Laramide basement blocks of the U.S. Rocky Mountain Province have long been considered the sediment source of the Paleocene-Eocene Wilcox Group, implying that large-scale progradation driven by Laramide uplift induced a transition from carbonate to clastic deposition in the Gulf of Mexico. Detrital zircon U-Pb age spectra from 10 samples collected from the Wilcox Group in south Texas reveal a complex grain assemblage with major age populations at ca. 1800-1300 Ma and 350-50 Ma and minor populations at 1300-950 Ma, 3250-1850 Ma, and 900-400 Ma. Modal data for Wilcox Group sand grain populations from the same region suggest a diverse provenance, including sources from the Cordilleran magmatic arc and subordinate reworked sedimentary rocks. Sediment was primarily derived from a mix of crystalline basement blocks in the U.S. southern Rocky Mountains and northern Mexico, the Cordilleran arc of western Mexico and the southwestern United States, and Mesozoic-Paleogene magmatic rocks of northern Mexico. Secondary sources include recycled strata from Sevier-Laramide basins in the southwestern United States and northern Mexico. Comparisons of detrital zircon U-Pb age spectra show that the Lower Wilcox subunit contains signifi cant magmatic arc-derived sediment, whereas the Upper Wilcox subunit is more enriched in basement and recycled sedimentary detritus. Therefore, the relatively quartzose composition of the bulk detrital assemblages throughout the Wilcox Group of south Texas is not an accurate refl ection of the range of volcanic and basement sources indicated by the associated U-Pb ages, suggesting signifi cant attrition of unstable grains during long-distance (>500-1000 km) transport.

Abstract. Strontium isotope analysis has proven useful in geo-location investigations of organic and inorganic materials and may complement the region-of-origin information provided by hydrogen and oxygen stable isotope analysis. In this study, we analyzed 99 drinking (tap) water samples collected from 95 municipal water systems across the USA to investigate the potential that 87

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New seismic reflection profiles from the Tugrug basin in the Gobi‐Altai region of western Mongolia demonstrate the existence of preserved Mesozoic extensional basins by imaging listric normal faults, extensional growth strata, and partially inverted grabens. A core hole from this region recovered ca. 1600 continuous meters of Upper Jurassic – Lower Cretaceous (Kimmeridgian–Berriasian) strata overlying Late Triassic volcanic basement. The cored succession is dominated by lacustrine and marginal lacustrine deposits ranging from stratified lacustrine, to subaqueous fan and delta, to subaerial alluvial‐fluvial environments. Multiple unconformities are encountered, and these represent distinct phases in basin evolution including syn‐extensional deposition and basin inversion. Prospective petroleum source and reservoir intervals occur, and both fluid inclusions and oil staining in the core provide evidence of hydrocarbon migration. Ties to correlative outcrop sections underscore that, in general, this basin appears to share a similar tectono‐stratigraphic evolution with petroliferous rift basins in eastern Mongolia and China. Nevertheless, some interesting contrasts to these other basins are noted, including distinct sandstone provenance, less overburden, and younger (Neogene) inversion structures. The Tugrug basin occupies an important but perplexing paleogeographic position between late Mesozoic contractile and extensional provinces. Its formation may record a rapid temporal shift from orogenic crustal thickening to extensional collapse in the Late Jurassic, and/or an accommodation zone with a Mesozoic strike‐slip component.

Rapid and high‐magnitude North Atlantic climate oscillations following the Last Glacial Maximum have been correlated to climate change events in western North America. However, the strength of teleconnections between the North Atlantic and the interior of western North America remains poorly understood. We present a U‐series calibrated speleothem record from Timpanogos Cave National Monument, located at 2040 m asl in the Wasatch Mountains of Utah, spanning 13.5–10.6 ka. Additionally, we carried out a climate reconstruction for a coeval glacier advance in the Wind River Range of Wyoming. Our results indicate that between 13.5 and 12.8 ka, the Wasatch was probably first cool and dry and then warmed. After 12.8 ka, our record suggests cool and/or wetter conditions followed by reduced moisture until 11.8 ka, followed by an early Holocene wet period. The Timpanogos record exhibits few similarities with those from the North Atlantic. Climate reconstructions of the Titcomb Basin glacier suggest modest temperature depressions relative to modern (<−3 °C) were necessary to sustain the glacier with a moderate increase in precipitation (>150%). The high‐altitude speleothem record presented here provides a valuable basis for understanding latest Pleistocene–early Holocene glacial episodes in western North America.