News
13.12.2023Paleomagnetic study of volcanic rocks and "red beds" in the Cadí Basin
The CCiTUB, in collaboration with the University of Zaragoza and the IGME (Geological and Mining Institute of Spain), has published the article “Paleomagnetic study of Late-Carboniferous-Permian rocks from the Cadí Basin (Eastern Pyrenees): Tectonic implications” in the journal Tectonophysics.
The article presents the results of a detailed paleomagnetic study of volcanic rocks and "red beds," conducted in part at the CCiTUB Paleomagnetism Laboratory-GEO3BCN, with the participation of its technical manager, Dr. Bet Beamud.
The studied samples belong to the Late Carboniferous-Permian of the Cadí Basin, located on the Orri thrust sheet in the Eastern Pyrenees, an area with limited paleomagnetic studies. Differences in displacement within a thrust sheet can be detected through vertical axis rotations inferred from paleomagnetic methods. In this regard, paleomagnetism has become an important complementary tool in constructing geological sections at both the basin and crustal scales.
Magnetic remanence and age of magnetization
Laboratory measurements involved progressive thermal demagnetization and measurement of remanent magnetization after each demagnetization step. Additionally, rock magnetism measurements were conducted to characterize the magnetic mineralogy carrying the remanence. The magnetic carriers, in both volcanic rocks and "red beds," are magnetite and hematite. Paleomagnetic directions calculated from remanence measurements of both rock types show an SSE direction with a low inclination and a dominant reverse polarity. These results are interpreted as a Permian-age primary magnetization in the "red beds" and as a Late Carboniferous primary magnetization or early remagnetization in the volcanic rocks.
The obtained results have demonstrated an absence of regional vertical axis rotations in the Cadí Basin, thus contributing to a better understanding of the deformation experienced by this area during the growth of the Pyrenees.
Funding
This work has been supported by the grants from the projects PID2020-114273GB-C22, PID2019-108753GB-C22, and PID2019-104693GB-I00 funded by MCIN/AEI/10.13039/501100011033, “ERDF Away of making Europe,” and “ESF Investing in your future.”