laurentia during Paleozoic orogenic events related to the opening and closing of the proto-Atlantic Ocean. This model requires a major suture separating M{\'e}xico Grenville-age rock, which are considered to be offset pieces of the Grenville Province of Laurentia, from Gondwanan crust in southern M{\'e}xico; the suture must lie north of the Guichicovi-Oaxaca Complexes. The Pb isotopic data also require that the Mesoproterozoic megaterrane Oaxaquia consists of several discrete blocks assembled in the late Proterozoic(?) or Paleozoic.",
author = "Joaquin Ruiz and Tosdal, {Richard M.} and Restrepo, {Pedro A.} and Gustavo Murillo-Mu{\~n}et{\'o}n",
year = "1999",
doi = "10.1130/0-8137-2336-1.183",
language = "English (US)",
volume = "336",
pages = "183--197",
journal = "Special Paper of the Geological Society of America",
issn = "0072-1077",
publisher = "Geological Society of America",

}

TY - JOUR

T1 - Pb isotope evidence for Colombia-southern México connections in the Proterozoic

AU - Ruiz, Joaquin

AU - Tosdal, Richard M.

AU - Restrepo, Pedro A.

AU - Murillo-Muñetón, Gustavo

PY - 1999

Y1 - 1999

N2 - Identical present-day lead isotope compositions of whole rocks from the Mesoproterozoic Guichicovi and Oaxaca Complexes in southern México and Grenville rocks from the Mesoproterozoic Santa Marta and Garzón Massifs in the Colombian Andes indicate these now widely separated Grenville-age rocks shared a U/Pb history that was distinct from Grenville-age rocks from northern and east-central México, and Texas and parts of the Appalachians in the United States. The southern México-Colombian rocks are characterized by a large range of 206Pb/204Pb values (17.5-24.6) and a corresponding range of 207Pb/204Pb values (15.53-16.31) that scatter along two 1,250 ± 50 Ma reference isochrons that lie above and below the average crustal growth curve. Variable Th/U values, indicated by a wide range of 208Pb/204Pb values (36.8-45.1), characterize the complexes, with rocks of the Guichicovi Complex and the Garzón Massif sharing low time-integrated Th/U values whereas the Santa Marta Massif has a tendency toward elevated Th/U values. These Pb isotopic similarities provide additional constraints to reconstructions of the pre-Pangea collisions between Gondwana and Laurentia. The Pb isotopic data, coupled with paleontologic data from unconformably overlying Early Paleozoic rocks, suggest that these Grenville-age basement blocks shared a common history in the late Proterozoic, and that they were part of Gondwana during the early Paleozoic. The southern México rocks, the Oaxaca and Guichicovi Complexes, are considered to have been transferred from that part of northwestern Gondwana now occupied by Colombia to the southern tip of Laurentia during Paleozoic orogenic events related to the opening and closing of the proto-Atlantic Ocean. This model requires a major suture separating México Grenville-age rock, which are considered to be offset pieces of the Grenville Province of Laurentia, from Gondwanan crust in southern México; the suture must lie north of the Guichicovi-Oaxaca Complexes. The Pb isotopic data also require that the Mesoproterozoic megaterrane Oaxaquia consists of several discrete blocks assembled in the late Proterozoic(?) or Paleozoic.

AB - Identical present-day lead isotope compositions of whole rocks from the Mesoproterozoic Guichicovi and Oaxaca Complexes in southern México and Grenville rocks from the Mesoproterozoic Santa Marta and Garzón Massifs in the Colombian Andes indicate these now widely separated Grenville-age rocks shared a U/Pb history that was distinct from Grenville-age rocks from northern and east-central México, and Texas and parts of the Appalachians in the United States. The southern México-Colombian rocks are characterized by a large range of 206Pb/204Pb values (17.5-24.6) and a corresponding range of 207Pb/204Pb values (15.53-16.31) that scatter along two 1,250 ± 50 Ma reference isochrons that lie above and below the average crustal growth curve. Variable Th/U values, indicated by a wide range of 208Pb/204Pb values (36.8-45.1), characterize the complexes, with rocks of the Guichicovi Complex and the Garzón Massif sharing low time-integrated Th/U values whereas the Santa Marta Massif has a tendency toward elevated Th/U values. These Pb isotopic similarities provide additional constraints to reconstructions of the pre-Pangea collisions between Gondwana and Laurentia. The Pb isotopic data, coupled with paleontologic data from unconformably overlying Early Paleozoic rocks, suggest that these Grenville-age basement blocks shared a common history in the late Proterozoic, and that they were part of Gondwana during the early Paleozoic. The southern México rocks, the Oaxaca and Guichicovi Complexes, are considered to have been transferred from that part of northwestern Gondwana now occupied by Colombia to the southern tip of Laurentia during Paleozoic orogenic events related to the opening and closing of the proto-Atlantic Ocean. This model requires a major suture separating México Grenville-age rock, which are considered to be offset pieces of the Grenville Province of Laurentia, from Gondwanan crust in southern México; the suture must lie north of the Guichicovi-Oaxaca Complexes. The Pb isotopic data also require that the Mesoproterozoic megaterrane Oaxaquia consists of several discrete blocks assembled in the late Proterozoic(?) or Paleozoic.

UR - http://www.scopus.com/inward/record.url?scp=84870930538&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84870930538&partnerID=8YFLogxK

U2 - 10.1130/0-8137-2336-1.183

DO - 10.1130/0-8137-2336-1.183

M3 - Article

AN - SCOPUS:84870930538

VL - 336

SP - 183

EP - 197

JO - Special Paper of the Geological Society of America

JF - Special Paper of the Geological Society of America

SN - 0072-1077

ER -