Understanding the history of global sea level changes has relevance to a wide range of studies in earth sciences. Along with a former graduate student and his colleague Dr. Joann Stock at Harvard, Dr. Molnar proposes to conduct indirect measurements of sea level back to 84 Ma, estimate the errors involved in the technique, and with these constrained ranges of values, prepare interpretations regarding the effects on past climate, global heat flux and sea floor spreading rates. The technique requires calculating the mean age and area of the ocean floor at discrete times in the past. Both calculations require plate reconstructions based on marine magnetic anomalies, and this work has been done over the last several years by Molnar and Stock. From these reconstructions, and from an empirical relationship between seafloor age and depth,"mean depths" can be estimated. Based on the plate configurations and knowledge of continental histories, palinspastic reconstructions of continental lithosphere will provide estimates of the areas of ocean basins. These calculations were done during thesis research by Jose Rosa at 35 and 59 Ma, where he found that sea level was 72 . 26 m and 173 . 56 m above present, respectively. The present award will allow Rosa to continue this work with Stock, and to complete similar analyses at 11, 20, 42, 49, 69, and 84 Ma. While similar work has been done by others (e.g. Kominz, 1984), the precision of his plate reconstructions, his proposed error analysis, and the estimates he will make concerning the effects of 1) seamounts, 2) hot-spot swells, and 3) sediment displacement of ocean water, will result in the most tightly constrained set of sea level estimates yet made.
