SDAG Monthly Meeting
Wednesday - April 16 |
Location:
Phil's Barbecue Event Center, Point Loma
3740 Sports Arena Boulevard
San Diego, 92110
Directions:
Phil's Barbecue Event Center is located in the back of the shopping center - behind Phil's BBQ Restaurant.
The venue location is not the restaurant, but the Phil's BBQ Event Center, in the same parking lot.
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6:00pm -
Social hour
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SDAG Monthly Meeting
6:00pm - Happy Hour
6:45pm - Dinner
8:00pm - Program
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6:30pm
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Menu: Pulled Pork and Tri-Tip Sandwich, BBQ Veggie Burger
if pre-registered by the deadline, $5 extra if you did not make a reservation.
Click the SDAG member checkbox on the reservation form if you are a member.
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Cost: $ 50.00 Member; Non-Member $ 60.00; Student $ 25.00
Reservations:
Make/Pay your reservation online by clicking the button below
by 6:00pm Wednesday, April 9
RESERVATIONS CANNOT BE ACCEPTED AFTER by 6pm Wednesday, April 9
(Please note beginning January 2024 all meeting reservations will require on-line pre-payment due to venue costs,
venue contracts, and loss of money due to no shows.)
IF YOU DO NOT PRE-PAY YOUR FOOD RESERVATION, WE CANNOT GUARANTEE YOU A MEAL.
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8:00pm - Program
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"Examination of Middle Cambrian hyoliths from the Manuels River Formation of Avalonian southeastern Newfoundland"
Speaker: NICOLAS OLIVER, Undergraduate Senior, B.S. Geology, San Diego State University
Examination of Middle Cambrian hyoliths from the Manuels River Formation of Avalonian southeastern Newfoundland reveals the presence
of Nevadotheca tenuistriata (Linnarsson, 1871), two forms identified as Angusticornid gen. and sp. 1 and Angusticornid? gen. a
nd sp. 2, Hyptiotheca Bengtson in Bengtson et al., 1990, Tulenicornus gracilior (Matthew, 1895a), as well as four additional,
incompletely preserved, hyoliths. Two possible hyoliths are kept in open nomenclature. These fossils provide further support for
earlier recognized faunal connections of the Avalonian part of Newfoundland with eastern Avalonian Great
Britain, Baltica, Laurentian North America, and Siberia. Nevadotheca tenuistriata is the most common hyolith in the Manuels River
Formation. As most specimens of this species occur in the oxygen deficient dark gray to black mudstone lithofacies, this species
was adapted to such environmental conditions. The species' name tenuistriata has been indiscriminately used for hyoliths of generally
large size (60+ mm); we provide a sound morphologic basis for that concept of that species and for Nevadotheca excellens (Billings,
1872a) and N. princeps (Billings, 1871) which earlier have been mistakenly identified as N. tenuistriata.
Nicolas Oliver has studied geology and paleontology since 2016,
contributing to research both in field and lab settings pertaining to
paleozoic invertebrates, mesozoic dinosaurs and pleistocene
vertebrates. Nick is currently a senior in the undergraduate Geology
program at San Diego State University with plans to pursue a Masters
Degree at SDSU beginning this fall after graduating in the spring. While
attending school Nick works professionally as a Paleontologist for a
private company performing Natural Resource Mitigation to preserve
and document fossil
"Constraining Natural and Anthropogenic Controls on Base of Freshwater and Underground Source of Drinking Water (USDW) In Central San Joaquin Valley."
Speaker: EMILY IMPERATO, MS in Geological Sciences - San Diego State University
Groundwater salinity trends within California's Central Valley are not well constrained. This study identifies the shallowest elevation
of base freshwater (BFW), <3,000 parts per million (ppm) total dissolved solids (TDS), and the shallowest elevation of base of underground
source of drinking water (BUSDW), <10,000 ppm TDS in Fresno, Madera, Kings and Tulare counties. Resistivity and lithologic logs from over
600 oil and gas wells inside and outside of oil fields were analyzed. Resistivity values were identified to represent these groundwater
surfaces: 10 ohms for BFW and 3 ohms for BUSDW. These representative
resistivity values were derived using a temperature and porosity correction for thick (>10 ft) clean sands, specific to the study area.
These chosen values are consistent with previous studies conducted south of the study area in Kern County (Gillespie, 2017). The results
reveal distinct salinity trends north and south of the Kings River drainage divide. South of the divide, BFW and BUSDW are relatively deep,
reaching up to 6,000 feet (ft) below ground surface (bgs) on the eastern margin, rising sharply to near surface elevation in the Tulare
Lakebed basin. North of the divide, BFW and BUSDW are shallower, particularly along a central ridge where these surfaces are about 1,500 ft
higher than at the margins.
Along the western edge of the basin, BFW and BUSDW elevations vary greatly. In general, the observed salinity patterns across the study
area are interpreted to result from spatially variable freshwater recharge from the Sierra Nevada and Coast Ranges. BFW and BUSDW depths
follow the basement along the eastern margin of the study area. We interpret the shallow depth of saline water in the Tulare Lakebed basin
to result from a combination of the low permeability Tulare Lake sediments limiting freshwater recharge and the natural filling and evaporation
cycle of the closed lake basin. In general, BUSDW remains between 500–1,500 ft below BFW, except in the westside subbasin, where historical
(pre-1960s) groundwater pumping was substantial. We propose that historical groundwater pumping of fresh groundwater in the westside subbasin
has caused the BFW to become shallower, but not BUSDW, as evidenced by an increased gap (approximately 2,500 ft) between the two surfaces.
Shallow groundwater pumping is more likely to result in upward movement of the BFW than BUSDW because these groundwater wells target only
shallower freshwater zones and low vertical permeability inhibits upward flow of the deeper, more saline water. Study results suggest that
overall, the dates of geophysical logs are not especially critical when mapping BUSDW, which may change little over time.
I'm Emily Imperato and I hold a Bachelor of Science in Geology from the
University of California, Santa Barbara, and a Master's in Geology from San
Diego State University, which I completed in December 2024. During my
master's program, I interned at the Electric Power Research Institute (EPRI)
on their carbon sequestration team and at Chevron's Bakersfield office,
where I contributed to a carbon sequestration prospect assessment.
For my master's thesis, I focused on salinity mapping in California's San
Joaquin Valley using geophysical logs. I continued this work at the U.S.
Geological Survey (USGS), extending salinity mapping efforts across other
regions of California.
I am very grateful to San Diego Association of Geologists (SDAG) for the student scholarship and I look forward to presenting my master's
thesis work and the work I am doing at the USGS.
"An investigation into the human health risks of lakebed sediments as a proxy for dust chemistry at the Salton Sea"
Speaker: Jordan Jaeger
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Upcoming SDAG meetings - 2025
April 16 - Student research presentations by student scholarship recipients
Second Wednesday - May 14 - SDAG / Geo Institute Joint Meeting (tentative)
June 18 - SDAG / SCGS Joint Meeting
July 16 - Rachel Maxwell on a survey of the Mojave-Sonoran Desert Springs
and their sources. "Is this spring connected to that Aquifer?"
August 20 - Dr. Mario Caputo on Sedimentary Rocks in the Grand Canyon
September 26-28 - SDAG Annual Field Trip, San Andreas Fault in the Wrightwood area, Transverse Ranges (no meeting this month)
October 15 - Todd Wirth on "First report of marine invertebrate megafossils from the Eocene Mount Soledad Fm at Tourmaline Surfing Park"
November 19 - Joint Meeting with AEG Inland Empire Section
December 17 - Traditional Holiday Celebration at the San Diego Natural History Museum with Tom Deméré
Recordings of past meetings
Note: If the video or sound does not play, try using another web browser. Firefox and Chrome may work on some of the videos. MS Edge and Safari are most likely to work.
2/19/2025 A New Seismotectonic Framework for Active Faults in Metropolitan San Diego - Karl Mueller
8/21/2024 Upper Cretaceous through lower Eocene strata in San Diego: Messages for the end-Cretaceous impact, extinctions, and paleoclimates - Dr. Pat Abbott
5/15/2024 Exploring Iceland's Geological Wonders: From a Regional Perspective to a Hiking Expedition - Don Barrie & William Buckley
3/19/2024 Mighty Bad Land: A Perilous Expedition to Antarctica Reveals Clues to an Eighth Continent - Bruce Luyendyk
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