Abstract
Oxygen-isotope stratigraphy in sediment cores together with carbonate mineralogy and percent carbonate stratigraphies have been used to reconstruct salinity changes, that is lake-level changes of the Great Salt Lake, Utah. For the late Holocene (last 5,500 years), the data suggest the following:
the lake level fluctuated frequently with abrupt changes above and below the modern mean elevation showing high and low extremes greater than those recorded in the historic lake-level curve,there were two periods (minima) of approximately 750 years duration each, when salinities were probably greater and more constant than the modern mean, interpreted as periods of lower average lake levels with fresh-water inflow predominantly from summer precipitation,there were three periods (maxima) of approximately 1500 years duration each, when probable salinities were often less than now but experienced large excursions around the modern mean. These are interpreted as periods of higher lake levels with fresh-water inflow predominantly from winter precipitation,the maxima and minima show an apparent cyclicity and are considered to be controlled by climatically induced changes in weather patterns. The transitions between periods appear to be abrupt occurring on the order of about 100 years.