Sediment provenance and correlation of the Upper Cretaceous–Cenozoic Colville Foreland Basin, North Slope, Alaska

The Colville Foreland Basin of Alaska records Cretaceous tectonic loading of the ancestral Brooks Range, changes in sediment supply during rifting of the Canada Basin, and Cenozoic rejuvenation of the orogen. Subsurface correlations of non-marine to deep-water clinothems demonstrate that multiple northeast-prograding transgressive–regressive cycles occurred in response to these factors. However, correlation of outcrops to the subsurface, particularly lithologically similar deep-water deposits, can be challenging where chronostratigraphic information is lacking. We present new detrital zircon (DZ) U–Pb data (>50 samples) from Upper Cretaceous–Cenozoic strata and calculate maximum depositional ages to understand provenance changes and test emerging sequence stratigraphic models for the Colville Basin.

Results show that the Coniacian to mid-Campanian clinothems of the lower and middle Prince Creek and Schrader Bluff formations mark a basin-wide increase in reworked volcanic ash from the Okhotsk–Chukotka Volcanic Belt (OCVB), with mid-Cretaceous DZ ages comprising >70% and 25–80% of DZ, respectively. Following a major transgression, mid-Campanian–Paleocene clinothems of the upper Prince Creek and Schrader Bluff formations have reduced Late Cretaceous DZ (0–20%) due to cessation of OCVB activity, and increased Paleozoic and Permian–Triassic DZ attributed to sediment recycling from the older Chukotka-sourced Nanushuk Formation. Cenozoic strata are relatively devoid of contemporaneous DZ and denote rejuvenated Brookian Orogen deformation and local transport into the Colville Basin. Paleocene clinothems of the Sagavanirktok and Canning formations consists of >80% Paleozoic DZ sourced from central Brooks Range allochthons. Eocene–Miocene clinothems have variable DZ distributions with diminishing Mesozoic and increasing Precambrian DZ up-section. During this time, contractional deformation propagated northward and parautochthonous rocks of the eastern Brooks Range were rapidly uplifted, causing eastward tilting of the basin. These temporally consistent DZ provenance signatures prove useful for correlating genetically related sequences, allowing us to apply outcrop observations to coeval strata in the subsurface.