Summary of the Ancestral Rocky Mountains epeirogeny in Wyoming and adjacent areas

Maughan, Edwin K.

doi:10.3133/ofr90447

Cited by 5 publications

(14 citation statements)

References 3 publications

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“…Models resolve reheating to maximum Phanerozoic temperatures by Devonian time, followed by an episode of later Paleozoic cooling. This cooling is contemporaneous with the Antler and ARM orogenic events, suggesting an episode of tectonic exhumation broadly consistent with sedimentologic and stratigraphic observations (Dorobek et al, 1991;Maughan, 1990). Our data provide the first thermochronologic evidence that the Beartooth Mountains experienced thermal effects associated with Paleozoic tectonism and suggest associated deformation penetrated further into the foreland than formerly appreciated.…”

Section: Discussionsupporting

confidence: 86%

“…Additional data from regions near the margin of Laurentia are essential to increase the spatiotemporal resolution of the thermal history of the craton, potentially helping constrain the thermal effects of rifting and driver(s) of Precambrian exhumation of the Laurentian continent. What is the Paleozoic burial and uplift history of the Beartooth Mountains? Sedimentologic and stratigraphic studies in the 1990s suggested the Beartooth Mountains comprised a paleohigh during late Paleozoic time, potentially reflecting uplift associated with the Antler and/or Ancestral Rocky Mountains (ARM) orogenic events (Dorobek et al., 1991; Maughan, 1990, 1993). Despite this sedimentologic support, recent thermochronologic investigation has failed to resolve Paleozoic cooling associated with this hypothesized episode of tectonism (e.g., Carrapa et al., 2019; Peyton et al., 2012).…”

Section: Introductionmentioning

confidence: 99%

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Orogens of Big Sky Country: Reconstructing the Deep‐Time Tectonothermal History of the Beartooth Mountains, Montana and Wyoming, USA

et al. 2023

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Thank you, Miranda Grover, for being the most supportive person in the world. I would have certainly lost weight and likely sanity without your nurturing love, understanding, and latenight leftover deliveries. I am grateful to my friend Caden Howlett-every discussion with you leaves me with a renewed enthusiasm for the mysteries of the natural world. Thank you to Stuart Parker, Mariah Romero, Sophie Black, and other student researchers for serving as sources of geologic inspiration. I am indebted to my undergraduate and graduate professors for sharing their knowledge and excitement with me. I am grateful to Dr. Colleen Elliot, Katie McDonald, and others at the MBMG for sharing their knowledge of Montana geology. I am also thankful to Chris Kussmaul, Dom D'Amato, Chris Baird, and others who assisted me with field work. I express immense love and appreciation for my mother and father-Amby and Kyle Ronemus-to whom I owe the entirety of my curiosity. Thank you for your support, encouragement, and understanding unceasing since the day I was born. Finally, this project would not have been possible without financial support from Montana State University, the MSU Department of Earth Sciences and the Tobacco Root Geological Society.

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Section: Discussionsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Orogens of Big Sky Country: Reconstructing the Deep‐Time Tectonothermal History of the Beartooth Mountains, Montana and Wyoming, USA

et al. 2023

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“…Pennsylvanian‐Permian samples (Figure b) record the introduction of eastern Laurentian DZ to western North America via transcontinental paleodispersal systems, with late Mesoproterozoic to Paleozoic DZ age groups transported across the overfilled Alleghany foreland from the uplifted Grenville and Alleghany orogenic belts (Figure c; May et al, ; Link et al, ; Chapman & Laskowski, ). Archean and Proterozoic DZ were reworked from Paleozoic strata that were exhumed during uplift of the Ancestral Rocky Mountains (May et al, ), from local uplifted areas near/within southwestern Montana (Cressman & Swanson, ; Schwartz & DeCelles, ), and from undetermined western sources (Link et al, ), with possible first‐cycle input from Ancestral Rocky Mountains basement exposures (Maughan, ).…”

Section: Discussionmentioning

confidence: 99%

Orogenic Recycling of Detrital Zircons Characterizes Age Distributions of North American Cordilleran Strata

Schwartz

Weislogel

2019

Tectonics

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Detrital zircon (DZ) analysis has become the standard tool for source-to-sink sediment routing studies at many spatial and temporal scales. In North American source-to-sink studies, DZ distributions are commonly classified according to the presence/absence and proportions of DZ age groups associated with North American crustal provinces as well as peri-Gondwanan and Cordilleran terranes. Although such a classification scheme is descriptive, these age groups typically do not uniquely identify most recent DZ source areas. Using a compilation of >19,000 individual DZ ages for Mesoproterozoic-Paleogene strata of the northern Rocky Mountains, including 2,053 new analyses from the Paleogene Renova Formation and its equivalents in southwestern Montana, we demonstrate periodic derivation of first-cycle DZ from crystalline sources and widespread recycling of poly-cycle DZ from sedimentary sources over multimillion-year timescales. Results show that (1) DZ age distributions become increasingly complex between Mesoproterozoic and Paleogene time with the introduction of new DZ sources to the study area, but (2) once an age group appears in the northern Rocky Mountains stratigraphy, grains of that age persist up-section. These trends show that most DZ age groups are spatiotemporally ubiquitous and nonunique. We largely attribute this to periodic, tectonically induced recycling of DZ into progressively younger sedimentary systems, rather than prolonged derivation of DZ from crystalline basement sources, a trend that reflects the growth of increasingly complex topography associated with the North American Cordillera.

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“…In Montana, far-field stresses from this collision are interpreted to have caused subsidence of the central Montana trough and uplift of a lowland in the Beartooth shelf region (Fig. 1; Maughan, 1990).…”

Section: Geologic Settingmentioning

confidence: 99%

“…7C; Mallory, 1972). These blocks were exhumed by the Ancestral Rockies orogeny (Kluth and Coney, 1981;Maughan, 1990), which resulted in basement uplift of Proterozoic crust in the four-corners region through Wyoming due to collision with South America/ Africa along the southern margin of Laurentia.…”

Section: Pennsylvanianmentioning

confidence: 99%

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

et al. 2020

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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.

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Summary of the Ancestral Rocky Mountains epeirogeny in Wyoming and adjacent areas

Cited by 5 publications

References 3 publications

Orogens of Big Sky Country: Reconstructing the Deep‐Time Tectonothermal History of the Beartooth Mountains, Montana and Wyoming, USA

Orogens of Big Sky Country: Reconstructing the Deep‐Time Tectonothermal History of the Beartooth Mountains, Montana and Wyoming, USA

Orogenic Recycling of Detrital Zircons Characterizes Age Distributions of North American Cordilleran Strata

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

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