Their research is largely conducted on federal lands administered by the National Park Service, including Tule Springs Fossil Beds National Monument, Death Valley National Park, Joshua Tree National Park, Channel Islands National Park, and the Mojave National Preserve.

In White Sands National Park, Kathleen and Jeff have combined their region-wide experience with detailed stratigraphic analyses and cutting-edge dating techniques with their intimate understanding of past climate events to establish the age, geologic context, and paleoenvironmental setting of ancient human footprints recently discovered there – including the link to abrupt climate change that allowed the human and megafaunal footprints and trackways to be created and preserved. Archaeologists and researchers in allied fields have long sought to understand human colonization of North America. Questions remained about when and how people migrated, where they originated, and how their arrival affected the established fauna and landscape. evidence from excavated surfaces in White Sands National Park (New Mexico, United States), where multiple in situ human footprints are stratigraphically constrained and bracketed by seed layers that yield calibrated radiocarbon ages between ~23 and 21 thousand years ago. This timing coincided with a Northern Hemispheric abrupt warming event, Dansgaard-Oeschger event 2, which drew down lake levels and allowed humans and megafauna to walk on newly exposed surfaces, creating tracks that became preserved in the geologic record. These findings confirm the presence of humans in North America during the Last Glacial Maximum, adding evidence to the antiquity of human colonization of the Americas and providing a temporal range extension for the coexistence of early inhabitants and Pleistocene megafauna. Independent chronologic controls have confirmed the ages are correct and is the subject of our ongoing research. These results have upended traditional models regarding the peopling of the Americas and fundamentally change the very foundation of North American archaeology.

Quaternary Hydroclimate Records of Spring Ecosystems | U.S. Geological Survey

Fossilized Footprints – White Sands National Park (U.S. National Park Service)

Article Link: Evidence of humans in North America during the Last Glacial Maximum | Science

Abstract: 

Permian-to-Cretaceous igneous rocks of the Sierra Nevada Mountains were generated by almost 180 million years of oceanic plate subduction beneath the western edge of the North American continent. Tomographic imaging of the mantle beneath the southern Sierra Nevada reveals the presence of multiple oceanic slabs that implicates a complex history of Mesozoic continental collision, slab break-off, and crustal extension. This talk will explore the Permian-through-Jurassic tectonic evolution of southwestern Laurentia by integrating four different aspects of zircon geochemistry with field-based geology.

Abstract: 

The Santa Monica fault zone (SMFZ) extends across much of the densely populated City of Beverly Hills in southern California. State and local agencies require that active (Holocene) splays of the SMFZ be located and avoided (structural setbacks) prior to new construction. Accordingly, based on interpretation of ~80-100 m deep continuous cores, on arrays of cone-penetrometer tests (CPT), on limited geophysical data, on local street trenching, and on downhole logging of up to 15-m deep, overlapping bucket-auger holes, the ~300-m wide SMFZ is now documented to impact at least several famous, multi-million-dollar commercial structures in the “heart” of the Beverly Hills business district (Rodeo Drive). Subsurface sediment correlation is typically deduced from interpretation of 3-m centered continuous cores and cone penetrometer test (CPT) soundings. Sediment age is preferably based on multiple radiocarbon or OSL (optically stimulated luminescence) dates; but, in the common absence of such, soil-stratigraphic dating techniques are generally used.

Vertical fault displacement of a few cm may not be recognized owing to lack of slickensides on near-surface sediments and to 0.5-1.0 m-deep local channel incision. Where logistically feasible trenches may be excavated beneath existing structures in order to expose and measure possible fault offset and sediment age. The depth to the local Pleistocene/Holocene boundary varies, but – based mainly on radiocarbon and soil-stratigraphic dating – locally occurs between ~ 6-8 m, typically too deep for urban trench exposure. Increasingly, therefore, consultants drill 20-30, overlapping, 0.8 m diameter bucket-auger holes, which, when cleaned and logged, emulate trench walls. Such drilling is particularly expensive in cities and is typically done at night to reduce disruption to traffic and commercial activities. Coupled with difficulties of locating and avoiding unmarked utility lines and with required State and City technical reviews and permits, investigating the possible presence and impact of active faults on a single Beverly Hills commercial building may take over a year and exceed a million dollars.

Key words: urban active faults; investigation techniques; Beverly Hills, California

Abstract: 

The Sierra Nevada has played an important role in the history of paleoglaciology in the United States, and indeed globally.  The role of glaciation in shaping the range was discussed by J.D. Whitney, John Muir, and Joseph LeConte in the late 1860’s and the 1870’s.  Even at this early time, the evidence was abundant that the Sierra Nevada had been extensively glaciated in the not-too-distant geological past.

When Elliot Blackwelder in 1931 provided the first comprehensive description of the glacial history of the Sierra Nevada he recognized four glacial stages.  This was not because of widespread evidence for four advances, rather, it was because four stages were required by the prevailing paleoclimatic theory of his day.  In fact, while there is abundant evidence of the two most recent advances, that for Blackwelder’s two older stages is exceedingly fragmentary.  Blackwelder named the penultimate and the most recent glacial stages the ‘Tahoe’ and the ‘Tioga’, respectively.  Today, chronology provided mainly by cosmogenic nuclide accumulation dating, but supplemented by other methods, has demonstrated that the Tahoe is contemporaneous with the global glacial maximum of Marine Isotope Stage (MIS) 6 (~140 ka) and the Tioga with the maximum of MIS 2 (~20 ka).  Given that the severity of preceding glacial stages in the marine isotope record is very similar to these two stages, it seems highly likely that the Sierra Nevada over the past million years has undergone multiple glaciations of similar magnitude to the Tahoe and Tioga.  This is at least partially confirmed by geochemical evidence from a core in Owens Lake sediments that extends back to ~800 ka.  It shows multiple cycles of wet conditions very similar to the Tahoe and Tioga and dry conditions similar to the Holocene.  These cycles follow the same chronology as the Marine Isotope Stages.

The history of the deglaciation of the Sierra Nevada at the end of MIS 2 can be reconstructed in considerable detail, unlike previous advances and retreats for which the evidence has been destroyed by subsequent glacial erosion.  The evidence indicates that the glaciers reached a position close to that of the terminal moraine by 26 ka, well before the global Last Glacial Maximum at about 20 ka.  The terminal position was occupied from about 21 to 19 ka.  Between 19 and 16.7 ka the glaciers retreated far back in the range.  Between 16.7 and 16.2 ka they readvanced, eventually reaching about one-third of the glacial maximum extent.  At 16.2 ka they retreated very rapidly, deglaciating the Sierra Nevada, except perhaps for a few very small cirque glaciers.  There is no indication of subsequent glacial expansion until the diminutive Recess Peak advance between 14.0 and 12.5 ka. Whether this coincided with the quasi-global Younger Dryas event (12.9-11.6 ka) is uncertain.

During the early Holocene, even the tiny cirque glaciers apparently disappeared.  These re-formed at about 3 ka and advanced until the termination of the Little Ice Age at the end of the Nineteenth Century.  Today they are rapidly disappearing as Global Warming renders the Sierra Nevada unsuitable for glaciers.

In the end, the 74 people in attendance heard a presentation on the tephrochronology of the Monterey and Modelo Formations. Many of the samples were collected during grading operations here in Orange County. Hopefully, not too many people were disappointed and we will try and get Sue Hough at a future meeting to tell us about the Northridge earthquake.

McMichael, Ryan (CSUF – Undergraduate)

“Unveiling the Secrets of Marine Terrace Rings: A Window into Paleoenvironmental Change and Ecological Shifts”

Munoz, Jonathan (CSUF – Undergraduate)

“Uncovering Hidden Influence: Unconventional Non-Demographic Variables Shape Success and Close Educational Gaps in Introductory Geology”

Onderdonk, Nate (CSULB – Professor)

“Paleomagnetic directions and Argon dating of Miocene rocks show unusually rapid vertical-axis rotation on Santa Catalina Island, offshore southern California“

Ortega, Sonny (CSUF – Undergraduate)

“Assessing the role of wood fragments in the formation of calcite concretions of the Late Cretaceous Holz Shale, Santa Ana Mountains“

Ruiz, Roberto (CSUF – Undergraduate)

“Rancho Mission Viejo Riding Park Recharge System“

Scandore, Alex (CSULB – Undergraduate)

“Alteration and hydrothermal fluid provenance in the Lima Segment of the Peruvian Coastal Batholith”

Walters, Polito (CSULB)

“Hydrothermal Alteration Related to the Brittle-Ductile Transition at the Sierra Crest Shear Zone, Eastern Sierra Nevada, California”

Wilkins, Shaun (Langan – Professional)

“500-foot Slip or Slide”

Woodard, Brennen (CSUF – Undergraduate)

“The Requirements for Constructing a Favorable Recharge Well in San Juan Capistrano, California”

Abstract:

Cone Penetrometer Test (CPT) soundings are an often-used method to characterize subsurface soil behavior properties mostly in soft material conditions. The method has many geotechnical applications, some of which include liquefaction analysis, mapping of alluvial deposits and fill, evaluation of soil density improvement and determination of seismic S- and P-wave velocities. When a series of CPTs is advanced, the subsurface stratigraphy can be profiled. This was recognized early on and soon CPTs were engaged to identify stratigraphic disruptions indicative of faulting. This method is now widely used in the coastal province of Southern California, mostly in upper Quaternary materials. Oftentimes, only several feet or less of vertical differential across unit horizons or thickness variations in strata are used to identify potential faulting. This means it is imperative that depth recording of CPTs are as accurate as possible.

Several factors can cause errors in depth readings, leading to erroneous interpretations of faulting. These factors will be discussed in this presentation as well as a quality control procedure to track actual depths and thus mitigate errors. In addition, several examples will be presented where inaccurate depth readings resulted in misinterpretation of faulting. Finally, both the advantages and limitations of the CPT method will be discussed.

Abstract:

The advancement of fiber optic distributed sensing over the past two decades has enabled the measurement of subsurface hydraulics and geomechanics at unprecedented temporal and spatial detail. Fiber optic distributed sensing systems operate by firing laser light down a fiber optic cable and using backscattered photons to measure temperature, vibration, or strain. Kilometers of measurements can be made at scales as small as a centimeter and at sampling intervals of less than a millisecond.

We will look at how this technology has improved our understanding of subsurface flow related to diverse applications such as stream discharge, managed aquifer recharge, remediation of contaminated sites, aquifer testing, fracture hydromechanics, and energy resources. As these instruments become more reliable, accurate, and economical, opportunities for revolutionary observations of groundwater systems will continue to expand in the coming decades.

Abstract:

From late December 2022 until late March 2023, sixteen atmospheric river (AR) events impacted California, resulting in year-to-date precipitation accumulations varying from more than 200 to 350% above average across a wide swath of the state. Historic flooding and multi-modal landslide activity occurred statewide, damaging transportation infrastructure, homes, property, and threatening life-safety and economic welfare. A state of emergency was declared by the Governor of California as well as by the President of the United States. The California Governor’s Office of Emergency Services (CalOES) mission tasked the California Geological Survey (CGS) to provide situational awareness of statewide landslide hazards, which CGS accomplished in partnership with the United States Geological Survey (USGS) as well as numerous state, county, and local agencies.

CGS leveraged its Reported Landslides Database (RLD) mapping tools for desktop and field surveying to rapidly identify areas of observed landslide impacts, which included activation of a Landslides Triage Team (LTT). For several months the LTT gathered data from multiple sources including, but not limited to, photos and timing information from crowd-sourced reporting (e.g., Twitter, Facebook), local news media sources, state agency reporting, California Highway Patrol data, and review of firsthand reports.

The LTT identified more than 1000 AR-induced landslide events, necessitating the development of a GIS dashboard for efficient data organization. The GIS dashboard informed leadership of hardest hit areas and provided real-time support for community recovery accomplished by deployment of CalOES-requested CGS field teams at fourteen locations statewide. These mission tasks involved multi-partner agency collaboration and implementation of innovative field mapping, hazard surveying, and data collection methods. Here we highlight CGS mission task methods and results and discuss the successful public awareness campaign CGS developed to communicate the evolving nature of landslide hazards statewide. This public communication included an emergency response website, consistent Twitter communications to provide daily updates of a statewide landslide event density map, and a statewide deep-seated landslide “barometer” map.

Abstract:

Southern California is not new to unusual weather patterns and this past year did not disappoint. Between getting an abundance of rainfall in the winter season and a surprising tropical storm in August, how much rain did we receive and capture this past year? Are we ready for what’s ahead? Hear about what the Orange County Water District is doing to maximize stormwater capture and groundwater recharge opportunities which increase drinking water supplies for Orange County.