Responses of trace elements and optical textures of ultra-deep pyrobitumen to hydrothermal alteration

•Trace elements are innovatively used in the study of hydrothermally altered pyrobitumen.•Hydrothermal minerals cause enrichment of some trace elements in altered pyrobitumen.•The enrichment of trace elements varies with the optical texture change of pyrobitumen.•The hydrothermal activity is not limited to the vicinity of deep faults.