PROBLEMS TO BE SOLVED RELATED TO THE SOUTHERN OKLAHOMA AULACOGEN

The Cambrian geology of the Southern Oklahoma Aulacogen is known from the outcrops in the Wichita Mountains of SW Oklahoma as interpreted by Denison, Gilbert, Powell, Hogan, Price, and Donovan for the post-rift, and from regional geophysics, particularly the seismic sections from COCORP and Keller and McMechan, and the gravity modeling from Coffman etal and Keller and students. These workers have given a good general picture of this Early Cambrian rift including its magmatic character. This character further constrains the possible origins of the magmas and their distribution in the rift crust. It also appears that the rift was over 1000km in length, beginning in the areas of Dallas out to the Uncompahgre. But problems still remain. These are:

1) The Cambrian width of the rift. Two different interpretations are extant: One is the rift width is shown by the gravity anomaly, about 50km, and the other is the rift extends under the Anadarko Basin, about 100km.

2) Were there sediments associated with the rift? None have really been identified.

3) What was the Proterozoic crust like that was being rifted? Was it like the 1.4Ga Arbuckle Crust? Or did it also include a huge old sedimentary basin now seen under the Hollis-Hardeman Basin?

4) The present crustal thickness under the SOA is 40-45km essentially the same as on both sides of the rift. What happened to the mantle under the presumed thinner crust under the active Cambrian rift? The present rift structure seems different than that of neorifts.

5) There is no direct evidence for crustal melting during the rifting process. Why not?

Can we use Earthscope to sort out any of these problems?