a) Location map of hydrothermal chimney crosscutting planar structures measured in the SHCa, represented as oriented orange symbols (satellite image from ©2022 Google Earth). Green lines correspond to 1/10,000 scale hydrothermal chimney alignment mapped over the LAGF area. Map location is shown in Figure 4. b) Rose diagram and stereographic projection represent overall measurements of the hydrothermal chimney crosscutting planar structures. The different sized green arrows indicate the main directions of chimney alignments by relative importance (cf. Fig. 4c).