Earth and Planetary Sciences ETDs

Publication Date

Fall 11-15-2018

Abstract

An 80 m lacustrine sediment core (STL14) from Stoneman Lake, Coconino County, Arizona, contains a sedimentary sequence of at least 1.5 million years, chronicling the complete history of basin infill and recording an extensive and high-resolution archive of climatic and hydrologic fluctuations. Lake levels in this small, internally-drained catchment are sensitive to changes in regional hydrologic balance. Consistent groundwater inflow, even during regionally dry episodes in the lake’s history, has prevented complete desiccation of the lake and sustained continuous lacustrine deposition except for one soil horizon. Multiproxy analysis of sedimentological indicators including lithofacies, color, wet bulk density, magnetic susceptibility, preliminary XRD mineralogy and scanning XRF geochemistry (Ti and Ca), and palynology suggest changes in lake depth, productivity, alkalinity, and clastic influx vary cyclically with global ice age cycles. Preliminary age-dating (14C-AMS and tephrostratigraphy) allows correlation of facies interpretations in STL14 to global climate stratigraphy provided by the LR04 marine benthic δ18O stack (a record of continental ice volume and deep ocean temperature). Lacustrine facies cyclicity is in phase with both global and regional paleoclimate at millennial to orbital timescales and extends into the early Pleistocene. This study provides a stratigraphic framework and sedimentologic background for further paleoclimatological analyses as well as a preliminary orbital-timescale paleoclimate reconstruction for the interval spanning the last 800 ka (MIS 1 to 20).

Degree Name

Earth and Planetary Sciences

Level of Degree

Masters

Department Name

Department of Earth and Planetary Sciences

First Committee Member (Chair)

Peter Fawcett

Second Committee Member

R. Scott Anderson

Third Committee Member

Maya Elrick

Fourth Committee Member

Gary Weissmann

Language

English

Keywords

Quaternary, lacustrine core, facies analysis, multiproxy, lake basin, Southwest

Document Type

Thesis

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