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Abstract. Expedition 364 was a joint IODP and ICDP mission-specific platform (MSP)expedition to explore the Chicxulub impact crater buried below the surface ofthe Yucatán continental shelf seafloor. In April and May 2016, thisexpedition drilled a single borehole at Site M0077 into the crater's peakring. Excellent quality cores were recovered from ∼505 to ∼1335mbelow seafloor (mb.s.f.), and high-resolution open hole logs were acquiredbetween the surface and total drill depth. Downhole logs are used to imagethe borehole wall, measure the physical properties of rocks that surround theborehole, and assess borehole quality during drilling and coringoperations. When making geological interpretations of downhole logs, it isessential to be able to distinguish between features that are geological andthose that are operation-related. During Expedition 364 some drilling-inducedand logging-related features were observed and include the following: effects caused by thepresence of casing and metal debris in the hole, logging-tool eccentering,drilling-induced corkscrew shape of the hole, possible re-magnetization oflow-coercivity grains within sedimentary rocks, markings on the boreholewall, and drilling-induced changes in the borehole diameter andtrajectory.