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Rosenberg, R. H.; Kirby, Eric; Aslan, Andres; Karlstrom, Karl E.; Heizler, M. T.; Ouimet, William B.

doi:10.1130/ges00989.1

Cited by 15 publications

(3 citation statements)

References 111 publications

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“…In North America, prior to the Miocene, the Rocky Mountains may have been higher than today (Chase et al, 1998;Dettman & Lohmann, 2000;Fan et al, 2014;Sjostrom et al, 2006). Orographic lowering to modern elevations is reconstructed for the middle Miocene (Wolfe et al, 1997) but subsequent late Miocene uplift is also documented (Rosenberg et al, 2014). Topographic rejuvenation of the Appalachian mountain chain of eastern North America also occurred during the Miocene (Gallen et al, 2013;Pazzaglia & Gardner, 1994).…”

Section: Tectonics Paleogeography Erosion and Ocean Gatewaysmentioning

confidence: 97%

The Miocene: The Future of the Past

Steinthorsdottir

Coxall

Boer

et al. 2021

Paleoceanog and Paleoclimatol

251

179

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The Miocene epoch (23.03-5.33 Ma) was a time interval of global warmth, relative to today.Continental configurations and mountain topography transitioned toward modern conditions, and many flora and fauna evolved into the same taxa that exist today. Miocene climate was dynamic: long periods of early and late glaciation bracketed a ∼2 Myr greenhouse interval-the Miocene Climatic Optimum (MCO). Floras, faunas, ice sheets, precipitation, pCO 2 , and ocean and atmospheric circulation mostly (but not ubiquitously) covaried with these large changes in climate. With higher temperatures and moderately higher pCO 2 (∼400-600 ppm), the MCO has been suggested as a particularly appropriate analog for future climate scenarios, and for assessing the predictive accuracy of numerical climate models-the same models that are used to simulate future climate. Yet, Miocene conditions have proved difficult to reconcile with models. This implies either missing positive feedbacks in the models, a lack of knowledge of past climate forcings, or the need for re-interpretation of proxies, which might mitigate the model-data discrepancy. Our understanding of Miocene climatic, biogeochemical, and oceanic changes on broad spatial and temporal scales is still developing. New records documenting the physical, chemical, and biotic aspects of the Earth system are emerging, and together provide a more comprehensive understanding of this important time interval. Here, we review the state-of-the-art in Miocene climate, ocean circulation, biogeochemical cycling, ice sheet dynamics, and biotic adaptation research as inferred through proxy observations and modeling studies. Plain Language Summary During the Miocene time period (∼23-5 million years ago),Planet Earth looked similar to today, with some important differences: the climate was generally warmer and highly variable, while atmospheric CO 2 was not much higher. Continental-sized ice sheets were only present on Antarctica, but not in the northern hemisphere. The continents drifted to near their modernday positions, and plants and animals evolved into the many (near) modern species. Scientists study the Miocene because present-day and projected future CO 2 levels are in the same range as those reconstructed for the Miocene. Therefore, if we can understand climate changes and their biotic responses from the Miocene past, we are able to better predict current and future global changes. By comparing Miocene climate reconstructions from fossil and chemical data to climate simulations produced by computer models, scientists are able to test their understanding of the Earth system under higher CO 2 and warmer conditions than those of today. This helps in constraining future warming scenarios for the coming STEINTHORSDOTTIR ET AL.

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Section: Tectonics Paleogeography Erosion and Ocean Gatewaysmentioning

confidence: 97%

The Miocene: The Future of the Past

Steinthorsdottir

Coxall

Boer

et al. 2021

Paleoceanog and Paleoclimatol

251

179

View full text Add to dashboard Cite

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“…(5) geologically recent mantle heating (ca. 10-5 Ma; Aslan et al, 2010;Karlstrom et al, 2012;Rosenberg et al, 2014); and (6) normal forces due to asthenospheric convection (i.e., dynamic topography); <10-5 Ma; Moucha et al, 2008;Becker et al, 2014;van Wijk et al, 2018).…”

Section: Viability Of Previously Proposed Epeirogenic Uplift Mechanismsmentioning

confidence: 99%

Post-Laramide, Eocene epeirogeny in central Colorado—The result of a mantle drip?

et al. 2022

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The Southern Rocky Mountains first rose during the Laramide Orogeny (ca. 75–45 Ma), but today’s mountains and adjacent Great Plains owe their current height to later epeirogenic surface uplift. When and why epeirogeny affected the region are controversial. Sedimentation histories in two central Colorado basins, the South Park–High Park and Denver basins, shifted at 56–54 Ma from an orogenic to an epeirogenic pattern, suggesting central Colorado experienced epeirogeny at that time. To interrogate that hypothesis, we analyzed thermal histories for seven samples from central Colorado’s Arkansas Hills and High Park using thermochronometers with closure temperatures below ~180 °C, enabling us to track sample exhumation from ~5–7 km depth. Three samples are from the Cretaceous Whitehorn pluton, and four are Precambrian granitoids. All zircon and titanite (U-Th)/He dates (ZHe and THe) and one apatite fission-track (AFT) date are similar to the 67 Ma pluton emplacement age. Whitehorn dates using the lower-temperature apatite (U-Th)/He (AHe) thermochronometer are 55–41 Ma. These data require two exhumation episodes, one ca. 67–60 Ma, the second beginning at 54–46 Ma. The pluton reached the surface by 37 Ma, based on the age of volcanic tuff filling a pluton-cutting paleovalley. The Precambrian samples do not further refine this thermal history owing to the comparatively higher He closure temperature of their more radiation-damaged apatite. Laramide crustal shortening caused 67–60 Ma exhumation. Arkansas Hills shortening ended before 67 Ma, so shortening could not have caused the exhumation event that began 54–46 Ma; thermochronology supports the Eocene epeirogeny hypothesis. Epeirogeny affected >2.0 × 104 km2, from the Sawatch Range to the Denver Basin. We attribute epeirogeny to an Eocene mantle drip that likely triggered subsequent drips, causing younger exhumation events in adjacent areas.

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“…In addition, there are east-southeast-west-northwest-striking normal faults on the Rock Springs uplift (Love and Christiansen, 1985) and Piceance Basin (Cashion, 1973) that currently lack age control, but may be associated with Miocene extension. For all of these locations and syntectonic deposits, regional uplift and drainage evolution may have been driven by post-Oligocene mantle convection in the Rocky Mountain region (Karlstrom et al, 2012;Rosenberg et al, 2014), delamination of lithospheric mantle beneath in western Utah (Levander et al, 2011) and central Colorado (Hansen et al, 2013), and a combination of regional plate-related(?) extension plus mantle forcings affecting the margins of the Colorado Plateau (Ricketts et al, 2016).…”

Section: Regional Comparisonsmentioning

confidence: 99%

Cenozoic collapse of the eastern Uinta Mountains and drainage evolution of the Uinta Mountains region

et al. 2017

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Coupled detrital sanidine and zircon data, combined with sedimentological and stratigraphic observations, provide temporal constraints on the post-Laramide paleogeographic and structural evolution of the eastern Uinta Mountains region from the late Eocene to late Miocene (ca. 36-8 Ma). Maximum depositional ages (MDAs) calculated from detrital zircon U-Pb and detrital sanidine 40 Ar/ 39 Ar ages indicate that the most significant Paleogene fluvial system in the region, represented by the Bishop Conglomerate, existed from 36 to 27 Ma. The abundance of red sandstone and gray limestone clasts, paleocurrent directions, and the large number of Grenville-age detrital zircons suggest that the Uinta Mountain Group (UMG) facies of the Bishop Conglomerate are tributaries that flowed radially away from the crest of the Uinta Mountains. To the north of the Uinta Mountains, these rivers joined a mainstem river in southwestern Wyoming represented by the Bishop Conglomerate Firehole Canyon (FC) facies. This facies consists of rounded cobbleto pebble-sized quartzite clasts with minor quantities of volcanic rocks, has westward paleocurrent directions, and abundant young (younger than 40 Ma) detrital zircon and sanidine grains. Detrital sanidine age and geochemical data suggest that these young detrital grains are tephra that originated from the Basin and Range volcanic field, which was subsequently reworked into Bishop Conglomerate sediments. The more regional headwaters of the mainstem river could have been located east of the Uinta Mountains, or in the Challis and Absaroka volcanic fields and the Wind River Mountains located to the northwest of the region. The question of whether the FC facies of the Bishop Conglomerate represents part of an integrated river system that was a precursor to the Platte River remains unresolved. Extensional collapse of the eastern Uinta Mountains was marked by the cessation of Bishop Conglomerate fluvial deposition and the onset of Browns Park Formation sedimentation within the Browns Park graben beginning ca. 25 Ma. Tuffaceous sandstone and siltstone and minor quantities of carbonate accumulated in a mosaic of fluvial and lacustrine environments representing an internally drained basin. Detrital sanidine age and geochemical data for young (younger than 40 Ma) grains also support a volcanic ash-fall origin. Some of the grains originated from the Southern Rocky Mountain volcanic field, and were reworked into Browns Park Formation deposits. New MDAs of Browns Park Formation sediments that unconformably overlie Neoproterozoic UMG rocks in westernmost Browns Park provide evidence for a younger (12-8 Ma) phase of extensional collapse of the eastern Uinta Mountains that was associated with 10-20 km of northwestward-directed lengthening of the Browns Park graben. These data are compatible with models for two stages of post-Laramide epeirogenic uplift of the Uinta Mountains region, including post-12 Ma tectonism that set the stage for subsequent integration of the Green and Colorado Rivers after 8 Ma.

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Untitled

Cited by 15 publications

References 111 publications

The Miocene: The Future of the Past

The Miocene: The Future of the Past

Post-Laramide, Eocene epeirogeny in central Colorado—The result of a mantle drip?

Cenozoic collapse of the eastern Uinta Mountains and drainage evolution of the Uinta Mountains region

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