Dataset for: A Crust and Lithosphere Model for Alaska and the Adjacent Continental Shelves

Abstract

We present a regional model of the lithosphere structure and crustal thickness for Alaska and adjacent continental shelves based on potential field modelling constrained by thermal analysis and 3D inversion of residual gravity anomalies. The lithosphere model predicts regional northwest directed deepening of the lithosphere-asthenosphere boundary (LAB). The deepest LAB (> 180 km) is located in northern Alaska and the Chukchi Shelf, consistent with cold, strong lithosphere in the northern areas. South of the Denali fault, the LAB topography is complex. Relatively thin lithosphere occurs east of 150 °W, supporting a variable slab shape beneath southern Alaska with a shorter slab segment to the east. The crustal model shows northwest-directed long wavelength thickening (32-36 km), with additional localized trends of thicker crust in the Brooks Range (40 km) and in the Alaska and St. Elias ranges (50 km). Offshore, 26–28 km thick crust is predicted near the Bearing slope break and 36–38 km in the northern Chukchi Shelf. In interior Alaska, the crustal thickness changes abruptly across the Denali fault, with moderately thick crust north of the fault (34-36 km), and thicker crust south of the fault but that contains sharp crustal thickness variations occurring over short distances. The average crustal density is 2810 ±10 kg∙m-3. Lower density crust (< 2800 kg∙m-3) occurs in the northern Beaufort Shelf and along the offshore Kotzebue Basin and Chukotka Peninsula. Dense crust (2840 to 2910 kg∙m-3) is predicted throughout southern Alaska, with localized low density lenses.