About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 48 (1964)

Issue: 3. (March)

First Page: 269

Last Page: 291

Title: Paleomagnetic Correlation of Units Within Chugwater (Triassic) Formation, West-Central Wyoming

Author(s): M. Dane Picard (2)

Abstract:

Directions of magnetization in the Triassic Chugwater Formation can be divided into two distinct groups nearly opposed to each other. These "normal" and "reversed" groups of Previous HitmagneticNext Hit directions have been used to correlate units within the Chugwater Formation in west-central Wyoming. Twenty-four possible Previous HitmagneticNext Hit "events" were noted; twelve of these appear to be caused by a reversal of the earth's Previous HitmagneticNext Hit field. Insufficient data are available to determine whether the other Previous HitmagneticNext Hit events record a reversal of the earth's Previous HitmagneticNext Hit field.

Local correlation between two sections 4.5 miles apart (northeast Thermopolis and south Thermopolis) indicates that the paleomagnetic correlation is not as precise as the lithologic correlation, but the two types of correlation do not conflict. Both types of correlation lines are approximately local "time-lines."

Regional correlation between stratigraphic sections along a cross section of 216 miles indicates that the paleomagnetic correlation lines are approximately "time-lines." Other results of the paleomagnetic correlation are: (1) lateral or vertical changes in rock type do not affect the Previous HitmagneticNext Hit directions within some intervals; (2) Previous HitmagneticNext Hit events differ in duration; (3) the number of Previous HitmagneticTop events that can be correlated decreases as the distance between sections increases; and (4) the intensity of magnetization appears to be the same in normally and reversely magnetized samples.

The intensity of magnetization in the samples from the Chugwater Formation generally varies according to rock type. From least intense to most intense, this variation is: (1) drab siltstone and sandstone; (2) red, very fine-grained sandstone; and (3) red siltstone and poorly sorted siltstone. No significant relation between intensity of magnetization and bedding type has been noted.

Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Watermarked PDF Document: $14
Open PDF Document: $24

AAPG Member?

Please login with your Member username and password.

Members of AAPG receive access to the full AAPG Bulletin Archives as part of their membership. For more information, contact the AAPG Membership Department at [email protected].