rsvp dating singles - Zircon fission track dating humphreys

A fundamental problem in reconstructing the post-Cretaceous landscape evolution is that erosion has removed most of the Cenozoic sedimentary record on the Colorado Plateau.

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Thermal history modeling of top basement samples reveals Late Cretaceous heating to temperatures of at least 90 °C, implying sedimentary burial to ∼3 km, followed by cooling throughout the latest Cretaceous to Eocene.

However, AHe ages (38–31 Ma) indicate minor reheating to 40–80 °C for these samples in the late Eocene to Oligocene.

They are ideally suited to investigate the Cenozoic history of the Colorado Plateau.

However, care must be taken in evaluating these data, because the geothermal gradients might be strongly influenced by the presence of mid-Cenozoic magmatism (see distribution of volcanic rocks in Hunt, 1956; Roy et al., 2009; volcanic pattern in Nelson and Davidson, 1998) and later Neogene basaltic magmatism (e.g., van Wijk et al., 2010) within and along the plateau boundaries.

The youngest sediments still preserved today are remnants of the Cenomanian–Campanian Dakota Sandstone and Mancos Shale (e.g., Williams, 1964; Jamison and Stearns, 1982).

A latest Cretaceous–Cenozoic sedimentary record is missing on the Uncompahgre Plateau.

Numerous thermochronological studies have been applied to the southwestern part of the Colorado Plateau (e.g., Dumitru et al., 1994; Kelley et al., 2001; Flowers et al., 2008), and some data exist for the central parts (Stockli et al., 2002; Hoffman et al., 2011; Murray et al., 2016). (2014) presented a few ages and models related to the highly debated origin of the Unaweep Canyon, which cuts across the Uncompahgre Plateau.

Less attention has been devoted to the northeastern part of the plateau, including the Uncompahgre Plateau. In this paper we present new thermochronological data that help constrain the timing and magnitude of the Uncompahgre Plateau uplift.

Zircons from the La Sal Mountains laccolith gave an Oligocene U-Pb crystallization age of 29.1 ± 0.3 Ma.

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