Paleomagnetism and paleogeography of Jurassic radiolarian cherts from the Northern Apennines of Italy
Oriented samples of Jurassic radiolarian chert were collected from the Tuscan domain (continental margin) and the Ligurid domain (oceanic) of the northern Apennines for paleomagnetic study to determine the paleogeographic origins of these rocks. The oceanic rocks are all thermochemically overprinted by a mostly reversed-polarity component of magnetization (B) that was likely acquired during late Miocene regional uplift of the northern Apennines. This component also dominates the lower brittle chert of the Tuscan Cherts, but disappears upsection in the more clay-rich and ductile siliceous marlstones. In addition, the Tuscan Cherts retain an inferred primary magnetization (C), isolated at temperatures between 560 and 660 degrees C, which passes a fold test and shows a polarity stratigraphy. This component indicates a paleolatitude of 11 degrees + or -4 degrees N, and a counterclockwise vertical-axis rotation of 29 degrees + or -9 degrees with respect to the southern Alps of Italy, of 49 degrees + or -8 degrees with respect to Africa, and of 91 degrees + or -8 degrees with respect to Eurasia. Our results suggest that the Tuscan domain was farther south than other deep-water continental margin sections of Adria, and that transcurrent faulting might have played a significant role in the orogenic evolution of the northern Apennines.
Additional publication details
|Publication Subtype||Journal Article|
|Title||Paleomagnetism and paleogeography of Jurassic radiolarian cherts from the Northern Apennines of Italy|
|Series title||Geological Society of America Bulletin|
|Publisher||Geological Society of America|