Table 2 Volume estimates of initial and final magmas, as well as of crystallized solid (cumulates) based on the modeled fractional crystallization steps (Table 1).

From: Gravity modeling finds a large magma body in the deep crust below the Gulf of Naples, Italy

Step 1 - from Shoshonitic basalt to trachy-basalt

Initial volume (km3) of Shoshonitic basalt 8,277

Final volume (km3) of trachy-basalt 6,133

Volume (km3) of crystallized solida 2,144

Step 2 - from trachy-basalt to shoshonite

Initial volume (km3) of trachy-basalt 6,133

Final volume (km3) of shoshonite 2,873

Volume (km3) of crystallized solidb 3,260

Step 3 - from shoshonite to latite

Initial volume (km3) of shoshonite 2,873

Final volume (km3) of latite 1,095

Volume (km3) of crystallized solidc 1,778

Step 4 - from latite to trachyte

Initial volume (km3) of latite 1,095

Final volume (km3) of trachyte 425

Volume (km3) of crystallized solidd 669

Total volume (km3) of crystallized solid

7,851

  1. The calculations were carried out in such a way that the final volume of trachyte matched the estimated total volume of differentiated magma erupted by the volcanoes of the Neapolitan area in the past ca. 1.8 Ma.
  2. a = 41.38% clinopyroxene + 28.72% olivine + 21.44% plagioclase + 8.46% Cr-spinel.
  3. b = 56.02% plagioclase + 28.98% clinopyroxene + 6.06% olivine + 5.92% Ti-magnetite + 3.02% Cr-spinel.
  4. c = 41.95% clinopyroxene + 27.99% plagioclase + 19.66% alkali-feldspar + 4.96% Ti-magnetite + 4.66% olivine + 0.78% apatite.
  5. d = 41.64% plagioclase + 27.68% alkali-feldspar + 14.32% clinopyroxene + 7.61% Ti-magnetite + 7.06% biotite + 1.69% apatite.
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