Davis Bank Petrogenesis, Vitória-Trindade Chain, South Atlantic: Volatiles Role (H2O and CO2) in the Davis Bank Magmatic Evolution

Isotopic constraints on Davis bank, Vitória-Trindade Ridge: A Revised Petrogenetic Model

“…As outlined before, Davis Bank is not only the most voluminous volcanic building of the VTR, but also displays several characteristics distinct from the other seamounts and the Trindade-Martin Vaz archipelago. Isotopic analyses here presented for the Davis Bank, alongside whole-rock data and mineral chemistry (Jesus et al, 2019), confirm those suggestions. For instance, according to Jesus et al (2019), Davis Bank lavas show enrichment in incompatible elements (La/Sm N ca.…”

“…Isotopic analyses here presented for the Davis Bank, alongside whole-rock data and mineral chemistry (Jesus et al, 2019), confirm those suggestions. For instance, according to Jesus et al (2019), Davis Bank lavas show enrichment in incompatible elements (La/Sm N ca. 4.1 and La/Yb N ca.…”

“…To provide further information on the alkaline magmatism of the Vitória-Trindade Ridge, we here present new geochronological and isotopic data of samples from the volcanic episode that led to the formation of one of the largest physiographic features of the VTR alignment, the Davis Bank. We report new 40 Ar/ 39 Ar age data, Sr-Nd-Pb isotopic compositions and geochemical compositions from Davis Bank in combination with literature data (Halliday et al, 1992, Marques et al, 1999, Fodor and Hanan, 2000Siebel et al, 2000;Peyve and Skolotnev, 2014;Bongiolo et al, 2015;Skolotnev and Peive, 2017;Santos et al, 2018a;Jesus et al, 2019;Maia et al, 2021) to elaborate a petrogenetic model that explains the isotopic signature of the studied rocks, as well as to discuss the associated tectonic settings.…”

“…Analytical results of a basanite sample (2.94 wt% K 2 O; LOI = 1.98%; see Jesus et al, 2019 for details) from Davis Bank are presented below. The step heating technique for 40 Ar/ 39 Ar whole rock dating was used.…”

“…The VTR corresponds to a remarkable alignment of alkaline volcanic buildings offshore Brazil with progressively apparent younger ages eastward, which has been interpreted as the track of the Trindade Plume (Thompson et al, 1998;Skolotnev et al, 2011;Bongiolo et al, 2015;Santos, 2016;Santos et al 2018a,b;Skolotnev and Peive, 2017;Maia et al, 2021). Although many geochemical and some geochronological studies have been carried out so far on the main islands of this alignment (Trindade and Martin Vaz; e.g., Halliday et al, 1992;Marques et al, 1999;Siebel et al, 2000;Bongiolo et al 2015;Santos et al 2018aSantos et al , 2018b, both the precise age progression rate along the VTR and an understanding of the nature of each of the magmatic episodes remain elusive, mainly due to the sparse data available for the seamounts (Skolotnev et al, 2011;Peyve and Skolotnev, 2014;Santos, 2016;Skolotnev and Peive, 2017;Jesus et al, 2019;Maia et al, 2021).…”