Updated tops file for Cretaceous and lower Tertiary units, Piceance Basin, northwest Colorado

Introduction

Depths to selected Cretaceous and lower Tertiary stratigraphic units in the Piceance Basin, northwestern Colorado are presented here for 1,563 wells. This file is updated from the Piceance Basin Oil Shale Database with data for additional new drill holes. Also included in this report are elevations for the base of the Long Point Bed of the Eocene Green River Formation for 347 surface locations obtained by determining locations and elevations from published 7 ½-minute quadrangle maps for the Piceance Basin listed in the “Geologic Maps Used to Generate Long Point Control Points” section.

Each entry for the base of the Long Point Bed was obtained at a location where the mapped Long Point Bed intersects a contour line on the published maps. Precision of each elevation is therefore dependent on the precision of the maps and the placement of the mapped contact by the authors.