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- Creator:
- Murray, Kendra E., Niemi, Nathan A., Clark, Marin K., and Siddoway, Christine
- Description:
- The Front Range of the Southern Rocky Mountains near Boulder, CO contains a rock record that spans nearly 1.7 billion years. Zircon U-Pb geochronology is an isotopically-based chronometer for measuring deep earth time. We apply this method to a series of small igneous intrusive bodies from the Front Range west of Boulder, CO. These instrusives are collectively known as the Colorado Mineral Belt (CMB) for the economic mineral deposits associated with the instrusives. Past geochronological methods have provided only rudimentary constraints on the geologic timing of emplacement of these bodies. We demonstrate the CMB magmatic activity in the Front Range occurred in two discrete pulses, one at ~67 Ma (million years ago) and one at ~47 Ma. Additional application of the same methodology to a sedimentary rock, the Neoproterozoic Tavakiav Quartzite, uses the zircon U-Pb ages as tracers to constrain the provenance and depositional age of this unique sand body.
- Keyword:
- zircon, Colorado, Front Range, geochronology, Tava, Colorado Mineral Belt, Eldorado stock, Bryan Mountain stock, Sugarloaf, Sunset stock, Bald Mountain, Caribou stock, North Fork, CMB, Front Range mineral belt, and Jamestown
- Citation to related publication:
- Murray, K. E., Niemi, N. A., & Clark, M. K. (2025). Evidence for the Neoproterozoic rifting of Rodinia in the Rocky Mountain Front Range. Tectonics, 44, e2023TC008216.
- Discipline:
- Science
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- Creator:
- Murray, Kendra E, Niemi, Nathan A, and Clark, Marin C
- Description:
- These data were produced in the scope of research into understanding the application of zircon (U-Th)/He thermochronometric data derived from rocks with complex radiation damage distributions to the extraction of long-term (>1 Gyr) thermal histories of the Earth's upper crust. The samples used in this study were collected from the Front Range in Colorado, USA. The low-temperature (apatite and zircon (U-Th)/He) thermochronometric ages presented in this data set are sensitive to near-surface temperatures (~80C and 180C, respectively) and record the progressive exhumation of the rock mass from which the samples were collected towards the Earth's surface. These thermochronometric ages, and the differences between them, provide insight into the deep-time (~1000 Ma - 100 Ma) thermal history of the Colorado Front Range.
- Keyword:
- apatite, zircon, helium, (U-Th)/He, (U-Th-Sm)/He, thermochronometry, thermochronology, low-temperature, Colorado, Boulder, geology, Colorado Mineral Belt, and Front Range
- Discipline:
- Science
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- Creator:
- Niemi, Nathan A. and Abbey, Alyssa L.
- Description:
- These data were produced in the scope of research into the timing, rate, and magnitude of extensional exhumation along the length of the Rio Grande Rift in Colorado and New Mexico. The low-temperature (apatite and zircon (U-Th)/He) thermochronometric ages presented in this data set are sensitive to near-surface temperatures (~80C and 180C, respectively) and record the progressive exhumation of the rock mass from which the samples were collected towards the Earth's surface. These thermochronometric ages, and the differences between them, provide insight into the absolute timing, exhumation rate and total magnitude of exhumation on the normal faults that bound the Rio Grande Rift. and The QTQt program mentioned (Version QTQt64R5.6.2a was used for the data presented in this deposit) is not openly available for download, but is described in the Gallagher 2012 publication referenced, and can be requested from its author. For more information on the request process and a user guide, see http://www.iearth.org.au/codes/QTQt/
- Keyword:
- thermochronology, helium dating, (U-Th)/He, Rio Grande Rift, New Mexico, Colorado, and extensional tectonics
- Citation to related publication:
- Abbey, A. L., & Niemi, N. A. (2020). Perspectives on Continental Rifting Processes From Spatiotemporal Patterns of Faulting and Magmatism in the Rio Grande Rift, USA. Tectonics, 39(1), e2019TC005635. https://doi.org/10.1029/2019TC005635
- Discipline:
- Science