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Erin Todd, Ph.D.

Igneous petrology and isotope geochemistry, with particular emphasis on the origin and evolution of melts associated with subduction zones.

Professional Experience

  • 2012 - Present     Research Geologist, USGS Alaska Science Center, Anchorage, Alaska

  • 2011 - 2012           Postdoctoral Research Associate, WWU - University of Münster

  • 2005 - 2011          Research and Teaching Assistant, University of California, Santa Cruz, CA

Education and Certifications

  • Ph.D.      2011    University of California, Santa Cruz, CA       Earth Sciences

  • M.S.       2005    Northern Arizona University, Flagstaff, AZ    Geology

  • B.S.        1999    University of Florida, Gainesville, FL            Geology

Affiliations and Memberships*

  • American Geophysical Union

  • Geochemical Society

  • Geological Society of America

  • InterRIDGE

Science and Products

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Scientists wait for a helicopter pickup at a geologic mapping and sampling station high in the Neacola Mountains, Alaska

Metallogeny and Tectonics of the Lake Clark and Neacola Mountains Region, South-central Alaska

Alaska hosts a well-documented belt of ore deposits that lies roughly parallel to the Alaska Range, beginning at the Alaska Peninsula in the southwest, continuing up through the Fairbanks Mining District in the north, and curving back into the Tintina Gold Belt on its eastern end. Known mineral prospects and occurrences include porphyry copper, intrusion-related gold, volcanogenic massive sulfides...
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Mineral Resources Program, Alaska Science Center
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Metallogeny and Tectonics of the Lake Clark and Neacola Mountains Region, South-central Alaska

Alaska hosts a well-documented belt of ore deposits that lies roughly parallel to the Alaska Range, beginning at the Alaska Peninsula in the southwest, continuing up through the Fairbanks Mining District in the north, and curving back into the Tintina Gold Belt on its eastern end. Known mineral prospects and occurrences include porphyry copper, intrusion-related gold, volcanogenic massive sulfides...
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Uranium-Lead Ages, Hafnium Isotope Ratios, and Trace Element Concentrations by Laser-Ablation Split Stream (LASS) Analysis of Igneous Zircons from the Darby Mountains Area, Seward Peninsula, Alaska

This data set contains uranium-lead (U-Pb) isotopic data and ages, hafnium (Hf) isotope data, and trace element concentrations of zircon from igneous rocks collected from the Darby Mountains area of the Seward Peninsula, Alaska. The sample suite was collected as part of geological mapping and supporting geochemical and geochronological analysis conducted in 2017. The data tables accompanying this
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Alaska Science Center

Whole Rock Major and Trace Element Chemistry for Igneous and Metamorphic Rocks from the Yukon-Tanana Upland, Alaska

This data set consists of one table containing whole-rock geochemistry data for 753 igneous and metamorphic rocks from the Yukon-Tanana upland of eastern interior Alaska, collected between 2013 and 2019. All materials were analyzed by ALS Global, between 2014 and 2020, by a range of different techniques, so multiple unique entries for a given element relate to different analytical methods or prepa
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Alaska Science Center

Whole Rock Major and Trace Element Chemistry for Igneous Rocks from Tyonek, Lime Hills, Talkeetna, McGrath, and Lake Clark Quadrangles, Western Alaska Range, Alaska

This data release contains whole rock major and trace element data for 69 igneous rock samples collected from the Western Alaska Range between 2011 and 2012. The Series field relates to chronological units discussed in Jones et al. (2021, Geosphere) and Todd et al. (2022 IN PREP). Descriptions are from original collector notebooks and are provided here for informational purposes only.
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Alaska Science Center

Whole Rock Major and Trace Element Chemistry for Igneous and Sedimentary Rocks from the Western Alaska Range, Alaska

This data release contains whole rock major and trace element data for 399 igneous and sedimentary rock samples collected from the Western Alaska Range between 1968 and 2014 and funded by the Mineral Resources Program of the U.S. Geological Survey. All materials were analyzed by ALS Global, between 2014 and 2018, by a range of different techniques, so multiple unique entries for a given element re
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Alaska Science Center

U-Pb Isotopic Data and Ages of Zircon and Titanite from Rocks from the Western Alaska Range, Northern Aleutian Range, Taylor Mountains, and Tikchik Mountains Regions, Alaska

This data set contains U-Pb isotopic data and ages of zircon and titanite from igneous and metamorphic rocks collected from the western Alaska and northern Aleutian Range of south-central Alaska. The data sets also contain U-Pb isotopic data and ages of detrital zircon from sedimentary and metasedimentary rocks collected in the same region but also from the Taylor and Wood River Mountains of south
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Alaska Science Center
Geologist Jamey Jones studying and preparing to collect samples of igneous rocks in Lake Clark National Park
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Geologist collects multiple samples of rocks exposed in a glacial stream valley near Lake Clark
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Geologist stands on granite dike intruding darker granodiorite, with a helicopter in the background
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Geologists collect samples and take notes near Lake Clark
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Geologists make observations above glacial valley
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Molybdenite mineral coating on a fractured surface in Tertiary granite north of Lake Clark
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Geologists discuss big picture geology of Lake Clark National Park
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Geologist collects sample with helicopter in background, Lake Clark
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USGS researcher Jonathan Caine measures vein orientation at an outcrop of late Cretaceous pluton in Lake Clark National Park.
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Cross-cutting relationships of at least 4 different phases of rock and high-temperature silicate fluids
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Breaking up is hard to do: Magmatism during oceanic arc breakup, subduction reversal, and cessation

The formerly continuous Vitiaz Arc broke into its Vanuatu and Fijian portions during a reversal of subduction polarity in the Miocene. Basaltic volcanism in Fiji that accompanied the breakup ranged from shoshonitic to low-K and boninitic with increasing distance from the broken edge of the arc that, presumably, marks the broken edge of the slab. The Sr-Pb-Nd isotope ratios of the slab-derived comp
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Ecosystems, Alaska Science Center

Chemical geodynamics insights from a machine learning approach

The radiogenic isotope heterogeneity of oceanic basalts is often assessed using 2D isotope ratio diagrams. But because the underlying data are at least six dimensional (87Sr/86Sr, 143Nd/144Nd, 176Hf/177Hf, and 208,207,206Pb/204Pb), it is important to examine isotopic affinities in multi-dimensional data space. Here, we apply t-distributed stochastic neighbor embedding (t-SNE), a multi-variate stat
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Ecosystems, Alaska Science Center

Juvenile continental crust evolution in a modern oceanic arc setting: Petrogenesis of Cenozoic felsic plutons in Fiji, SW Pacific

Viti Levu, Fiji, provides one of the best exposed Phanerozoic analogues for the formation of juvenile continental crust in an intra-oceanic setting. Tonalites and trondhjemites are present in several large (75–150 km2) adjacent, mid-Cenozoic plutons. We report major and trace element data including rare earth element (REE) and high-precision high field strength element (HFSE) compositions, new Hf-
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Alaska Science Center

Sr, Nd, Hf and Pb isotope geochemistry of Early Miocene shoshonitic lavas from the South Fiji Basin: Note

We present new Sr, Nd, Hf and Pb isotope data for Early Miocene shoshonitic and high-K lavas dredged from seamounts in the South Fiji Basin, southwest Pacific Ocean. Our analyses provide a useful reference dataset for this distinctive compositional suite. The shoshonitic lavas formed in an intra-oceanic back-arc basin setting and are broadly coeval with nearby arc and back-arc basin lavas. Further
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Alaska Science Center

Cretaceous to Oligocene magmatic and tectonic evolution of the western Alaska Range: insights from U-Pb and 40Ar/39Ar geochronology

New U-Pb and 40Ar/39Ar ages integrated with geologic mapping and observations across the western Alaska Range constrain the distribution and tectonic setting of Cretaceous to Oligocene magmatism along an evolving accretionary plate margin in south-central Alaska. These rocks were emplaced across basement domains that include Neoproterozoic to Jurassic carbonate and siliciclastic strata of the Fare
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Alaska Science Center, Geology, Geophysics, and Geochemistry Science Center

Basalt geochemistry and mantle flow during early backarc basin evolution: Havre Trough and Kermadec Arc, southwest Pacific

The Havre Trough (HT) backarc basin in the southwest Pacific is in the rifting stage of development. We distinguish five types of basalt there based on their amount and kind of slab component: backarc basalts (BAB) with little or no slab component, modified BAB with slight amounts, reararc (RA) with more, remnants of the preexisting arc (Colville Ridge horsts), and arc front volcanoes within the H
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Alaska Science Center

GIS-Based Identification of Areas with Mineral Resource Potential for Six Selected Deposit Groups, Bureau of Land Management Central Yukon Planning Area, Alaska

This study, covering the Bureau of Land Management (BLM) Central Yukon Planning Area (CYPA), Alaska, was prepared to aid BLM mineral resource management planning. Estimated mineral resource potential and certainty are mapped for six selected mineral deposit groups: (1) rare earth element (REE) deposits associated with peralkaline to carbonatitic intrusive igneous rocks, (2) placer and paleoplacer
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Groundwater and Streamflow Information Program, Mineral Resources Program, Alaska Science Center, Geology, Minerals, Energy, and Geophysics Science Center, Geology, Geophysics, and Geochemistry Science Center

Links between tectonics, magmatism, and mineralization in the formation of Late Cretaceous porphyry systems in the Yukon-Tanana upland, eastern Alaska, USA

Cretaceous-Paleocene porphyry Cu(±Mo±Au) occurrences are scattered throughout the Yukon-Tanana upland in eastern Alaska. Known occurrences in eastern Alaska are poorly characterized, despite a resurgence in exploration. Porphyry deposits in the upland are emplaced into structurally complex metamorphic rocks representing a variety of tectonic environments, resulting in diverse alteration and minera
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Alaska Science Center

Effects of simple acid leaching of crushed and powdered geological materials on high-precision Pb isotope analyses

We present new results of simple acid leaching experiments on the Pb isotope composition of USGS standard reference material powders and on ocean island basalt whole rock splits and powders. Rock samples were leached with cold 6 N HCl in an ultrasonic bath, then on a hot plate, and washed with ultrapure H2O before sample digestion in HF‐HNO3 and chromatographic purification of Pb. Lead isotope ana
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Alaska Science Center

U-Pb and Lu-Hf isotope, age, and trace-element data from zircons at four sites in the western Alaska Range and Talkeetna Mountains, Alaska

This Division of Geological & Geophysical Surveys (DGGS) Raw Data File presents U-Pb geochronology and Lu-Hf isotopic compositions, age-dating results, and additional trace-elemental composition of zircons from four granitoids sampled during investigations by DGGS geologists in the western Alaska Range and the Talkeetna Mountains. The purpose of the Lu-Hf and U-Pb isotopic study was to better unde
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Alaska Science Center

Copahue volcano and its regional magmatic setting

Copahue volcano (Province of Neuquen, Argentina) has produced lavas and strombolian deposits over several 100,000s of years, building a rounded volcano with a 3 km elevation. The products are mainly basaltic andesites, with the 2000–2012 eruptive products the most mafic. The geochemistry of Copahue products is compared with those of the main Andes arc (Llaima, Callaqui, Tolhuaca), the older Caviah
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Groundwater and Streamflow Information Program, Mineral Resources Program, Alaska Science Center

Science and Products

*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government