scholarly journals Mesoproterozoic−Early Cretaceous provenance and paleogeographic evolution of the Northern Rocky Mountains: Insights from the detrital zircon record of the Bridger Range, Montana, USA

Author(s):  
Chance B. Ronemus ◽  
Devon A. Orme ◽  
Saré Campbell ◽  
Sophie R. Black ◽  
John Cook

The Bridger Range of southwest Montana, USA, preserves one of the most temporally extensive sedimentary sections in North America, with strata ranging from Mesoproterozoic to Cretaceous in age. This study presents new detrital zircon geochronologic data from eight samples collected across this mountain range. Multidimensional scaling and non-negative matrix factorization statistical analyses are used to quantitatively unmix potential sediment sources from these and 54 samples compiled from previous studies on regional correlative strata. We interpret these sources based on reference data from preserved strata with detrital zircon signatures likely representative of ancient sediment sources. We link these sources to their sinks along sediment dispersal pathways interpreted using available paleogeographic constraints. Our results show that Mesoproterozoic strata in southwest Montana contain detritus derived from the nearby craton exposed along the southern margin of the fault-bounded Helena Embayment. Middle Cambrian strata were dominated by the recycling of local sources eroded during the development of the Great Unconformity. In Devonian−Pennsylvanian time, provenance in southwest Montana shifted to more distal sources along the northeastern to southeastern margins of Laurentia, but more western basins received detritus from outboard sources along a tectonically complicated margin. By the Late Jurassic, provenance in the developing retroarc foreland basin system was dominated by Cordilleran magmatic arcs and fold-thrust belt sources to the west. Eastward propagation of the fold-thrust belt caused recycling of Paleozoic and Jurassic detritus into the foreland basin to dominate by the Early Cretaceous.

2017 ◽  
Vol 479 ◽  
pp. 83-97 ◽  
Author(s):  
Tomas N. Capaldi ◽  
Brian K. Horton ◽  
N. Ryan McKenzie ◽  
Daniel F. Stockli ◽  
Margaret L. Odlum

2021 ◽  
Author(s):  
Anas Abbassi ◽  
Paola Cipollari ◽  
Maria Giuditta Fellin ◽  
Mohamed Najib Zaghloul ◽  
Marcel Guillong ◽  
...  

<p>During the Tertiary evolution of the Western Mediterranean subduction system, the orogenic accretion at the Maghrebian margin let the stacking of three main tectonic zones of the Rif fold-and-thrust belt: 1) the Internal Zone; 2) the “Maghrebian Flysch” Nappes; and 3) the  External Zone. In this context, a migrating foreland basin system developed between the Maghrebian orogenic belt and the adjacent African Craton. </p><p>A comprehensive reconstruction of the foreland basin system of the Rif Chain for each phase of its accretional history is still missing. In this work, by integrating field observations with quantitative biostratigraphic data from calcareous nannofossils assemblages, sandstone composition, and detrital zircon U-Pb geochronology from selected stratigraphic successions, we reconstruct the foreland basin system that in the early Miocene developed in front of the growing Rif orogen. The analyzed successions are representative of (1) the “Beliounis Facies”, made of quartz-arenites and litharenites (Numidian-like “mixed succession”), from the Predorsalian Unit; (2) the “Mérinides Facies”, made of a Numidian-like “mixed succession”, from the “Maghrebian Flysch Basin”; and (3) the classical “Numidian Facies”, exclusively made of quartzarenites, from the Intrarifian Tanger Unit.</p><p>The petrographic analyses and the detrital zircon U-Pb ages show the provenance of the quartzarenites of the “Numidian Facies” from the African Craton, whereas the sublitharenites and feldspathic litharenites, of both the “Mérinides Facies” and “Beliounis Facies”, show provenance from a cratonic area and the growing and unroofing Rif Chain, respectively. </p><p>The Alpine signature of the detrital grains sedimented into the foredeep deposits of the early Miocene orogenic system of the Rif Chain is from the feldspathic litharenites of both the Mérinides Facies and the Beni Ider Flysch. Both show Mesozoic and Cenozoic U-Pb zircon populations, with a large population of zircons centered at ca. 32 Ma. The U and Th concentration, the Th/U ratio, and the REE pattern of this population of zircons suggest a possible source area from Oligocene doleritic rock intrusions, similar to the magmatic dyke swarms (diorite) cropping out in the Malaga region ( SE Spain).</p><p>The biostratigraphic analyses pinpoint the same age for the arrival of the quartz grains in the Numidian, Mérinides, and Beliounis deposits, indicating about 1 Myr for their sedimentation (ca. 20-19 Ma, early Burdigalian). Together with field evidence, the biostratigraphic results point to an autochthonous deposition of the Numidian Sandstones on top of the Tanger Unit, allowing to delineate the early Burdigalian foreland basin system of the Rif Chain. The foreland depozone involved the Tanger Unit and received the “Numidian Facies” deposits ; the foredeep depozone hosted about 2000 m of the “Mérinides Facies” and the Beni Ider Flysch, and developed on the so-called “Flysch Basin Domain”; and, finally, the wedge-top depozone, characterized by the “Beliounis Facies”, developed on top of the Predorsalian Unit.</p><p>The Numidian Sandstones and the Numidian-like deposits analyzed in Morocco show the same age of similar deposits from Algeria, Tunisia, and Sicily, suggesting a comparable early Burdigalian tectono-sedimentary evolution along the southern branch of the Western Mediterranean subduction-related orogen.</p>


Tectonics ◽  
2014 ◽  
Vol 33 (9) ◽  
pp. 1659-1680 ◽  
Author(s):  
Mariya Levina ◽  
Brian K. Horton ◽  
Facundo Fuentes ◽  
Daniel F. Stockli

2020 ◽  
Author(s):  
Chance B. Ronemus ◽  
et al.

Analytical techniques, data reduction methods, ICP-MS zircon U-Pb datasets, comparison of age-probability curves generated using PDPs and various KDE bandwidths, sample information, and NMF details and results.


2021 ◽  
Author(s):  
Renas I. Koshnaw ◽  
Fritz Schlunegger ◽  
Daniel F. Stockli

Abstract. Recognition of new angular unconformity and synthesizing of new detrital zircon U-Pb and (U-Th)/He provenance records, including zircon (U-Th)/(He-Pb) double dating, from the NW Zagros elucidate the basin dynamics of the foreland wedge-top and intermontane units, as well as the tectonic processes in the source terranes in response to different geodynamic phases. In this contribution, we present field observations and detrital zircon provenance data from hinterland basins to reconstruct the basin dynamics and the underlying tectonic controls in the NW Zagros in the Kurdistan region of Iraq. Results reveal that the deposition of the suture zone units of the Red Beds Series (RBS; Suwais Group, Govanda Formation, Merga Group) occurred in an intermontane basin on top of folded Upper Cretaceous units with an angular unconformity. The RBS provenance data point at the Paleogene Walash-Naopurdan-Kamyaran (WNK) arc-related complex as a source area and show substantial decrease of magmatism by ~ 36 Ma, as reflected by the youngest ages peaks. New detrital zircon provenance data from the hinterland wedge-top units of the proto-Zagros foreland basin (the Tanjero, Kolosh, and Gercus Formations) exhibit exclusive derivation from the Upper Cretaceous Neotethys ophiolitic terranes, different from the provenance of the older Lower Cretaceous and Paleozoic units that are dominated by the Paleozoic and Neoproterozoic age spectra. These shifts in provenance between different tectonostratigraphic units argue for sediment route reversal from E to W in response to ophiolite obduction, arrival of the WNK complex and commencement of the continental collision during the late Eocene, followed by deposition of the RBS in the hinterland of the proto-Zagros fold-thrust belt, and paleodrainage connection with the post-collisional Neogene foreland basin.


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