Modern internal waves and internal tides along oceanic pycnoclines: Challenges and implications for ancient deep-marine baroclinic sands: Discussion

Abstract

In his article, “Modern internal waves and internal tides along oceanic pycnoclines: Challenges and implications for ancient deep-marine baroclinic sands” (Shanmugam, 2013), Shanmugam provides a very detailed account of processes involved in oceanic currents. He stresses that he has done this because he is concerned that the misinterpretation of baroclinic sands caused by turbidite deposits could have economic risks for the petroleum industry. As an example of one such possible misinterpretation, he refers to deep-water sands in the Kutei Basin in Indonesia that were described as turbidites by Saller et al. (2006). This is the second time that Shanmugam has questioned our interpretation published in the AAPG Bulletin (Saller et al., 2006). In his 2008 discussion (Shanmugam, 2008) and in his current 2013 article, he asserts that the Kutei deep-water sands might not be turbidites but instead might have been deposited by deep-marine tidal bottom currents. Shanmugam is well known for his decades of opposition to the turbidity-current model for deep-water sand deposition; those interested in this history can find pertinent references under the name Shanmugam in the reference lists of Shanmugam (2008, 2013). Of course, we replied to Shanmugam’s 2008 discussion (Saller et al., 2008a), where we noted that the purpose of our 2006 article was to document the presence of source rock–quality terrestrial organic matter within deep-water sands. Associated shales did not have high organic content. Cores from our deep-water discovery wells contained fining-upward sand layers with abundant fossil terrestrial-plant leaves. The total organic carbon content within some of these sand layers exceeded 5%, and the analysis of oil, gas, and condensate from our deep-water Kutei Basin discoveries indicated a land-plant source for the hydrocarbons, consistent with fossil leaves. We were pleased to present this information to the scientific community, in the hope that it might …