Fig. 5From: Magnesium silicate chimneys at the Strytan hydrothermal field, Iceland, as analogues for prebiotic chemistry at alkaline submarine hydrothermal vents on the early EarthPowder X-ray diffraction patterns of the sample S1(tip) (A), S1(tube) (B), S2(top) (C), and S2(bottom) (D). Most of the reflections may be assigned to aragonite (a), calcite (c), and saponite (s)Back to article page