Paleomagnetism of the Early Proterozoic Sioux Quartzite, Southwestern Minnesota. Implications for Correlating Quartzites of the Baraboo Interval. (Chapter N)

摘要

Paleomagnetic studies of the Early Proterozoic Sioux Quartzite in southwestern Minnesota have revealed a highly stable, single-component magnetization that is primarily carried by diagenetic hematite. The magnetization is tentatively interpreted as having preceded regional tilting. On the basis of isotopic ages and existing Early Proterozoic APW (Apparent Polar Wander) data for North America, the structurally corrected Sioux paleopole, located 101 deg W. and 16 deg N. implies a diagenetic age of 1,700-1,650 Ma for the Sioux. The authors propose that the Baraboo and possibly the Flambeau and Waterloo Quartzites in Wisconsin may be related to the Penokean orogeny, whereas the Sioux and possibly the Barron Quartzites are related to the younger Great Plains orogeny.