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Download a zip file that includes all the web pages and downloadable files from the student materialsFor the Instructor
These student materials complement the Coastal Processes, Hazards and Society Instructor Materials. If you would like your students to have access to the student materials, we suggest you either point them at the Student Version which omits the framing pages with information designed for faculty (and this box). Or you can download these pages in several formats that you can include in your course website or local Learning Managment System. Learn more about using, modifying, and sharing InTeGrate teaching materials.542 Million Years of Sea Level Change: Exxon's Sea Level Reconstruction
The "Exxon Sea Level Curve" shows high-frequency oscillation. Why?
As we have mentioned elsewhere, the "volatility" or dynamic nature of sea levels - especially those highlighted by the "Exxon Curve" or "Haq et al. curve" is again apparent.
Whether sea level change is periodic (daily) or if it varies repetitively over 1000s of years, the term volatility refers to the frequent changes in sea level (denoted by the up-down-up-down pattern) which suggests repeating changes in processes controlling sea levels.
When you see this pattern, regardless of temporal scale, it's almost as if some process gets switched on and off. The repetitive nature of high-frequency cycles suggests tectonic activity might not be the major driving factor for the high-frequency oscillation, even though it might influence the major patterns of sea level change (i.e., the Wilson Cycles).
Through your exploration, you might have already observed that Phanerozoic sea level curves, demonstrated by the Hallam curve, are averaged and highlight longer-term trends at the expense of high-resolution data - a point that was also previously established in this unit.
Nevertheless, overall similarity between the two curves is significant with regard to general sea level trends. There are, of course, some differences that scientists are exploring even now through higher-resolution studies.
At this juncture, it is important to ask: What is responsible for the extreme volatility in sea levels as suggested by proxy data?
