MagNetZ With Matteo Maron (2023/02/22) - Rock Magnetism as an Indicator of Paleoclimatic Conditions
Channel: MagNetZ
Date: 03/04/2023

Rock Magnetism as an Indicator of Paleoclimatic Conditions in the late Norian-early Rhaetian (Late Triassic): The Example of the Pignola-Abriola Section (Lagonegro Basin, southern Italy)

The video is also available for download at: https://earthref.org/ERDA/2552/
and can be referenced with the doi: 10.7288/V4/ERDA/2552

Title: Rock Magnetism as an Indicator of Paleoclimatic Conditions in the late Norian-early Rhaetian (Late Triassic): The Example of the Pignola-Abriola Section (Lagonegro Basin, southern Italy)
Author: Matteo Maron from the University “G. d’Annunzio” of Chieti-Pescara, Italy

The late Norian to early Rhaetian (Late Triassic) interval is characterized by an important biotic crisis that involved marine and terrestrial fauna (mainly conodonts, ammonoids, bivalves and theropods), possibly linked to a climate perturbation that began in the Sevatian (upper Norian, ~216 Ma) and persisted up to the Rhaetian (~205.7 Ma). In order to understand the nature of this crisis, we investigated the rock magnetic and geochemical properties of the Upper Triassic sedimentary marine section of Pignola-Abriola (Lagonegro Basin, Southern Italy). We performed experiments on magnetic susceptibility (χ) and on natural, anhysteretic and isothermal remanence (NRM, ARM, IRM), compared then to geochemical data, obtaining the necessary parameters we used for our paleoclimatic investigation. We identified at least two episodes of increase in relative quantity of hematite in the late Norian (Sevatian 1) and in the earliest Rhaetian, suggesting enhanced subaerial oxidation of iron minerals. A progressive increase in weathering starting from the late Norian seems to be confirmed by the results we obtained from geochemical analyses and is coherent with the Sevatian Warming Episode and the increase of 87Sr/86Sr ratios. The second, rapid increase of weathering occurs just above the Norian/Rhaetian boundary and is possibly related to the emplacement of a large igneous province (LIP), as the decrease of the 87Sr/86Sr and 187Os/188Os ratios in the lower Rhaetian seems to suggest. The high quantities of carbon dioxide emitted from a LIP could also explain the negative 13Corg excursion recognized at the end of the Norian, possibly linked to an anoxic event occurred at the Norian/Rhaetian boundary.

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00:00 - Intro
01:21 - Presentation
28:15 - Questions
38:24 - Announcements