MagNetZ With Natalia Gauer Pasqualon  (2023/08/30) - New Volcanological Record from Trindade Island
Channel: MagNetZ
Date: 2023-10-28

New Volcanological, 40Ar/39Ar Ages and Paleomagnetic Record from Trindade Island and Stratigraphic Implications

The video is also available for download at: https://earthref.org/ERDA/2722/
and can be referenced with the doi: 10.7288/V4/ERDA/2722

Title: New Volcanological, 40Ar/39Ar Ages and Paleomagnetic Record from Trindade Island and Stratigraphic Implications
Author: Natalia Gauer Pasqualon from the University of Hawaii at Manoa, USA

Unrevealing the stratigraphy of volcanic systems is fundamental to understanding their eruptive history and requires a multiproxy approach for the accurate correlation and interpretation of deposits. We present novel volcanological, 40Ar/39Ar ages and paleomagnetic data for the volcanic rocks of Trindade Island, located at ~1.260 km from the Brazilian coast in the South Atlantic Ocean. The volcanic history of Trindade Island is important because it is the youngest volcanic terrain in Brazil and part of a submarine chain that represents the most recent plume induced alkaline manifestation beneath the South American plate. Our results suggest Trindade Island underwent two main phases of volcanism. The first phase (3.9-1.5 Ma) of dominant phonolitic composition formed the Trindade Complex and Desejado Formation, with eruptive styles ranging from phreatomagmatic/Surtseyan to Vulcanian. The second phase (1.2-0.059 Ma) formed the nephelinitic monogenetic centers Morro Vermelho, Valado and Paredão Volcano Formations through Hawaiian and Strombolian styles. The new ages imply on a revised stratigraphy for the youngest units of Trindade Island, with partial overlap between them. The revised chronology integrated to the paleomagnetic directional data evidence that Trindade Complex formed during Gauss normal chron (D= 359.98; I= -49.04), Valado and Paredão Volcano during Brunhes normal chron (D= 16.56; I= -41.46 and D= 27.65; I= -52.25, respectively), while Morro Vermelho registers a transitional field at the late stages of Matuyama chron (D= 4; I= -6.2), with paleodirectional records at site-level of normal polarity (D= 52.15; I= -27.7) within the reverse Matuyama interval.


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00:00 - Intro
01:05 - Presentation
25:45 - Questions
34:31 - Announcements