GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 1.2 GNGTS 2024 Fig. 1 - Locaton of the magnetc survey lines and te lines acquired in Martgnano Lake. Results The magnetc anomaly map resultng from the survey, shows that the Martgnano magnetc anomalies are due to the presence of a negatve magnetzaton contrast with the surrounding volcanic rocks; the primary dipolar structure of the magnetc intensites observed at the southern and northern borders of the lake (negatve magnetc intensity lobe at point A and positve one at point B, Fig. 2) is atributed to the contrast in magnetzaton among the hydromagmatc products originatng from the Martgnano center, mostly consistng of stratfed and cross-stratfed tufs with alternatng fne-ash rich and coarse-ash to fne-lapilli rich horizons, the underlying structure of the maar, and the pre-maar compositon, predominantly consistng of alternatng pyroclastc deposits and lava fows from the SVD's actvity. Nicolosi et al. (2019) estmated a bulk magnetzaton of 3 A/m for SVD products. This magnetzaton value surpasses the average values recorded from outcrops of the hydromagmatc products found at the Martgnano lake by an order of magnitude, resultng in a signifcantly lower measurement. This contrast can also be considered representatve for the diatreme and crater infll products.