About

Emily H. G. Cooperdock is an Assistant Professor in the Department of Earth, Environmental & Planetary Sciences at Brown University. Her research interests include geochemistry, tectonics, volcanology, and petrology. She focuses on understanding the role that exhumation and fluid-rock interactions have on tectonic and geochemical processes. Cooperdock uses (U-Th)/He thermochronology, geochemistry, and petrology to date minerals formed during fluid alteration, investigate geochemical fingerprints of fluid-rock interactions and volatile cycling at different tectonic settings, and constrain the thermal history of convergent and divergent plate margins. Additionally, she is interested in the history of diversity in the geosciences and efforts to make the discipline more inclusive.

Research topics

• Political Science
• Biology
• Virology
• Psychology
• Public relations

Selected publications

• Nitrogen Sources and Mineral Hosts within Shallow Sedimentary Mélange Matrix: Insights from San Simeon, California

  Abstracts with programs - Geological Society of America · 2025-01-01

  article
  PublisherDOI

• Plutonic Piercing Points as Recorders of Continental Transform Fault Evolution: Chronologic Insights From the Transpressive Southern San Andreas Fault

  Tectonics · 2025-04-01

  article

  Abstract The San Andreas Fault (SAF) zone is a prototypical continental transform fault system used to understand the rates and timing of plate‐boundary‐scale deformation. Extensive studies of the SAF document internal complexities, including how transpressive uplift occurs and varies spatially in strike‐slip systems. We utilize geochronology and low‐temperature thermochronology to re‐evaluate a plutonic piercing point and to identify heterogeneities in exhumation along the SAF restraining bend, known as the “Big Bend.” The Triassic K‐feldspar megaporphyritic monzogranite piercing point at Liebre Mountain and Mill Creek represents ∼160 km of right‐lateral fault motion. Here we present new zircon U‐Pb, bulk rock geochemistry, apatite and zircon (U‐Th)/He, and apatite fission track chronometry on a high‐resolution fault‐perpendicular sample transect from 0.25 to 4 km away from the SAF. Our results, coupled with inverse thermal history modeling, confirm that the Liebre Mountain and Mill Creek bodies broadly share a thermal history until the initiation of SAF‐related separation at ∼5 Ma. Age relationships along fault‐perpendicular transects reveal asymmetrical uplift recorded in the lowest temperature chronometers (<120°C) closest to the fault. Our results show that Mill Creek has undergone vertical exhumation in the last 5 million years as evidenced by young ∼2 Ma apatite (U‐Th)/He ages. We propose that recent differential uplift along the Big Bend could be tied to localized subsurface fault geometry and dip angle. We confirm that the Triassic megaporphyritic monzogranite is a robust piercing point that can be used in holistic reconstructions of the SAF and provides insight into mountain‐building kinematics in strike‐slip systems.

  PublisherDOI

• Mechanisms of Mass Transfer in Sediment‐Rich Mélanges in Modern Subduction Zones

  Journal of Geophysical Research Solid Earth · 2025-10-01 · 1 citations

  articleSenior author

  Abstract Sediment‐rich mélange diapirs have been suggested to transport key chemical slab signatures and volatiles to arc magma sources. Here, we assess the phase equilibria, buoyancy and implications for chemical geodynamics of a previously unexplored hydrous shaly‐rich mélange (5–10 wt.% H 2 O) with minor ultramafic component, from deep forearc to subarc depths (2–3 GPa and 700–1,150°C). The solidus lies between <645°C and 700°C and upon partial melting, produce dacitic to rhyolitic melts coexisting with a low‐density pyroxenite enriched in mica, amphibole, quartz, garnet and accessory minerals. Our analysis shows that instabilities are likely in warm, slow‐subducting and thinner channels with low viscosities compared to cold and fast subducting slabs where diapirism is likely limited, as they require extremely large channel thicknesses. Diapirism can occur in tectonic slabs with heat sources, such as nearby slab tears or plumes. However, those mélanges lose buoyancy upon thermal equilibration at temperatures above 850°C. While smaller diapirs may densify and stagnate near the channel, larger diapirs may maintain buoyancy, allowing them to remelt beneath the overriding lithosphere. Aqueous fluids and low‐degree melts prevail near the channel, transferring high Large Ion Lithophile Element (LILE)/High‐Field Strength Element (HFSE) ratios to arc magma sources, which resemble those found in arc lavas. High degree melting of mantle‐wedge diapirs may explain arc lava diversity but not their ubiquitous high LILE/HFSE signatures. Overall, diapirism is highly conditional and likely originate in hot slabs. Thus, aqueous fluids and partial melts are the dominant mass‐transfer agents of slab signatures to arc magma sources.

  PublisherDOI

• Uranium Addition and Loss in Serpentinites: The Potential Role of Iron Oxides

  Geochemistry Geophysics Geosystems · 2025-09-01

  articleOpen access1st author

  Abstract Fluid‐mobile uranium serves as a tracer for water‐rock alteration in serpentinized mantle rocks, which constitute an important uranium reservoir. However, the mechanism for uranium addition, where uranium is hosted, and the stability of the uranium enriched material during subduction is not settled. We use geochemistry data from marine (mid‐ocean ridge and fracture zone, fore‐arc, fore‐arc muds) and subaerially exposed (subducted, obducted, orogenic) serpentinites to show that uranium enrichment varies systematically with tectonic setting and depth from the seafloor. Only the upper ∼100 m of drilled and dredged serpentinites from marine settings contain ≥0.1 μg/g uranium enrichment, which does not correlate with the degree of serpentinization. Other settings (deeper marine samples, subducted, obducted and/or orogenic serpentinites) do not show the same degree of uranium enrichment, suggesting that uranium was lost or never gained. We use these data to argue that uranium addition requires oxidizing—bearing fluids and that uranium enrichment can be used as an indicator of these conditions. To understand where uranium is hosted, we show that uranium is enriched in samples with bulk rock Fe 3+ /Fe tot ≥ 0.6 and appears to be buffered at a maximum uranium concentration of ∼1 μg/g. We explore potential mineral hosts for uranium in highly enriched serpentinites and propose that Fe‐(oxyhydr)oxides (e.g., hematite, goethite) formed during weathering and/or carbonation could be under‐appreciated hosts for uranium in serpentinized systems. We use these results to explore implications for uranium cycling and uranium isotope fractionation during subduction.

  PublisherOA PDFDOI

• LONG TERM SAN ANDREAS FAULT HISTORY RE-EXAMINED THROUGH A MULTICHRONOMETER STUDY OF A PIERCING POINT

  Abstracts with programs - Geological Society of America · 2024-01-01

  article
  PublisherDOI

• Constraining Halogen Budgets in Continental Arcs at the Whole-Rock Scale

  2024-01-01

  articleOpen access
  PublisherOA PDFDOI

• ASSESSING INCLUSIONS AND Li CONCENTRATIONS IN MAGNETITE FOR COSMOGENIC ³He DATING

  Abstracts with programs - Geological Society of America · 2024-01-01

  article
  PublisherDOI

• Corrigendum to “A continental forearc serpentinite diapir with deep origins: Elemental signatures of slab-derived fluids and a mantle wedge protolith at New Idria, California” [Lithos, 398–399 (2021) 106252]

  Lithos · 2024-04-15

  erratum
  PublisherDOI

• Author Correction: No progress on diversity in 40 years

  Nature Geoscience · 2024-12-18

  articleOpen accessSenior authorCorresponding
  PublisherOA PDFDOI

• The Journey of Sediment-Rich Mélanges in Subduction Zones

  2024-12-16

  preprintOpen accessSenior author

  Sediment-rich mélange diapirs have been suggested to transport key chemical slab signatures and volatiles to arc magma sources. Here, we assess the phase equilibria, buoyancy and implications for chemical geodynamics of a previously unexplored hydrous shaly-rich mélange (5-10 wt.% H2O) with minor ultramafic component (9:1 ratio) from deep forearc to subarc depths (2-3 GPa and 700-1150°C). Their solidi lie between <645 to ~700°C and upon partial melting, produce dacitic to rhyolitic melts (water-free basis) in coexistence with abundant biotite, pargasitic-amphibole, and quartz (low dense minerals), garnet, and enstatite (rutile/Ti-magnetite ± apatite) that favors the onset of diapirs in thinner mélange channels (<100m) with lower mélange and mantle viscosities in all slab geotherms. At >850°C the low dense mineral abundance decreases, and the mélange loses buoyancy, requiring thicker mélange channels (>100-800m) with higher mélange and mantle viscosities. Thinner and thicker mélanges form smaller (<1 km radius) and larger diapirs (>1 km radius), respectively. While smaller are more susceptible to mineralogical equilibration, lose buoyancy and stall, larger diapirs may sustain buoyancy and relaminate under the arc crust. High LILE/HFSE signatures in most arc lavas may be explained by aqueous fluids and low degree mélange partial melting (<850°C) within the channel or a diapir close to the channel where rutile/apatite/Ti-Fe-oxides minerals are stable, and the presence of garnet impart high LILE/HREE. Although high degree partial melts due to diapirism or slab tears explain dacitic to rhyolitic arc lavas, they would not fractionate HFSEs from LILEs to explain the high HFSE/LILE arc lava signature.

  PublisherOA PDFDOI

Recent grants

• Collaborative Research: Evaluating The Exhumation History of the Aleutians with Zircon And Apatite Thermochronology

  NSF · $373k · 2020–2023

Frequent coauthors

• Florian Hofmann

  32 shared

• Daniel F. Stöckli

  The University of Texas at Austin

  15 shared

• Aaron J. Celestian

  10 shared

• Ananya Mallik

  9 shared

• Anahi Carrera

  University of Southern California

  9 shared

• A. Joshua West

  University of Southern California

  8 shared

• Richard A. Ketcham

  The University of Texas at Austin

  7 shared

• Aya Takase

  7 shared

Labs

• Department of Earth, Environmental & Planetary Sciences, Brown UniversityPI

Education

• PhD, Geological Sciences

  University of Texas at Austin

  2017

• BA, Earth and Environmental Sciences

  Columbia University

  2011