convection in the middle Cretaceous pushing the ocean floor upward and sideward. When Resolution Guyot rose above sea level, karst processes began to impact the platform. The platform became irregular and part of it was eroded away; calcrete crusts, carbonate pinnacles, cavities, caverns containing speleothems and sinkholes formed and exist to this day. At this stage, Resolution Guyot would have resembled a makatea island. This karstic episode did not last for long, perhaps several hundred thousand years, but structures left by the karstic phase such as sinkholes and carbonate pinnacles can still be seen on the surface platform of Resolution Guyot. During periods of emergence, freshwater flowed through and modified the carbonates. Drowning and post-drowning evolution Resolution Guyot drowned either about 99 ± 2 million years ago or during the Maastrichtian (72.1 ± 0.2 to 66 million years ago), although a hiatus in shallow carbonate deposition appears to date back to the Albian that may reflect a long pause in deposition or increased erosion. The end Albian period was characterized by widespread cessation of carbonate sedimentation across the western Pacific. It is possible that carbonate sedimentation later continued until Campanian (83.6 ± 0.2 – 72.1 ± 0.2 million years ago)-Maastrichtian times. The platform was certainly submerged by Pliocene (5.333 – 2.58 million years ago) times. Other carbonate platforms in the Pacific drowned especially at the end of the Albian, for unknown reasons; among the proposed mechanisms are overly nutrient rich or turbid waters, the disappearance of reef-forming species and a subsequent failure of them to return, and overly fast sea level rise. Resolution Guyot was never far enough south to end up beyond the Darwin point at which carbonate deposition stops. The Resolution Guyot platform rose above sea level before the drowning, and there is no indication that carbonate deposition recommenced when the platform subsided; similarly other Mid-Pacific Mountains emerged before drowning. There is disagreement about whether Resolution Guyot was close enough to the equator and nutrient rich equatorial waters to drown at the time when carbonate sedimentation ceased. After the drowning, crusts formed by ferromanganese and by phosphate-modified rocks developed on exposed surfaces at Resolution Guyot. Several different layers of phosphate modification have been observed during the Albian alone and this process may have begun when the platform was still active; water within the rocks may have triggered phosphatization at this stage. The ferromanganese deposition probably only began in