Geological Investigation of the Mono Basin and surrounding area using ArcGIS Presented by Neil Pearson, Matt Durkee, Saching Mehta, Marvin James, Jeff Lewis 1
1. Geological Investigation of the Mono Basin and surrounding
area using ArcGIS Presented by Neil Pearson, Matt Durkee, Saching
Mehta, Marvin James, Jeff Lewis 1
2. Three Main Tasks Investigate the correlation of Faults and
Springs throughout the region Chart the development of shorelines
through time Hyper spectral remote sensing of the Mono Craters
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3. General Geologic Setting and History The Mono Basin is the
northwestern portion of the Mina Deflection, a seismically active
area characterized by transtension. The transtension has led to the
formation of the basin and is partially responsible for the
volcanaic activity in Long Valley and the Mono-Inyo Craters. The
lake itself was formed ~700,000 years ago when the Long Valley
Caldera errupted and cut off drainage to the Owens River Valley
Since then the recorded highstand was during the last glaciation
12,000 years ago, with lake levels retreating since then 3
4. Faults and Springs Analysis Performed by Matt Durkee and
Sachin Mehta 4
5. Importance of Faults and Springs for Identifying Potential
Geothermal Sites Enhanced Geothermal Sites (EGS) Temperature >
200 C Depth < 3Km Faults are the major controlling feature to
fluid flow within a geothermal region Multiple intermeshing,
overlapping, and intersecting faults increase permeability and flow
Increased fracture density increases probability of geothermal
activity Springs and wells are indicators of potential locations
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6. Importance of Faults and Springs for Identifying Potential
Geothermal Sites Current technology doesnt allow for a high degree
of certainty of EGS without test drilling Drilling is very costly
1-3 million dollars Goal is to develop and analyze geothermal
models and systems to identify the most potential favorable sites
to find shallow hot rock spots and crustal stress conditions with
greater accuracy 6
7. Synthesizing the Connection Between Close Locality of Faults
and Springs for EGS Potential Trace and identify current and
historical locations of theses faults and springs utilizing
different publications Using Arc Map perform combine feature class
then generate near table to assemble all the data together to
perform near table operation Perform Both-Ends operation utilizing
Arc Map to determine potential concentration of active geothermal
wells and springs through increased hydrologic flow with increased
fracture density Perform Dangle operation utilizing Arc Map to
identify where separate faults intersect, where there is a higher
potential for increase hydrologic conductivity and accumulation
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8. Synthesizing the Connection Between Close Locality of Faults
and Springs for EGS Potential 8
9. Synthesizing the Connection Between Close Locality of Faults
and Springs for EGS Potential Goal is for future geothermal site
exploration to increase utilization of past and present fault and
spring publications to be combined with GIS programs that allow for
statistical analysis on how far away springs are from faults and
how both-end and dangle can be applied to determine the EGS of the
underlying hot water reservoirs By determining the fault system and
structural control we can determine with greater accuracy thereby
reducing the exploration costs 9
10. Faults in the Mono Basin The Mono Basin was created by
warping of both tectonic plates and faulting. The Basin holds
various faults with select types and areas that have given rise to
geothermal activity in the basin. The present topography &
depressions/faults of the Mono Basin has occurred throughout the
last three million years 10
11. Mono Basins Geothermal Features Locations of the various
thermal springs in and around the Basin are controlled by fractures
(faults) and tufa ridges. Mono Craters that are in the region are
steam explosion volcanoes that have been plugged by lava flow over
the past millennia. The majority of the 19 steam vents (or
fumaroles) intersect with the faults of the Mono region. We also
identified hydrothermal volcanic vents in the area in order to
assist in possible exploration studies. Fig. 1: Shows average
distance of thermal spring to quaternary volcanic vents in the Mono
Basin Region 11
12. Utilizing ArcGIS to Investigate Geothermal Regions of Mono
Basin Compile data from prior studies and research and map this
data in ArcGIS. Fabricate various layers in order to visually
identify: Specific geologic points of thermal springs, vents, etc.
Inferred regions of these geologic points. Specific
depressions/faults & inferred depressions/faults. Map the
thermal springs from across the basin and surrounding regions in
order to study any spatial correlations between any springs and
faults lines. This will assist in identifying new locations for
geothermal exploration. 12
13. Mapped Geologic Points of Thermal Springs in Long Valley
using ArcGIS13
14. Start & End of Concealed Faults in the Mono Basin
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15. ArcGIS Analyses of Geothermal Regions in Relationship to
Faults in and around the Mono Basin 15
16. Lake Level Mapping Performed by Marvin James and Jeff
Roberts 16
17. Lake Levels at Mono Lake Mono lake has a surface area of
69.5 square miles. It is hydrographically closed meaning that it
only loses water to evaporation. The lake level of Mono Lake
fluctuates a lot. During glacial times the lake may have attained
elevations of as much as 240 meters above its current elevation.
Lake levels started to be officially recorded in 1911. 17
18. Past Climate at Mono Lake Due to the recession of Mono
Lake, previously drowned evidence of past lake fluctuations have
been made evident. Stine, S. Past Climate at Mono Lake. Nature.
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19. Present Climate at Mono Lake Stine, S. Geomorphic,
geographic, and hydrographic basis for resolving the Mono Lake
controversy. Environmental Geology and Water Sciences. Lake levels
before 1940 remained fairly constant with a little fluctuation. In
1941 L.A. County started diverting water from Mono Lake which
caused a sharp decline in the water level from 1940 to 1980. In
1994 L.A. County stopped diverting water from Mono Lake. The water
level is currently at 1944.4 meters. 19
20. AVIRIS (Airborn Visible/Infrared Imaging Spectrometer)
AVIRIS is a sensor developed by NASA and mainly focused on
understanding processes involving global climate change. Optical
sensor that provides 224 spectral channels (bands) with wavelengths
from 400 to 2500 nanometers. We were curious to see if using AVIRIS
imagery would help us see old shorelines of Mono Lake by using
different band combinations. 20
21. Mapping of Shorelines Using AVIRIS imagery. Using different
band combinations we tried to see if there were any visible signs
of shorelines. We used a decorrelation stretch to enhance the image
and make shorelines easier to see. Using aerial imagery to detect
shorelines proved not to be useful and did not provide us any
information. 21
22. Decorrelation Stretch What is it? It can bring out elements
of a photo that were currently invisible to the human eye. It
improves visualization at difficult sites. It removes the high
correlation often found in multispectral data to produce very
colorful composite images. 22
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25. Hyperspectral Investigation of the Mono Craters Performed
by Neil Pearson 25
26. Background on Mono-Inyo Craters Approximately 40 Eruptions
over past 40,000 years Main Chain is silicic volcanics, i.e.
>70% silica 26
27. Background on Hyperspectral imagery Used to determine
mineralogy and vegetation type (But who cares about vegetation)
Collected by the AVIRIS instrument flown by the NASA ER-2 Plane
~15m resolution 27
28. Decorrelation Stretch Image of the Craters 28
29. Spectra and the 2.21micron absorption feature29
30. 30
31. Work to be done includes a linear regression of crater age
with the band depth derived from images 31