Physical Sciences and Mathematics Commons^™

Isotopic Signature Of Massive, Buried Ice In Eastern Taylor Valley, Antarctica: Implications For Its Origin, Christopher B. Gardner, Melisa A. Diaz, Devin F. Smith, Andrew G. Fountain, Joseph S. Levy, W. Berry Lyons

Geography Faculty Publications and Presentations

The coastal regions of the McMurdo Dry Valleys, Antarctica, contain deposits of the Ross Sea Drift, sedimentary material left from the Ross Sea ice sheet from the advance of the West Antarctic ice sheet during the Last Glacial Maximum. Much of this deposit is ice-cored, but data on the stable isotopic composition of water from this ice, which may contain a valuable climate archive, are sparse or incomplete. Widespread thermokarstic ground subsidence in this “coastal thaw zone” of the McMurdo Dry Valleys suggests that these potential records are rapidly being lost due to the melting of ground ice and permafrost. …

An Eolian Dust Origin For Clastic Fines Of Devono-Mississippian Mudrocks Of The Greater North American Midcontinent, Austin J. Mcglannan, Alicia Bonar, Lily Pfeifer, Sebastian Steinig, Paul Valdes, Steven Adams, David Duarte, Benmadi Milad, Andrew Cullen, Gerilyn S. Soreghan

School of Earth & Environment Faculty Scholarship

Upper Devonian and Lower–Middle Mississippian strata of the North American midcontinent are ubiquitously fine-grained and silt-rich, comprising both so-called shale as well as argillaceous limestone (or calcareous siltstone) that accumulated in the Laurentian epeiric sea. Although long recognized as recording marine deposition, the origin and transport of the fine-grained siliciclastic material in these units remains enigmatic because they do not connect to any proximal deltaic feeder systems. Here, we present new data on grain size, whole-rock geochemistry, mineralogy, and U-Pb detrital-zircon geochronology from units across Oklahoma; we then integrate these data with models of surface wind circulation, refined paleogeographic reconstructions, …

Surficial Geologic Map Of The Summit 7.5-Minute Quadrangle, Kentucky, Antonia E. Bottoms, Ann Hislop, Matthew A. Massey, Max Hammond Iii, Michelle Mchugh, Emily Morris

Report of Investigations--KGS

The Summit 7.5-minute quadrangle is located south of Louisville and west of Elizabethtown along the boundary between Hardin and Grayson Counties and within the Mississippian Plateau physiographic region (McDowell, 1986). Topography is characterized by the low relief Pennyroyal region that sits at elevations between 560 to 650 ft above sea level, the low relief Mammoth Cave plateau at elevations between 750 to 900 ft, and the steep Dripping Springs escarpment that separates the two plains. Moore (1964) mapped the bedrock geology of the quadrangle, which was later digitized by Conley (2002). Mississippian bedrock is exposed throughout the quadrangle and is …

Phase I Activities Of The Earth Mapping Resources Initiative (Earth Mri) In The Western Kentucky Fluorspar District, Georgina Lukoczki, Craig Dietsch, John B. Hickman, Emily Morris, Douglas C. Curl, Carrie Pulliam, Stephanie Vicroy, William M. Andrews Jr.

Report of Investigations--KGS

The Western Kentucky Fluorspar District (WKFD), which comprises the Kentucky portion of the Illinois–Kentucky Fluorspar District, is well known for the occurrence of strategically important critical mineral resources, such as fluorite (fluorspar) and rare earth elements (REEs). Due to technological advances, demand has increased for critical minerals used in cell phones, magnets in wind turbines, batteries for electric vehicles, smart weapons, and other devices and systems. The overall objective of the Earth Mapping Resources Initiative (Earth MRI) program, directed by the U.S. Geological Survey (USGS), is to gather information that will help better understand the distribution of critical minerals in …

Physical Controls On The Hydrology Of Perennially Ice-Covered Lakes, Taylor Valley, Antarctica (1996-2013), J. M. Cross, Andrew G. Fountain, M. J. Hoffman, M. K. Obryk

Geology Faculty Publications and Presentations

The McMurdo Dry Valleys, Antarctica, are a polar desert populated with numerous closed-watershed, perennially ice-covered lakes primarily fed by glacial melt. Lake levels have varied by as much as 8 m since 1972 and are currently rising after a decade of decreasing. Precipitation falls as snow, so lake hydrology is dominated by energy available to melt glacier ice and to sublimate lake ice. To understand the energy and hydrologic controls on lake level changes and to explain the variability between neighboring lakes, only a few kilometers apart, we model the hydrology for the three largest lakes in Taylor Valley. We …

Groundwater Modelling Of The Newman Area For Managed Aquifer Recharge Assessment, Wolfgang Schmid, Rodrigo Rojas, Michael J. Donn, Christopher Schelfhout Dr, Mathias Raiber, Olga Barron

Natural resources commissioned reports

This report contributes to the Transforming Agriculture in the Pilbara (TAP) initiative that has been developed to undertake the detailed studies in the Pilbara to bring suitable medium to large scale irrigation land to market for private investment. The research objective was to explore opportunities for irrigated agriculture north of Newman (Eastern Pilbara), deploying managed aquifer recharge (MAR) to secure water for irrigation. MAR source water identified was from mine dewatering surplus, generated from the large BHP Iron Ore operation in the Newman region. The objectives of this report were to:

• conceptualise the groundwater system and associated processes in the …

One Health In Action: Flea Control And Interpretative Education At Badlands National Park, David Eads, Lindsey Buehler, Anne Esbenshade, Jason Fly, Evan Miller, Holly Redmond, Emily Ritter, National Park Service, Sasha Wittmann, Paul Roghair, Eddie Childers

United States Geological Survey: Staff Publications

No abstract provided.

Inverting Passive Margin Stratigraphy For Marine Sediment Transport Dynamics Over Geologic Time, Charles Shobe, Jean Braun, Xiaoping Yuan, Benjamin Campforts, Boris Gailleton, Guillaume Baby, François Guillocheau, Cécile Robin

Faculty & Staff Scholarship

Passive margin stratigraphy contains time-integrated records of landscapes that have long since vanished. Quantitatively reading the stratigraphic record using coupled landscape evolution and stratigraphic forward models (SFMs) is a promising approach to extracting information about landscape history. However, there is no consensus about the optimal form of simple SFMs because there has been a lack of direct tests against observed stratigraphy in well-constrained test cases. Specifically, the extent to which SFM behaviour over geologic space and timescales should be governed by local (downslope sediment flux depends only on local slope) versus nonlocal (sediment flux depends on factors other than local …

Microbial Ecology Of A Shallow Alkaline Hydrothermal Vent: Strýtan Hydrothermal Field, Eyjafördur, Northern Iceland, Katrina I. Twing, L. M. Ward, Zachery K. Kane, Alexa Sanders, Roy Edward Price, H. Lizethe Pendleton, Donato Giovannelli, William J. Brazelton, Shawn E. Mcglynn

Geosciences: Faculty Publications

Strýtan Hydrothermal Field (SHF) is a submarine system located in Eyjafördur in northern Iceland composed of two main vents: Big Strýtan and Arnarnesstrýtan. The vents are shallow, ranging from 16 to 70 m water depth, and vent high pH (up to 10.2), moderate temperature (Tmax ∼70°C), anoxic, fresh fluids elevated in dissolved silica, with slightly elevated concentrations of hydrogen and methane. In contrast to other alkaline hydrothermal vents, SHF is unique because it is hosted in basalt and therefore the high pH is not created by serpentinization. While previous studies have assessed the geology and geochemistry of this site, the …

Do Pharmaceuticals In The Environment Pose A Risk To Wildlife?, Thomas G. Bean, Elizabeth A. Chadwick, Marta Herrero‐Villar, Rafael Mateo, Vinny Naidoo, Barnett A. Rattner

United States Geological Survey: Staff Publications

The vast majority of knowledge related to the question “To what extent do pharmaceuticals in the environment pose a risk to wildlife?” stems from the Asian vulture crisis (>99% decline of some species of Old World vultures on the Indian subcontinent related to the veterinary use of the nonsteroidal anti‐inflammatory drug [NSAID] diclofenac). The hazard of diclofenac and other NSAIDs (carprofen, flunixin, ketoprofen, nimesulide, phenylbutazone) to vultures and other avian species has since been demonstrated; indeed, only meloxicam and tolfenamic acid have been found to be vulture‐safe. Since diclofenac was approved for veterinary use in Spain and Italy in …

A 14,100 Cal B. P. Rocky Mountain Locust Cache From Winnemucca Lake, Pershing County, Nevada, Evan J. Pellegrini, Eugene M. Hattori, Larry Benson, John Southon, Hojun Song, Derek A. Woller

United States Geological Survey: Staff Publications

The remains of approximately 1000 (MNI) Rocky Mountain locusts (Melanoplus spretus) from an archaeological cache pit in Crypt Cave, Winnemucca (dry) Lake, Nevada, date to between 14,305–14,067 calendar years before present (95.4 % confidence; 12,238 ± 18 ¹⁴C yrs. B.P.). The age of this western Great Basin occupation along the shoreline of Lake Lahontan is consistent with occupation of several other Western North American terminal Pleistocene sites dating prior to 14,000 cal. B.P., including distinctive petroglyphs on the western shore of Winnemucca Lake dating as early as 14,800–13,200 cal. B.P.

Filling Critical Gaps In The Space-Time Record Of High Lava Plains And Co-Columbia River Basalt Group Rhyolite Volcanism, Vanessa Marie Swenton, Martin J. Streck, Daniel P. Miggins, William C. Mcintosh

Geology Faculty Publications and Presentations

Miocene rhyolitic volcanism of eastern Oregon, USA, can be divided into two main episodes. Mantle plume upwelling is thought to have generated Columbia River Basalt Group (CRBG) lavas and coeval >16.5−15 Ma silicic volcanism trending north−south from northeast Oregon to northern Nevada. Rhyolite volcanism of the 12−0 Ma High Lava Plains province has been ascribed to either buoyancy-driven westward plume spreading or to slab rollback and mantle convection spanning from southeast Oregon to Newberry Volcano to the west. The apparent ca. 15−12 Ma eruptive hiatus suggests that rhyolites of these provinces were a product of separate processes, yet this gap …

Wagin Townsite Borefield: Review Of Aquifer Performance, Rockwater

Natural resources commissioned reports

The Wagin Borefield was established by the Department of Agriculture and Food, Western Australia in 2000-2007 to control groundwater levels in the town that had risen to critical levels as a result of increased recharge and runoff following the clearing of native vegetation for urban development and agriculture. Similar investigations were conducted as part of the Rural Towns Program and Rural Towns-Liquid Assets projects in 41 other wheatbelt towns, but none, except perhaps from Merredin, have been as comprehensively implemented, operated and monitored as Wagin.

The Wagin Borefield comprises 8 production bores, of which only 3 have been operated. To …

Beyond Functional Diversity: The Importance Of Trophic Position To Understanding Functional Processes In Community Evolution, Roxanne M. W. Banker, Ashley A. Dineen, Melanie G. Sorman, Carrie L. Tyler, Peter D. Roopnarine

Geoscience Faculty Research

Ecosystem structure—that is the species present, the functions they represent, and how those functions interact—is an important determinant of community stability. This in turn a􀀀ects how ecosystems respond to natural and anthropogenic crises, and whether species or the ecological functions that they represent are able to persist. Here we use fossil data from museum collections, literature, and the Paleobiology Database to reconstruct trophic networks of Tethyan paleocommunities fromthe Anisian and Carnian (Triassic), Bathonian (Jurassic), and Aptian (Cretaceous) stages, and compare these to a previously reconstructed trophic network from a modern Jamaican reef community. We generated model food webs consistent with …

Comparative Behavioral Ecotoxicology Of Inland Silverside Larvae Exposed To Pyrethroids Across A Salinity Gradient, Sara J. Hutton, Samreen Siddiqui, Emily I. Pedersen, Christopher Y. Markgraf, Amelie Segarra, Michelle L. Hladik, Richard E. Connon, Susanne M. Brander

United States Geological Survey: Staff Publications

Pyrethroids, a class of commonly used insecticides, are frequently detected in aquatic environments, including estuaries. The influence that salinity has on organism physiology and the partitioning of hydrophobic chemicals, such as pyrethroids, has driven interest in how toxicity changes in saltwater compared to freshwater. Early life exposures in fish to pyrethroids cause toxicity at environmentally relevant concentrations, which can alter behavior. Behavior is a highly sensitive endpoint that influences overall organism fitness and can be used to detect toxicity of environmentally relevant concentrations of aquatic pollutants. Inland Silversides (Menidia beryllina), a commonly used euryhaline model fish species, were exposed …

Mountain Rivers Reveal The Earthquake Hazard Of Geologic Faults In Silicon Valley, Felipe Aron, Samuel A. Johnstone, Andreas Mavrommatis, Robert Sare, Frantz Maerten, John P. Loveless, Curtis W. Baden, George E. Hilley

Geosciences: Faculty Publications

The 1989, Mw = 6.9 Loma Prieta earthquake resulted in tens of lives lost and cost California almost 3% of its gross domestic product. Despite widespread damage, the earthquake did not clearly rupture the surface, challenging the identification and characterization of these hidden hazards. Here, we show that they can be illuminated by inverting fluvial topography for slip-and moment accrual-rates—fundamental components in earthquake hazard assessments—along relief-generating geologic faults. We applied this technique to thrust faults bounding the mountains along the western side of Silicon Valley in the San Francisco Bay Area, and discovered that these structures may be capable of …

Using Active Source Seismology To Image The Palos Verdes Fault Damage Zone As A Function Of Distance, Depth, And Geology, Travis Alongi, Emily E. Brodsky, Jared Kluesner, Daniel Brothers

United States Geological Survey: Staff Publications

Fault damage zones provide a window into the non-elastic processes of an earthquake. Geological and seismic tomography methods have been unable to measure damage zones at depth with sufficient spatial sampling to evaluate the relative influence of depth, distance, and lithological variations. Here, we identify and analyze the damage zone of the Palos Verdes Fault offshore southern California using two 3D seismic reflection datasets. We apply a novel algorithm to identify discontinuities attributed to faults and fractures in large seismic volumes and examine the spatial distribution of fault damage in sedimentary rock surrounding the Palos Verdes Fault. Our results show …

Coastal Wetland Area Change For Two Freshwater Diversions In The Mississippi River Delta, John R. White, Brady Couvillion, John W. Day

United States Geological Survey: Staff Publications

Coastal systems around the globe are being re-integrated with adjacent river systems to restore the natural hydrologic connection to riparian wetlands. The Mississippi River sediment diversions or river reconnections are one such tool to combat high rates of wetland loss in coastal Louisiana, USA by providing freshwater, sediment, and nutrients. There has been some disagreement in the published literature whether re-establishing river reconnection is slowing or contributing to coastal wetland loss. This issue is due to the difficulties in the application of remote sensing in low-relief environments where water level changes could indicate either land loss or simply temporary submergence. …

Preliminary Geochemical And Mineralogical Assessment Of The Beach Sand, Vieques, Puerto Rico, Nazrul I. Khandaker

Publications and Research

PRELIMINARY GEOCHEMICAL AND MINERALOGICAL ASSESSMENT OF THE BEACH SAND, VIEQUES, PUERTO RICO

ROBBINS, Kathy H., KHANDAKER, Nazrul, SINGH, Andrew, and MUNRO, Toralv, Geological Society of America Abstracts with Programs, Vol 54, No. 5, https://doi.org/10.1130/abs/2022AM-379886

ROBBINS, Kathy H., Bronx Early College Academy for Teaching and Learning, 250E 164 STREET, Bronx, NY 10456, KHANDAKER, Nazrul, Geology Discipline, York College of CUNY, 9420 Guy R Brewer Blvd, AC-2F09, Jamaica, NY 11451-0001, SINGH, Andrew, Earth and Physical Sciences, York College of CUNY, 9420 Guy R Brewer Blvd, AC-2F09, Jamaica, NY 11451-0001 and MUNRO, Toralv, 10911 164th St Apt 1, Jamaica, NY 11433-2921 …

Integrating Remote Digital Tools Into Post-Pandemic Geologic Fieldwork To Effectively Disseminate Content Delivery And Assist In Overall Understanding Of Various Geologic Phenomena: Summer 2022 Field Mapping Exercises, Nazrul I. Khandaker

Publications and Research

INTEGRATING REMOTE DIGITAL TOOLS INTO POST-PANDEMIC GEOLOGIC FIELDWORK TO EFFECTIVELY DISSEMINATE CONTENT DELIVERY AND ASSIST IN OVERALL UNDERSTANDING OF VARIOUS GEOLOGIC PHENOMENA: SUMMER 2022 FIELD MAPPING EXERCISES

SHAMI, Malek, BETHEL, Cherise, NUNEZ, Eddy, RAYHAN, Salam, KHANDAKER, Nazrul and CABAROY, Charren C.

Geological Society of America Abstracts with Programs. Vol 54, No. 5, https://doi.org/10.1130/abs/2022AM-379779

SHAMI, Malek¹, BETHEL, Cherise², NUNEZ, Eddy³, RAYHAN, Salam³, KHANDAKER, Nazrul² and CABAROY, Charren C.¹, (1)Geology Discipline, AC-2F09, York College of CUNY, 9420 Guy R. Brewer Blvd., Jamaica, NY 11451, (2)Geology Discipline, York College of CUNY, …

Assessing Student Performance And Interest From The Start Of The Covid-19 Pandemic To Present Using Engagement, Attendance, And Grades As Indicators, Nazrul I. Khandaker

Publications and Research

ASSESSING STUDENT PERFORMANCE AND INTEREST FROM THE START OF THE COVID-19 PANDEMIC TO PRESENT USING ENGAGEMENT, ATTENDANCE, AND GRADES AS INDICATORS

SINGH, Andrew, KHANDAKER, Nazrul, ZARINE, Ali, ROBBINS, Kathy H., JACKSON, Shirley and AHMED, Masud,

Geological Society of America Abstracts with Programs. Vol 54, No. 5, https://doi.org/10.1130/abs/2022AM-379409

SINGH, Andrew¹, KHANDAKER, Nazrul², ZARINE, Ali³, ROBBINS, Kathy H.⁴, JACKSON, Shirley³ and AHMED, Masud⁵, (1)Earth and Physical Sciences, York College of CUNY, 9420 Guy R Brewer Blvd, AC-2F09, Jamaica, NY 11451-0001, (2)Geology Discipline, York College of CUNY, 9420 Guy R Brewer …

Geochemical Analysis Of Recent Volcanic Ash Blanketing Barbados And Constraints On Magma Composition (V32e-0112), Nazrul I. Khandaker, Krishna Mahabir, Surendranauth Mahabir, Lloyd Kiefer, Juan C. Campo, Andrew M. Singh

Publications and Research

Preliminary field and geochemical investigations were conducted on ash samples from Barbados to chemically characterize and decipher magma chemistry associated with a recent volcanic event. A thick plume of volcanic ash from the La Soufriere Volcano in St Vincent, which erupted on April 9, 2021, caused lower visibility due to ash clouds which engulfed the region for some time. Three authors from the research team visited Barbados during the summer subsequent and completed a reconnaissance investigation on recent ashfall. St Vincent is a small volcanic island in the Eastern Caribbean and lies in the southern part of the Lesser Antilles …

Comparing Geosciences-Related Engagement Generated During And After The Use Of Multiple Pedagogical Approaches: Animated Videos, Youtube, Interactive Educational Games, Group Discussion And Powerpoint Presentations, Andrew M. Singh, Nazrul I. Khandaker, Ality Aghedo, Jasmin Budhan, Belal A. Sayeed, B'Jorn K. Forde, Krishna Mahabir

Publications and Research

The COVID-19 pandemic has increased educators’ reliance on online learning tools such as Blackboard Collaborate Ultra and Zoom meetings to deliver geoscience-related lessons in real-time. Assessments were conducted using introduction to geology, environmental geology, and oceanography - part of the City University of New York's (CUNY) newly implemented pathways curriculum. These general education courses belong to scientific world and life and physical sciences category and are intended for seamless transfer between CUNY campuses. Students, however, have the option to disengage from participation. Students are able to disable microphones and cameras, as well as rely entirely on text-chat if they choose. …

Evidence For The ~ 1.4 Ga Picuris Orogeny In The Central Colorado Front Range, Asha A. Mahatma, Yvette D. Kuiper, Christopher S. Holm-Denoma

United States Geological Survey: Staff Publications

We present the first evidence for sedimentation and new evidence for penetrative deformation and metamorphism in the central Colorado Front Range associated with the ~ 1.48–1.35 Ga Picuris orogeny. This orogeny has recently been recognized in New Mexico, Arizona and southern Colorado and may be part of a larger active accretionary margin that includes the ~ 1.51–1.46 Ga Pinware and Baraboo events, in eastern Canada and central US respectively, that preceded the amalgamation of the Rodinian supercontinent. We demonstrate that in addition to ~ 1.4 Ga reactivation of northeast-trending Paleoproterozoic shear zones, regional folding occurred in an area south of …

Level And Pattern Of Overstory Retention Shape The Abundance And Long-Term Dynamics Of Natural And Created Snags, Charles B. Halpern, Allison K. Rossman, Joan C. Hagar

United States Geological Survey: Staff Publications

Standing dead trees, or snags, serve myriad functions in natural forests, but are often scarce in forests managed for timber production. Variable retention (VR), the retention of live and dead trees through harvest, has been adopted globally as a less intensive form of regeneration harvest. In this study, we explore how two key elements of VR systems — level (amount) and spatial pattern of live-tree retention — affect the carryover and post-harvest dynamics of natural and artificially created snags. We present nearly two decades of data from the DEMO Study, a regional-scale experiment in VR harvests of Douglas-fir-dominated forests in …

Hydrogen Isotope Behavior During Rhyolite Glass Hydration Under Hydrothermal Conditions, Michael R. Hudak, Ilya N. Bindeman, James M. Watkins, Jacob B. Lowenstern

United States Geological Survey: Staff Publications

The diffusion of molecular water (H₂O_m) from the environment into volcanic glass can hydrate the glass up to several wt% at low temperature over long timescales. During this process, the water imprints its hydrogen isotope composition (δD_H2O) to the glass (δD_gl) offset by a glass-H₂O fractionation factor (ΔD_gl-H2O = δD_gl – δD_H2O) which is approximately -33‰ at Earth surface temperatures. Glasses hydrate much more rapidly at higher, sub-magmatic temperatures as they interact with H₂O during eruption, transport, and emplacement. To aid in the interpretation …

Magnetic Methods To Characterize The Emplacement Of The Nodule Point Intrusion (Marrowstone Island, Wa), Charlie Nuncio

Geology Graduate and Undergraduate Student Scholarship

The mafic intrusion of Nodule Point, Marrowstone Island, WA has sparse scientific literature to substantiate the local geologic history around its emplacement conditions. To fill this gap, rock magnetism and paleomagnetic methods have been applied to the intrusion and the sandstone of Scow Bay host rock. Samples taken from both lithologies were subject to thermal and alternating field demagnetization to assess paleomagnetic components. The Anisotropy of Magnetic Susceptibility (AMS) of samples was measured, and the maximum axis of susceptibility, K1, was used as an analog to hypothesize emplacement conditions. The host rock: the sandstone of Scow Bay, returned magnetization characteristics …

A Field Guide To Jezero Crater, Mars, Lee Adair

WWU Honors College Senior Projects

This project aims to blend art, creative writing, and scientific inquiry to explore the possibilities of geology research on our neighboring planet, Mars. This exploratory field guide combines journals, notes, and images to inform the reader of what they can expect to see on the Martian surface.

Soils Of The Central Nebraska Loess Hills And Central Loess Plains, Judith Turk, Rebecca Young, Nicolas A. Jelinsky, Amber D. Anderson, Ashlee Dere, Colby J. Moorberg, Rachel K. Owen

Conservation and Survey Division

Understanding soil systems that characterize a region is critical to natural resource management. However, the knowledge gained through intensive study of local soil systems, which takes place annually as part of collegiate soil judging contests, is often poorly preserved for future use. In this study, field descriptions and laboratory data for 16 soil profiles described for the 2019 Region 5 Soil Judging Contest were used to characterize the soil system of the Central Nebraska Loess Hills and Central Loess Plains. Three landscape components of this soil system were analyzed: the loess uplands and rainwater basins, the transitional zone, and bottomlands. …

Intact Polar Brgdgts In Arctic Lake Catchments: Implications For Lipid Sources And Paleoclimate Applications, Jonathan H. Raberg, Edgart Flores, Sarah E. Crump, Greg De Wet, Nadia Dildar, Gifford H. Miller, Áslaug Geirsdóttir, Julio Sepúlveda

Geosciences: Faculty Publications

Paleotemperature histories derived from lake sediment archives provide valuable context for modern and future climate changes. Branched glycerol dialkyl glycerol tetraether (brGDGT) lipids are a valuable tool in such pursuits due to their empirical correlation with temperature and near ubiquity in nature. However, the relative contributions of terrestrial and lacustrine sources of brGDGTs to lake sediments is site-dependent and difficult to constrain. Here, we explored the potential for intact brGDGTs—the complete lipids with polar head groups (HGs) still attached—to provide insight into the sources of brGDGTs on the landscape and their contributions to the sedimentary record in a set of …