Abstract: Abstract: Red Wing Creek Field, North Dakota--Cryptoexplosion Structure of Subsurface Origin Rather Than Meteor-Impact Structure

L. W. Dan Bridges

In 1905, Branca and Fraas introduced the term "cryptovolcanic" for a small, complex structure in the otherwise flat-lying Steinheim basin in southern Germany. This structure is a circular depression, 1.5 mi (2.4 km) in diameter with an intensely deformed central uplift which is partly covered with siliceous sinter deposited by hot springs. No trace of volcanic material is present. In 1933, Bucher described six cryptovolcanic structures in the United States: Wells Creek basin, Tennessee; Serpent Mound, Ohio; Jeptha Knob, Kentucky; Kentland dome, Indiana; Decaturbille dome, Missouri; and Upheaval dome, Utah. The idea that these might be meteor-impact structures apparently did not occur either to Bucher or to Branca and Fraas. In 1959, Dietz coined the term "cryptoexplosion" structure which I think is most appropriate. Since 1965, most of Bucher's "cryptovolcanic" structures have been redescribed and their origin attributed to the impact of meteorites.

Red Wing Creek field is an intensely deformed subsurface structure located in T148N, R101W, North Dakota, near the center of the Williston basin. It is sombrero-shaped with a circular central uplift ringed by a synclinal depression, which in turn is flanked by an outer-rim uplift. The central uplift, which covers a little more than a section, is estimated to contain 100 million bbl of recoverable oil in the Mississippian Mission Canyon Formation. Parson concluded that this is a "meteor impact structure of Jurassic age." Brenan, Peterson, and Smith considered that the most likely explanation for the structure was hypervelocity meteor impact and rebound, which created the structure in several seconds.

It seems more likely to me that the Red Wing Creek structure began in Permian time with structural arching near the intersection of two major wrench faults. Gradually, a small wedge-shaped block was forced upward and hot springs replaced the Charles salt within this central wedge and sealed over the escaping gases and water. In Permian-Triassic time, subsurface gas pressure increased until there was an explosion similar to a volcanic eruption. This explosion further uplifted the central core, and created the breccia, shatter cones, and rim syncline. Gravity sliding away from the central core in Jurassic time created a younger, smaller depression around most of the central core.

Sawatzky described Viewfield in Saskatchewan and Hartney in Manitoba as two other subsurface astroblemes in the Williston basin. Perhaps there are others. If these features actually are proved to be associated with regional wrench faults and exploding subsurface gas, we should have a better concept for future exploration of this type of structure and related structures.

AAPG Search and Discovery Article #90969©1977 AAPG-SEPM Rocky Mountain Sections Meeting, Denver, Colorado