Archaeal lipid diversity, alteration, and preservation at the Cathedral Hill deep sea hydrothermal vent, Guaymas Basin, Gulf of California, and its implications regarding the deep time preservation paradox

•GDGTs and archaeols are heavily degraded in a hydrothermal vent at Guaymas Basin.•The rate is affected by vent temperatures and exceeds that of sedimentary diagenesis.•Archaeal intact polar lipids were detected in sediments exposed to 145 °C porewaters.•The degradation of GDGTs may help explain a preservation gap in the biomarker record.