Fig. 5: Changes in basalt CaO/Al2O3 compositions along the Western Volcanic Zone (WVZ) of the Gakkel Ridge between the Lena Trough and the Sparsely Magmatic Zone (SMZ). | Nature Communications

Fig. 5: Changes in basalt CaO/Al2O3 compositions along the Western Volcanic Zone (WVZ) of the Gakkel Ridge between the Lena Trough and the Sparsely Magmatic Zone (SMZ).

From: Volcanically hosted venting with indications of ultramafic influence at Aurora hydrothermal field on Gakkel Ridge

Fig. 5

Lower ratios towards either end of the WVZ compared to its center can be attributed to (i) lower degrees of partial melting of the mantle causing less clinopyroxene to contribute CaO to the melt and resulting in reduced melt production51, and/or (ii) high-pressure crystallization of clinopyroxene, leading to CaO depletion in the melt, within a thick lithosphere52. In either case, the data support a restricted thickness of volcanic crust overlying the lithospheric mantle at the Aurora site in the western WVZ (location denoted by vertical arrow). Yellow stars: this study. Gray circles: glass analyses downloaded from the PetDB Petrology DataBase (earthchem.org/petdb).

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