Sediment Provenance Changes During the Evolution of the Upper Cretaceous–Cenozoic Colville Foreland Basin, North Slope, Alaska

Session: Advances and Applications in Geochronology for Interpreting Stratigraphic and Basin Records (Posters)

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Abstract:

Brookian strata of the Colville Foreland Basin record the Jurassic–Early Cretaceous initiation of the ancestral Brooks Range, flexural response to the tectonic load, and subsequent Cenozoic rejuvenation of the orogen. Previous detrital zircon (DZ) U-Pb provenance data from the Albian–Cenomanian Nanushuk-Torok clinothem indicate a voluminous longitudinal sediment influx of Permian–Early Cretaceous DZ from the Russian Chukotka Orogen. Prevalent mid-Cretaceous DZ in the subsequent Turonian Tuluvak-Seabee clinothem are attributed to continued longitudinal transport of Chukotka sediment and increased airfall ash from the Okhotsk-Chukotka Volcanic Belt (OCVB).

We present new DZ data from >50 sandstone samples from Upper Cretaceous–Cenozoic strata of the eastern North Slope and calculate maximum depositional ages (MDAs) to test sequence stratigraphic and provenance models for the remaining basin history. Recent subsurface correlations and geologic mapping demonstrate that nonmarine-to-deepwater facies of the Coniacian–Paleocene Prince Creek-Schrader Bluff-Canning formations, and the Paleocene–Miocene Sagavanirktok-Canning formations each comprise three northeast-prograding transgressive-regressive cycles (i.e., both systems have lower, middle, and upper sequences).

Onset of the Prince Creek-Schrader Bluff system marks an abrupt basinwide increase in volcanic detritus, with OCVB-age DZ comprising >70% and 25–80% in the lower and middle sequence, respectively.  Following a major Campanian transgression, the upper Prince Creek-Schrader Bluff sequence and coeval Maastrichtian–Paleocene units to the east have significantly reduced Late Cretaceous DZ (0–20%), and increased Paleozoic and notably Permian–Triassic DZ that are attributed to recycling of Chukotka-sourced Nanushuk Formation or older Lower Cretaceous units to the south.

The Cenozoic Sagavanirktok system is relatively devoid of contemporaneous DZ and documents the decisive onset of rejuvenated deformation in the Brookian Orogen and increase in locally derived sediment into the Colville Basin. The Paleocene lower Sagavanirktok sequence consists of >80% Paleozoic DZ derived from allochthons of the central Brooks Range. The Eocene–Miocene middle and upper sequences have variable DZ distributions that are a mix of age populations present in underlying strata, with diminishing Mesozoic and increasing Precambrian DZ upsection. During this time, contractional deformation propagated northward, the eastern Brooks Range was rapidly uplifted, and a prominent forebulge exhumed the Upper Cretaceous stratigraphy in the western Colville Basin. These temporally consistent DZ provenance patterns can be used to correlate genetically related sequences where other chronostratigraphic information is lacking.