How Did The Seeds Get There? Ruppia cirrhosa Ecology, Depositional Context and Accurate Radiocarbon Dating at White Sands

Summary

This is an abstract from the "Geoarchaeology in First Americans Research, Part 1" session, at the 90th annual meeting of the Society for American Archaeology.

The stratigraphic and geomorphic contexts, and ultimately the chronometric determinations, at White Sands Locality-2 (WHSA-2) are topics of controversy that stem from conflicting interpretations of the processes that deposited the Ruppia seeds within the paleo-Lake Otero footprint site. Some studies have characterized the eastern shoreline as a stable lake margin where Ruppia plants grew in situ in shallow water. In contrast, our interpretation depicts the shoreline as an unstable, dynamic lake margin to which Ruppia seeds, impacted by the hard water effect, were transported from deep-water, offshore growth beds during storm events and deposited on the lake shore in seed balls. These unusual aggregates, known to mix seeds of wide-ranging ages, were gradually broken apart by several cycles of wave action and erosion and redeposited in layers. At WHSA-2, other researchers have claimed to focus their radiocarbon dating solely on seeds from layers and not from seed balls, ostensibly to avoid mixing issues. Yet, how do they know that the seeds they dated did not come from disaggregated seed balls? In this presentation, we will delve into both the ecology and the depositional context of Ruppia and discuss why the seeds at paleo-Lake Otero are problematic materials for radiocarbon dating.

This Resource is Part of the Following Collections

• Geoarchaeology in First Americans Research, Part 1   •
• Society for American Archaeology 90th Annual Meeting, Denver, CO (2025)

Keywords

Record Identifiers

Abstract Id(s): 53064