Sarah Giles

About me

I am a geologist interested in understanding the co-evolution of environment, climate, tectonics, the ocean, and life.

My current Ph.D. research integrates field mapping, high-resolution sequence stratigraphy, petrography, isotope geochemistry, geochronology and structural restoration to evaluate the character, origin and timing of Neoproterozoic (1,000-541 Ma) incised valleys and geochemical anomalies in the Flinders Ranges, South Australia and the Nopah Range, California.

I am a current NSF Graduate Research Fellow and Lead Teaching Fellow at the Columbia Center for Teaching and Learning.

Education

Ph.D. in Geology at Columbia University (2018-2023)

M.A. and M. Phil in Geology at Columbia University (2020, 2021)

B.S. in Geology at Texas A&M University (2014-2018)

Research

Evaluation of the timing, origin and the potential global connections of mid-Ediacaran phenomena in South Australia and eastern California.

The origin of Ediacaran paleocanyons: Subaerial or submarine?

Incisions cut from a stratigraphic level within the Ediacaran Wonoka Fm. in South Australia (~ 1 km deep canyons) and the Johnnie Fm. in California (~120 m deep canyons). These paleocanyons are broadly coincident with the Shuram excursion and the emergence of the Ediacara fauna. The origin of both incisions remains debated, and could have implications for the unknown origins of the Shuram and Ediacara fauna. My field research uses GPS-enabled tablet-based geologic mapping at sub-meter resolution on drone imagery and detailed measurement of stratigraphic sections to evaluate the physical stratigraphic framework of the incision fill.

Ediacaran detrital zircon provenance in South Australia: Implications for the age of the Shuram excursion and Ediacaran paleogeographic reorganization

U-Pb detrital zircon geochronology on the lower Wilpena Group in South Australia is utilized to further calibrate the Ediacaran Period and provide constraints on the timing, duration, and origins of the Shuram excursion, as well as the timing of appearance of the Ediacaran soft-bodied fauna. K-Ar geochronology on glaucony grains in the Wonoka Fm. is additionally being explored.

Origin and character of the Shuram carbon isotope excursion

High-resolution physical stratigraphic mapping, thin-section petrography, and carbon and oxygen isotope geochemistry are utilized to evaluate the lithological characteristics of the rocks possessing the Shuram excursion in South Australia and California.

Potential fluid and structural alteration at the salt-sediment interface: Insights from Onion Creek Salt Diapir, Utah

Collaborative research utilizing calcite cement stratigraphy, geologic mapping, thin-section petrography, and geochemistry to evaluate controls on differential cementation and fluid flow in stratigraphy influenced by syndepositional structural deformation adjacent to salt. I co-supervised a team of 3 undergraduate students conducting collaborative research projects composed of both field and lab approaches that investigated this topic.

Students

I co-supervised 3 undergraduate students at the University of Texas at El Paso (UTEP) with UTEP Ph.D. student David Lankford-Bravo. We created an individual project for each student that involved a field and laboratory component, and worked with the students to write and receive research grants. Each student presented their research as a poster at the 2020 UTEP Colloquium and 2 of them recieved L. Austin Weeks AAPG Undergraduate Grants. I have also supervised 1 undergraduate student at Columbia University who was looking at the isotopic variation within a Precambrian oolite layer to determine if there was any paleowater depth dependence of the C & O isotopes. I will be co-supervising 2 new undergraduate students this Fall 2021 who will be evaluating trends in grain size distribution in modern fluvial and submarine channels using laser diffraction granulometry to determine the origins of ancient paleocanyons.

Projects:

Mia Ramirez, UTEP (2019-October 2020)-Mia utilizes geologic mapping, stratigraphic sections, 3D drone modeling, and structural restorations to evaluate how syndepositional extensional tectonism influenced the formation of the Johnnie Fm. (Rainstorm Member) valleys in the Nopah Ranges, CA.

Rachael Hill, UTEP (2019-May 2020)-Rachael used thin-section petrography and stratigraphic section measuring to evaluate the lithologic characteristics and variations in altered zones of Permian Cutler Fm. adjacent to the Onion Creek Salt Diapir, UT.

Hao Pham, UTEP (2019-June 2020)- Hao uses geologic mapping, 3D drone modeling, and structural restorations to evaluate how syn-depositional deformation influences the creation of isolated environments in a Permian fluvial depositional system adjacent to the Onion Creek Diapir, UT.

Juliet Tochterman, Columbia University (January 2020-July 2020)- Juliet micro-drilled oolite samples and analyzed their C & O isotopic values to determine if there was any Precambrian variation of isotopic values due to changes in paleowater depth.

Roy Lubash and Edinson Aquinaga, Columbia University (September 2021-May 2022)-These students will use laser diffraction granulometry to determine grain size distributions in modern and ancient valleys to evaluate their origins.

Sarah M. Giles