Deep‐penetration heat flow probes raise questions about interpretations from shorter probes

More than 40% of the marine heat flow data collected since the early experiments of Sir Edward Bullard in 1949 were obtained using shallow penetration probes less than 5 m long [ Louden and Wright, 1989]. The common belief that these data are reliable enough to model deep‐seated thermal processes is supported by a few experiments in which heat flow measurements made in the Deep Sea Drilling Program (DSDP) and the Ocean Drilling Program (ODP) were compared to nearby surface heat flow measurements [e.g., Hyndman et al., 1984]. However, thermal measurements made with 18‐m penetrations recently collected on the northern flank of the South‐East Indian Ridge (SEIR) bring a new perspective to this belief. In the study area, measurements of heat flow taken at the surface ( 0–5 m) and measurements taken at greater depths (3–18 m) did not always concur. Investigating this lack of agreement will help address difficult questions about the interpretation of shallow penetration (<5 m) marine heat flow measurements.