“…Third, original carbonate is commonly altered diagenetically, leading to falsely cool temperatures (Pearson et al, 2001); however, this issue is less problematic for short-term events (Crowley and Zachos, 2000). Finally, for planktic d 18 O records it is important to have geographically widespread coverage for a given time slice before making inferences about global surface temperatures (e.g., MacLeod et al, 2005). Nevertheless, despite these drawbacks, benthic paleotemperatures are generally good integrators of globally averaged surface temperatures and rapid changes in d 18 O typically reflect either temperature or ice volume (e.g., Zachos et al, 2001).…”