Skip Links

USGS - science for a changing world

Professional Paper 1747

Sentinel Hill Core Test 1: Facies Descriptions and Stratigraphic Reinterpretations of the Prince Creek and Schrader Bluff Formations, North Slope, Alaska

By Romeo M. Flores, Gary D. Stricker, Paul L. Decker, and Mark D. Myers

Coverpage and link to PDF (11.7 MB)Download Publication
Professional Paper 1747
PDF (11.7 MB)

The Sentinel Hill Core Test 1 well penetrated an intertonguing sequence of (1) the marine Schrader Bluff Formation in the depth intervals 950–1,180 ft and 690–751 ft, which consists of shoreface and offshore deposits that accumulated along a storm-dominated, barred shoreline; and (2) the nonmarine Prince Creek Formation in the depth intervals 751–950 ft and surface to 690 ft, which consists of fluvial channel, crevasse splay, backswamp, and ash fall deposits. The strata range in age from early Campanian to early Maastrichtian.

An erosional contact at a depth of 690 ft at the base of the upper unit of the Prince Creek Formation is interpreted as a major regional sequence boundary, and the overlying conglomeratic fluvial channel deposits are interpreted to have accumulated in a paleovalley. In its more proximal reaches along the Colville River, channels of this paleovalley cut down 75 ft into the lowermost Prince Creek Formation and the uppermost Schrader Bluff Formation. Farther offshore, the equivalent surface to the aforementioned paleovalley appears to be a subtle discontinuity between middle and lower Schrader Bluff Formation shelfal marine strata. Still farther offshore, the equivalent paleovalley surface is interpreted as a marine mass-wasting surface that locally cuts through the lowermost Schrader Bluff Formation and into the underlying Seabee Formation.

Version 1.0

Posted February 2008

Suggested citation:

Flores, R.M., Stricker, G.D., Decker, P.L., and Myers, M.D., 2007, Sentinel Hill Core Test 1—facies descriptions and stratigraphic reinterpretations of the Prince Creek and Schrader Bluff Formations, North Slope, Alaska: U.S. Geological Survey Professional Paper 1747, 31 p.




Previous Lithostratigraphic Descriptions

Prince Creek Formation

Schrader Bluff Formation

New Biostratigraphic Age Constraints

Sequence Stratigraphy and Depositional Setting

Facies Descriptions and Interpretations

Prince Creek Facies


Coarser Grained Facies

Finer Grained Facies

Organic-Rich Facies


Schrader Bluff Facies


Coarser Grained Facies

Finer Grained Facies




References Cited

Part or all of this report is presented in Portable Document Format (PDF); the latest version of Adobe Acrobat Reader or similar software is required to view it. Download the latest version of Acrobat Reader, free of charge or go to for free tools that allow visually impaired users to read PDF files.

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo logo U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information: Contact USGS
Page Last Modified: Thursday, December 01 2016, 04:17:09 PM