Paper No. 3
Presentation Time: 9:30 AM
HOLOCENE DEPOSITIONAL HISTORY OF HABERER’S SALT MARSH IN NORTH-CENTRAL KANSAS
Salt marshes and springs are abundant in north-central Kansas and have played a unique role in the historic and economic history of the region. This study examines the Holocene history of the Haberer’s Salt Marsh (39° 0'37.88"N, 98°57'19.20"W) located in a tributary paleovalley down-cut into the Cretaceous Dakota Formation immediately north of the Saline River. The marsh is characterized by saline artesian flow from a salt-rich member of the Dakota. Given the setting of the salt marsh, it has the potential to be an archive of paleoenvironmental data, and our objective was to determine if such a record is extractable from the sediments. Core and auger sampling indicated about 5 m of marsh deposits above the bedrock. A radiocarbon age determined on bulk organics from a sample collected in basal sediments during an earlier study was 9280 +/- 210 RCYBP (c. 10,485 Cal YBP; δ13C = -23.8‰). A recent sample collected from a depth of 1.27 m and separated into two organic components yielded ages of 5000 +/- 50 RCYBP (peat; c. 5730 Cal YBP; δ13C = -24.8‰) and 5380 +/- 30 RCYBP (organic sediment; c. 6200 Cal YBP; δ13C = -23.7‰). Multiple proxies were used to characterize the history of the salt marsh. Fifteen samples collected 94-500 cm depth were analyzed for percent organic matter, total carbon, magnetic susceptibility, pH, water content, electrical conductivity, mineralogy, and total charcoal count, with a botanical microfossil investigation underway. The marsh stratigraphy consists of two distinct zones: c. 5 m to 2.2 m depth, and 2.2 m to c. 1 m depth. Initial rapid sedimentation of the paleovalley occurred, starting at 11 ka but then slowed shortly before c. 5.7 ka. A second brief pulse of rapid sedimentation occurred immediately above 2 m in depth, with apparent slow sedimentation thereafter. Total charcoal, carbon, and percent organic matter levels are significantly higher above 2 m in depth, which is interpreted as a relatively stable period of with little change from c. 5.7 ka to present. The middle Holocene (6-5 ka) was a time of climate shift and associated hydrologic change in the rivers of the central Great Plains.