4 Sedimentary Systems and Provenance in the Western Cordillera

This session invites contributions on sedimentary processes, depositional environments, stratigraphic frameworks, and provenance evolution across western North America. Topics may include basin analysis, source-to-sink studies, and applications of stratigraphy to energy and environmental questions.

Wednesday, 22 April 2026
8:00 AM - 12:00 PM
LMH, Fiesta Terrace Salon

Tectonic Reassessment of the Tahue Terrane (Guerrero Composite Terrane) from Sm–Nd Isotopes and U–Pb Detrital Zircon Ages

Paper number: 4-3
Program: Technical Sessions
Time: 8:45 AM – 9:05 AM

Authors

Abstract

The Guerrero Terrane was initially suggested based on the widespread Cretaceous volcano- sedimentary successions of arc affinity that dominate Western Mexico's stratigraphy. Isolated outcrops of older rocks within the terrane indicated a more complex tectonic history before Cretaceous times, implying Paleozoic and Early Mesozoic accretionary and rifting events. In other words, rocks once thought to be allochthonous relative to North America are overlapping units covering a mosaic of older tectonic assemblages. Consequently, based on the nature of these older rocks, the Guerrero was redefined as a composite terrane (GCT) and divided into four terranes. The Tahue terrane, situated in Sinaloa, contains the oldest rocks within the GCT. From north to south, these are: the Rio Fuerte (Ordovician to Mississippian age), the San José de Gracia (Ordovician), and the Venadillo (Jurassic?) formations. The contact with the Triassic-Jurassic accretionary complex from the Zihuatanejo Terrane to the south remains unknown. Vega- Granillo et al. (2020) reported detrital zircon ages from the Rio Fuerte Formation, with clusters at 334 Ma, 475-673 Ma, 1048-1120 Ma, and 1.5-2.2 Ga. Our detrital zircon analysis from sandstone samples of the San José de Gracia formation showed a Peace River Arch signature, with two main clusters at 1.8-2.1 Ga and 2.6-2.9 Ga. This provenance is similar to coeval stratigraphic units found in Sonora and the central Baja California Peninsula. The Venadillo Formation shows Sm/Nd model ages of 1.2 to 1.4 Ga and negative ENd (- 7. 8 to -9. 6), similar to those from the sedimentary matrix of the Arteaga Complex. U/Pb detrital zircon ages' main cluster peaks at 256 Ma and is similar to the primary cluster of the Potosí Fan of central Mexico and the Arteaga complex sedimentary matrix. The younger cluster at 175 Ma is interpreted as the maximum depositional age. The sample shows a broad range of older ages, with clusters at 450-664 Ma, 1.0-1.3 Ga, and 1.9-2.0 Ga. Provenance of the Venadillo Formation suggests a mixture of Potosí Fan-Oaxaquia-derived sediments and sediments from Paleozoic sources, such as the Rio Fuerte Formation, and is similar to that of the Los Cuarzos Formation on the western margin of Oaxaquia. Paleogeographic implications will be discussed.

Geological Society of America Abstracts with Programs. Vol. 58, No. 3

doi: 10.1130/abs/2026CD-411034

© Copyright 2026 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.