SDAG monthly meeting
Wednesday - August 20 |
Location:
Sunbelt Publications
664 Marsat Ct # A
Chula Vista, CA
Directions:
I-5 to Chula Vista to Palomar St. Exit east, right on Industrial Blvd., left on Anita St., left on Jayken Way, left on Marsat Ct. Suite A.
OR I-805: Chula Vista Orange Avenue exit, drive west to Third Avenue and turn left, drive south 2 blocks to Anita Street, turn right.
Drive west past Broadway to Jayken Way and turn right. Drive north 1 block and turn right on Marsat Court, go to 664-A on the right.
Park on the street, or in the parking lot in the back.
The Sunbelt location is open-ended to the outside, plan to bring a jacket or sweater in case it gets a little cold after the sun goes down.
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6:00pm -
Social hour
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SDAG Monthly Meeting
6:00pm - Happy Hour
7:00pm - Dinner
8:00pm - Program
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7:00pm
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Menu: Wood-Fired Pizza by San Diego Mobile Pizza with vegetarian and vegan options
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, August 13
RESERVATIONS CANNOT BE ACCEPTED AFTER by 6pm Wednesday, August 13
(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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"Newly Discovered Tetrapod Bones, Insect Trace Fossils, & Eolian Adhesion Structures Upper Pennsylvanian Wescogame Formation, Supai Group, Grand Canyon, Arizona"
Speaker: Dr. Mario Caputo
My ongoing sedimentologic field studies have yielded additional information on the Upper Pennsylvanian Wescogame Formation, one of four lithostratigraphic
units that comprise the Pennsylvanian-Permian Supai Group in the Grand Canyon. A detailed stratigraphic section of the Wescogame Formation, measured and
described along the South Kaibab Trail, revealed tetrapod limb bones, new invertebrate trace fossils, and eolian adhesion structures. The Wescogame is mainly
a ledge- and slope-forming succession of reddish-brown, plane- and ripple-laminated mudstones and silty, very fine- to fine-grained sandstones of fluvial origin.
Interlayered with fluvial strata are two cliff-forming intervals, several meters thick, of tan, very fine- to medium-grained eolian sandstones. Cross-bed sets
therein are no more than 4 m thick and are composed of ripple and grainfall foresets. Distinct eolian ripple laminations form cross-bed bottomsets and possible
interdune strata of variable thicknesses. Conspicuous vertebrate footprints have long been recognized in eolian sedimentary rocks in the Supai Group and in the
Permian Coconino Sandstone in the Grand Canyon. Silicified limb bones reported here in the Wescogame Formation are likely the first body fossils of terrestrial
vertebrates noted from Paleozoic rocks in the Grand Canyon. They are preserved in a lenticular, silty, very fine grained fluvial sandstone.
Wavy, intersecting ridges, < 1.0 cm high, trend consistently down-dip on and parallel to eolian grainfall foresets and are epirelief
structures made just below the sandy dune surface. Their physical form and resemblance to trace fossils of the ichnogenus, Entradichnus, described by others
from the Middle Jurassic Entrada Sandstone of eolian origin in east-central Utah. They have been interpreted as tunnels burrowed by crane-fly larvae that are
known to inhabit modern eolian dune sand.
Common eolian ripple laminations in the Wescogame are interrupted by strata formed by uncommon eolian adhesion ripples. Modern eolian adhesion ripples form
when loose dry sand is blown across a wet sandy surface and is trapped by and adheres to wet sand by capillary attraction. Ripple-like bedforms, a few mm tall,
build up with steep “stoss slopes” facing upwind, in the direction of ripple movement, and with gentle “lee slopes” facing downwind. Such a configuration is in
contrast to that of normal wind (and water) ripples, of which gentle stoss slopes face upcurrent and steep lee slopes face downcurrent in the direction of
ripple movement. As eolian adhesion ripples migrate and climb against the wind, they deposit faint laminations, which mark the angle of climb into the wind.
Because the faint laminations dip downwind, they deceptively appear as normal cross-strata deposited by dunes or larger ripples and are therefore classified
as pseudo-crosslaminations. In the Wescogame Formation, steep “stoss slopes” of eolian adhesion ripples face north-northeast and pseudo-crosslaminations dip
south-southwest in directions that are consistent with north-northeast winds that blew across this part of proto-North America during Pennsylvanian time.
My geologic training from the Department of Geology, San Diego State University (BS geology, 1976) sustained me through a graduate program at Northern Arizona
University (MS, 1980), petroleum exploration with Mobil Oil Corporation (1979-1983), two semesters at the Colorado School of Mines, and 3 years at the University
of Cincinnati (PhD, 1988). With tenure and promotion at Mississippi State University (Department of Geosciences), I coupled advising undergraduates, teaching
soft-rock and general education courses, and overseeing graduate theses on the northern Gulf of Mexico and on San Salvador Island, the Bahamas with adjunct
teaching appointments at Mississippi University for Women and at private Milsaps College in Jackson, MS. I returned to California in 1993 to accept a teaching
post at Mt. San Antonio College (Walnut, CA) (Mt. SAC), where I met Janelle and 30 years later, we were married splendidly by Pat Abbott as officiant. Retiring
from full-time teaching at Mt. SAC in 2010 allowed me to happily accept invitations to teach sedimentary geology at CalPoly Pomona and at San Diego State until
2015. I remain active in the geoscience community as managing editor for Pacific Section, Society for Sedimentary Geology (PS-SEPM); with field work in southern
Utah, southern Nevada, the Bahamas, and Grand Canyon; leading field trips for the Utah Geological Association, GSA, PS-SEPM, SDAG, and the SDSU Geo-alums; and
presenting research at meetings of SDAG, GSA, Desert Symposium in Zzyzx, and Gerace Research Institute on San Salvador Island, the Bahamas.
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Upcoming SDAG meetings - 2025
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" - Marina Village Catalina Room
November 19 - Joint Meeting with AEG Inland Empire Section - Eldon Gath on "San Joaquin Hills, Santa Ana Mountains, Puente Hills, and the Whittier fault: The final(?) grand theory of Orange County's tectonic geomorphic evolution" - Old Spaghetti Factory, San Marcos
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.
7/16/2025 Rachel Maxwell on a survey of the Mojave-Sonoran Desert Springs and their sources. "Is this spring connected to that Aquifer?"
6/18/2025 Development of the western Hollywood Basin and Cheviot Hills, and newly identified blind thrust in Santa Monica Bay - Dr. Miles Kenney
5/14/2025 Landslide Stabilization - Dr. Sebastian Lobo-Guerrero (Audio is very quiet first few minutes.)
4/16/2025 Constraining Natural and Anthropogenic Controls on Base of Freshwater and Underground Source of Drinking Water (USDW) In Central San Joaquin Valley - Emily Imperato
4/16/2025 Examination of Middle Cambrian hyoliths from the Manuels River Formation of Avalonian southeastern Newfoundland - Nicolas Oliver
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
Meetings are usually scheduled for the 3rd Wednesday evening of the month.
Meeting information on this website is normally updated the second week of the month.
If you are a current SDAG member and are not getting e-mail announcements,
make sure the SDAG secretary has your correct e-mail address.
If you have any information, announcements, ads or suggestions for an upcoming newsletter, please submit it to
2025 SDAG Secretary.
Any news regarding upcoming events that may be of interest to the Association or news of your business can be submitted.
The submittal deadline for the next SDAG newsletter is the last Friday of the month.
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