Provenance analysis of the Ochoco basin, central Oregon: A window into the Late Cretaceous paleogeography of the northern U.S. Cordillera

Abstract

Cretaceous forearc strata of the Ochoco basin in central Oregon may preserve a record of regional transpression, magmatism, and mountain building within the Late Cretaceous Cordillera. Given the volume of material that must have been eroded from the Sierra Nevada and Idaho batholith to result in modern exposures of midand deep-crustal rocks, Cretaceous forearc basins have the potential to preserve a record of arc magmatism no longer preserved within the arc, if forearc sediment can be confi dently linked to sources. Paleogeographic models for mid-Cretaceous time indicate that the Blue Mountains and the Ochoco sedimentary overlap succession experienced postdepositional, coast-parallel, dextral translation of less than 400 km or as much as 1700 km. Our detailed provenance study of the Ochoco basin and comparison of Ochoco basin provenance with that of the Hornbrook Formation, Great Valley Group, and Methow basin test paleogeographic models and the potential extent of Cretaceous forearc deposition. Deposition of Ochoco strata was largely Late Cretaceous, from Albian through at least Santonian time (ca. 113-86 Ma and younger), rather than Albian-Cenomanian (ca. 113-94 Ma). Provenance characteristics of the Ochoco basin are consistent with northern U.S. Cordilleran sources, and Ochoco strata may represent the destination of much of the mid-to Late Cretaceous Idaho arc that was intruded and eroded during and following rapid transpression along the western Idaho shear zone. Our provenance results suggest that the Hornbrook Formation and Ochoco basin formed two sides of the same depositional system, which may have been linked to the Great Valley Group to the south by Coniacian time, but was not connected to the Methow basin. These results limit northward displacement of the Ochoco basin to less than 400 km relative to the North American craton, and

Evolution of the Late Cretaceous Nanaimo Basin, British Columbia, Canada: Definitive provenance links to northern latitudes

“…This paleogeographic reconstruction is also consistent with provenance constraints from Cretaceous strata in the Hornbrook-Ochoco Basin, which suggests the Blue Mountains province was located ~400 km south of its current position, in a position east of the Klamath Mountains and north of the Sierra Nevada in the Late Cretaceous (Surpless, 2015;Surpless and Gulliver, 2018). Gaschnig et al (2017) supported a southern position for the Hornbrook-Ochoco Basin and argued that U-Pb zircon age spectra and Hf isotope signatures indicate a component of sediment derivation from the Coast Mountains batholith (Fig.…”

“…No additional quartzite clast data are available from southwestern Laurentia. Quartzite clasts have also been identified in the Albian to Coniacian Ochoco Basin in central Oregon (Surpless and Gulliver, 2018). Quartzite conglomerate clast detrital zircon populations within the Vizcaino and Ochoco basins are statistically similar and are distinct from those of the quartzite conglomerate clasts analyzed from the Nanaimo Basin (Fig.…”

“…Increasingly sophisticated provenance tools, such as large-n detrital zircon geochronology (Pullen et al, 2014;Matthews and Guest, 2016), detrital thermochronology (Reiners et al, 2005;Reiners and Brandon, 2006;Carrapa et al, 2004), and hafnium isotopic analysis (Bahlburg et al, 2009;Gehrels and Pecha, 2014), permit high-resolution analysis of sediment provenance and basin evolution. There are, however, numerous unresolved issues regarding the spatial and temporal evolution of Mesozoic forearc basins along the North American western margin, including controversies about the timing (Surpless et al, 2006;Haggart et al, 2006, and references therein;Ward et al, 2012;Kent et al, 2020), provenance (Matthews et al, 2017;Surpless and Gulliver, 2018;Orme and Surpless, 2019;Isava et al, 2021), paleogeographic setting (Garver and Davidson, 2015;Mahoney et al, 2016;Sauer et al, 2017a;Stevens Goddard et al, 2018;Trop et al, 2020), and tectonic evolution of different basins along the margin (Wright and Wyld, 2007;Sauer et al, 2017aSauer et al, , 2019Coutts et al, 2020).…”

The forearc ophiolites of California (USA) formed during trench-parallel spreading: kinematic reconstruction of the western USA Cordillera since the Jurassic

“…They are also consistent with a sediment provenance from the North American margin to the east, including its cratonic basement and accreted magmatic arcs (Sierra Nevada, Klamath Mountain, and Idaho) (Dumitru et al, 2015). The Ochoco basin around the accreted Siletzia terrane, is likely the northward continuation of the Great Valley forearc basin (Surpless and Gulliver, 2018).…”

Supplemental Material: Evolution of the Late Cretaceous Nanaimo Basin, British Columbia, Canada: Definitive provenance links to northern latitudes

“…Increasingly sophisticated provenance tools, such as large-n detrital zircon geochronology (Pullen et al, 2014;Matthews and Guest, 2016), detrital thermochronology (Reiners et al, 2005;Reiners and Brandon, 2006;Carrapa et al, 2004), and hafnium isotopic analysis (Bahlburg et al, 2009;Gehrels and Pecha, 2014), permit high-resolution analysis of sediment provenance and basin evolution. There are, however, numerous unresolved issues regarding the spatial and temporal evolution of Mesozoic forearc basins along the North American western margin, including controversies about the timing (Surpless et al, 2006;Haggart et al, 2006, and references therein;Ward et al, 2012;Kent et al, 2020), provenance (Matthews et al, 2017;Surpless and Gulliver, 2018;Orme and Surpless, 2019;Isava et al, 2021), paleogeographic setting (Garver and Davidson, 2015;Mahoney et al, 2016;Sauer et al, 2017a;Stevens Goddard et al, 2018;Trop et al, 2020), and tectonic evolution of different basins along the margin (Wright and Wyld, 2007;Sauer et al, 2017aSauer et al, , 2019Coutts et al, 2020).…”