The high Sea Level History of Beringia and its correspondence with Super Interglacials and Warm Pliocene at Lake El’gygytgyn, NE Russia – Links to Antarctica

Abstract:

The coastal regions of central Beringia contain a well-studied sequence of marine shorelines consisting of barrier beach sequences and broad coastal plans of superposed marine sediment. These sequences include shorelines associated with 2 Pliocene high sea stands, and lower shorelines dated to MIS 31, MIS 11, and MIS 5e. All of these shorelines correspond with super interglacials identified in the Lake El’gygytgyn paleoclimate record (Lake E), NE Arctic Russia. However, not all super interglacials correspond with a recorded high sea level event in the western Arctic. We argue that most of the high sea stands in central and northern Beringia, especially the NW coast of Alaska, likely require at least the partial demise of Greenland, or WAIS, or EAIS, or some combination of the three. How do we evaluate what melted and why?

MIS 31 was a remarkably warm interval found in the ANDRILL and other marine records around Antarctica. Half a prerecession cycle after this warmth in Antarctica, we see a super interglacial MIS 31 in Lake E. Because of unconformities in the ANDRILL record, MIS 31 still provides the best match with Lake E, but we postulate that other intervals marked by the deposition of diatomaceous ooze in the ANDRILL record may also correspond to many of our interglacials. The challenge has been to determine orbital phasing relationships between warmth in the south and warmth in the north. Here we explore this relationship starting with the striking observation that most super interglacials correspond with extremely low eccentricity, but lagged by ~53kyrs. We explore how orbital conditions may have preconditioned the polar regions to produce a large response during some interglacials; linking changes in polar ice sheet size to sea level and interglacial extremes recorded at Lake E.