Author ORCID Identifier
https://orcid.org/0000-0002-1119-3990
Date Available
8-12-2025
Year of Publication
2025
Document Type
Doctoral Dissertation
Degree Name
Doctor of Philosophy (PhD)
College
Arts and Sciences
Department/School/Program
Earth and Environmental Sciences (Geology)
Faculty
David P. Moecher
Abstract
The Grenvillian orogeny and Midcontinent Rift shaped the Mesoproterozoic basement of eastern Laurentia. Their convergence beneath Kentucky and Ohio formed a foreland basin, preserved as the Middle Run Formation. Detrital zircon U-Pb geochronology constrains deposition to ~1.0 Ga, reflects Grenville unroofing phases, includes Midcontinent Rift input, and minor Ottawan components. This formation constitutes the most proximal preserved segment of the Grenvillian clastic wedge in Laurentia.
Neoproterozoic-Cambrian rifting followed by Cambrian transgression formed the Great Unconformity in eastern Laurentia. Detrital zircon and basement U-Pb ages from Kentucky and the Appalachians constrain sediment provenance and recycling. Kentucky basement shows Eastern Granite-Rhyolite crust reworked by Grenvillian events. Cambrian sandstones reflect Grenville-related ages, rift magmatism, and Meso-Paleoproterozoic crust. These successions sourced Grenvillian zircon that define the “Appalachian signature” in later Phanerozoic sediments.
The Grenville orogen lacks an exposed foreland basin across North America. U-Pb zircon data from Lanoria and Hazel Formations, and coeval Thunderbird rhyolite and Red Bluff Granite, west Texas, allow comparison with the Middle Run Formation. Lanoria ( > 1117 Ma) and Hazel (1035 Ma) show distinct provenance patterns. Similarities between Hazel and Middle Run Formations support a widespread foreland basin in the U.S. midcontinent during the Grenvillian orogeny.
Digital Object Identifier (DOI)
https://doi.org/10.13023/etd.2025.304
Funding Information
This study was supported by the National Science Foundation EAR-Tectonics Research Grant (no. 1624663) in 2016.
Recommended Citation
Clay, John M. III, "GEOCHRONOLOGIC CONSTRAINTS ON THE MESO-NEOPROTEROZOIC TECTONIC EVOLUTION OF EASTERN LAURENTIA: AN INVESTIGATION OF SEDIMENT RECYCLING DURING AND AFTER THE GRENVILLIAN OROGENY" (2025). Theses and Dissertations--Earth and Environmental Sciences. 118.
https://uknowledge.uky.edu/ees_etds/118
Supplemental Table 1.2 Middle Run Formation isotope ratios and ages.xlsx (564 kB)
Supplemental Figure 2.1 Representative detrital zircon grains Kentucky.pdf (1567 kB)
Supplemental Table 2.1 Instrumental conditions.xlsx (11 kB)
Supplemental Table 2.2 Geochronologic analyses - Kentucky basement.xlsx (46 kB)
Supplemental Table 2.3 Geochronologic analyses - Kentucky sandstones.xlsx (370 kB)
Supplemental Table 2.4 Geochronologic analyses - Appalachian sandstones.xlsx (825 kB)
Supplemental Table 2.5 Geochronologic analyses - Bays Formation.xlsx (189 kB)
Supplemental Table 3.1 West Texas igneous isotope ratios and ages.xlsx (29 kB)
Supplemental Table 3.2 West Texas detrital isotope ratios and ages.xlsx (262 kB)
