Geology Projects 2011
Sediment Core Analysis: Applications in Petroleum Geology and Groundwater Resources
Faculty Mentors - Dr. Robert Horton
Description coming soon.
In Search of the Laschamp Paleomagnetic Excursion: Ultra-High Resolution Age Control using a Reversal of the Earth's
Magnetic Field 41,000 Years Ago
Faculty Mentor - Dr. Rob Negrini
The Earth's magnetic field reversed itself for a short time period 41,000 years ago. This interesting event has many important
implications for understanding Earth history including:
Evidence for this event has been recovered from magnetic records in lava flows and marine and lake sediments from around the world
(Figure 1), but an unequivocal record has never been found in North America. Over the past two years, work at CSUB has uncovered a
sequence of lake sediments found in a core from Summer Lake, Oregon that appears to have reversed directions and the same magnetic
waveform through time recorded at other sites in the world.
- the development of an ultra-high resolution stratigraphic tool capable of correlating distant sediment
records to within a few hundred years of time
- constraining geophysical models for the origin and evolution of the geodynamo in the Earth's core
- refining estimates of the surface exposure of cosmogenic particles from supernovae and the resulting effect on minor
though important corrections to radiocarbon dating during an important interval of climate change and human evolution
The research team associated with this 2011 Chevron REVS-UP project will refine these early results by sampling the critical
interval in the core and measuring the Earth's magnetic field record in this core using CSUB's paleomagnetics laboratory. This
refined record will be used to tie in the sediments of Summer Lake, Oregon to the time scale established by this event as found
elsewhere in the world thereby setting the stage to use these sediments to test models of global climate change. Also, distinct
patterns in the wanderings of the magnetic pole found in the Summer Lake record may reveal systematic differences in magnetic field
pertubations around the world fundamental to the processes in the core dynamo responsible for aborted reversals.
Reconstruction of the Southern Central Valley’s Paleoclimate Through Correlation
of Weather Station Data and Tree-ring Cores from Mt Pinos.
Faculty Mentor - Dr. Peter Wigand
Several sets of sediment cores have been obtained from Soda Lake, Carrizo Plain. Significant changes have been observed in
salt, charcoal, ostracode and pollen content during the Late Quaternary. These evidence dramatic changes in regional climate.
Modern climate records are clearly inadequate to interpret past climate in the southern Central Valley. However, transfer functions
can be generated that relate modern climate to the response in the growth of trees, and this is revealed in variations in tree-ring
width. A set of tree-rings taken from limber pines on Mt Pinos during the Summer of 2010 seem to span almost 400 years. This data set
plus an additional set to be collected by the students will be used to reconstruct a paleoclimate record at least that far into the past.
Then with such a climatic record we will see if the geologic, and biotic processes evidenced in Soda Lake sediment cores can be
correlated and tentative relationships between these changes and the reconstructed climate record can be made. Students will collect,
prepare, and analyze tree-ring cores, and assess the potential correlation with other paleoclimatic records, e.g. salt, pollen, charcoal,
macrofossils, in the region.
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