Alan Rooney

Bio

I am interested in understanding the interactions between tectonics, climatic processes and geochemical cycles on a range of time scales. I use radiogenic isotope geochemistry, in particular the rhenium-osmium (Re-Os) geochronometer, Sr and Nd isotopes combined with field-based mapping, sedimentology, stratigraphy and mineralogy to interrogate the rock record of critical transitions in Earth history.

My near term research interests are centered on three main areas: 1) refining Earth history records, especially Proterozoic tectonic reorganizations and eukaryotic diversification, 2) combining multiple geochemical proxies to provide better constraints on ice sheet dynamics over the last 5 million years, and 3) employing radiogenic isotopes as tracers of crustal-mantle processes.

Rooney Geochronology Lab

Welcome to the Rooney Geochronology and Geochemistry Group! We are a part of the Yale Metal Geochemistry Center. Our group utilizes the Re-Os geochronometer as well as Sr and Nd isotopes in conjunction with mineralogy, field mapping, sedimentology and stratigraphy to investigate climatic, biologic and tectonic transitions in earth’s history. Current projects involve resolving spatial-temporal Quaternary ice sheet dynamics and understanding and refining the timing of biological innovation, extinction and ice ages in the Neoproterozoic and Ordovician.

Investigating radiogenic isotopes as paleoweathering tracers - an experimental approach to understanding geochemical records from the sedimentary rock archive.

Radiogenic isotopes (e.g. Sr, Nd and Os) are providing critical new datasets that can be used to interrogate changes in tectonics and global climate as recorded in sedimentary archies that document episodes of upheaval throught Earth History. However, our understanding of how geochemical processes operate at mid-ocean ridges with respect to fluxes of these elements is currently lacking. My group is interested in combining eperimental approaches, petrology and mineralogy and isotope geochemistry to understand the factors that control the concentration and isotopic composition of these elements in seawater and deconvolve their paths into the sedimentary rock record. Of particular interest are experimental approaches to better understand seafloor weathering of mafic and ultramafic units. This research will establish how these elements behave in modern ocenas and provide effective contraints for proper interpretation of how the sedimentary rock record reflects changes in climate and habitability through Earth’s history.

Current projects involve resolving spatial-temporal Quaternary ice sheet dynamics and understanding and refinig the timing of biological innovation, extinction and ice ages in the Neoproterozic and Ordovician. Short descriptions of ongoing projects can be found here.

Biological Innovations and the Breakup of Rodina - Tonian of Svalbard

The breakup of Rodinia during the late Neoproterozoic was responsible for changes in primary productivity due to the formation of isolated basins with variable redox environments. Many biosphere firsts occurred during the Tonian, including the advent of biomineralization, development of exoskeletons, rise of eukaryotic predation and the appearnace of authigenic phosphate burial. Neoproterozoic sections are exceptionally well-preserved in Svalbard, due to recent deglaciation, and provide unparalleled opportunities to investigate the biotic and geochemical histories of this time. Current research goals in this time period center on providing radiometric ages to resolve questions surrounding the tempo of eukaryotic evolution. This project is part of a collaboration with researchers at Dartmouth College and Oxford University.

Mid-Pleistocene Transition

The Mid-Pleistoncene Transition (MPT) was characterized by a shift from 41-ky to 100-ky variability in glacial cycles, without change or obital forcing parameters. While the specific drivers of this transition remain elusive, it has been suggested that the MPT occurred as either the result of a shift in internal ice sheet dynamics, which pushed ice sheets towards a longer and larger stable state, or an increase in cooling of the deep ocean, which would have allowed for colder temperatures and prolonged glacial periods. Our work during the MPT centers on refining the dynamics of northern-hemisphere ice sheets by utilizing osmium chemo-stratigraphy, bedrock geology adn glacial teill mapping to identify basal bedrock conditions under northern hemisphere ice sheets, and help elucidate ice sheet response to changing basal substrate.

EARTHTIME Integration of the Re-Os Geochronometer

Providing reliable radiometric ages is essential in resolving fundamental problems in earth history. Earthtime is a NSF-funded initiative to produce reliable geochronological ages and develop inter-laboratory standards and calibration. the Rooney Lab has been working on developing reliable standards, inter-laboratory standards calibration and comparison within the EARTHTIME framework.

If you are interested in learning more about these topics and joining the group, I am currentingly looking for motivated and interested students at the graduate level as well as post-docs. Please feel free to contact me at alan(dot)rooney(at)yale(dot)edu.

Research

The Rooney group seeks to understand the relationships between climate, tectonics, ocean geochemistry and evolution during critical transitions in Earth history.

Specifically, we use radiogenic isotope geochemistry in tandem with field geology to constrain interactions between the deep Earth and surface environments and the timing, rates and durations of geological events. n order to address such broad questions, the lab uses a wide-range of approaches (field geology, isotope geochemistry and geochronology).

Pliocene and Pleistocene climate change and ice sheet dynamics

Paleoweathering proxy development and application in the Paleozoic

Understanding the formation and destruction of lower crust in arc settings using radiogenic isotopes

There are opportunities to join an existing NSF-funded project https://www.icdp-online.org/projects/world/global-coverage/grind-ect/

Current Group Members:

Alexie Millikin

Dr Tim Gibson

Facilities

The Rooney Geochronology Clean Lab spaces are part of the Yale Metals Geochemistry Center and are equipped with all-plastic fume hoods, laminar flow benches and casework, centrifuges, manual and semi-automated columns for trace element separation. The center also houses several high sensitivity and precision inductively coupled plasma mass spectrometers. Our analytical capabilities include a Thermo Fisher Neptune-Plus MC-ICP-MS, a Thermo Fisher Triton-Plus TIMS, a Thermo Fisher Element-XR magnetic sector ICP-MS and a Thermo Fisher iCAP TQ ICP-MS. All of the ultra-clean and mass spectrometer laboratories are under positive air-pressure with respect to the building hallways and have controlled temperature and humidity levels. The Geochemistry Center is adjacent to the Microprobe Facility, which houses a JEOL Hyperprobe electron microprobe. Both the Metal Geochemistry Center and the Microprobe Facility have full time technicians.

The department also has and maintains a standard sample preparation facility, which has saws, clean powdering mills, and updated machinery to make thin sections, and a petrography center, which has a scanning electron microscope with a technician and several light microscopes.

People

Dr. Alan Rooney, Assistant Professor

I am interested in understanding the interactions between tectonics, climate processes and geochemical cycles on a range of time scales. I use radiogenic isotope geochemistry, in particular the rhenium-osmium (Re-Os) geochronometer, Sr and Nd isotopes combined with field-based mapping, sedimentology, stratigraphy and mineralogy to interrogate the rock record of critical transitions in Earth History.

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Dr. Jonathan Toma, Postdoctoral Researcher

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Gryphen Goss, Graduate Student

I want to understand how past ice sheets behaved during major climatic shifts. My research involves the application of radiogenic isotope techniques to pinpoint how deglaciation occurred (pulsed/linear), timing, and rate. Major climatic shifts of interests include Mid-Pliocene Warming Period (~ 3 million years ago) and the Mid-Pleistocene Transition (~0.8 million years ago). Specific geochemical techniques I employ include the Re-Os and Sm-Nd isotope systems, with a view to combining these with cosmogenic nuclide dating.

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Sam Shipman, Graduate Student

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Carey Ciaburri, Graduate Student

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Sierra Anseeuw, Lab Manager

I manage the day-to-day lab operations in the Rooney Lab. I received my BS in Environmental Geology from Beloit College and my MS in Geology from the University of Buffalo. My research background is in isotope geochemistry and contaminant hydrogeology

Email Sierra

Contact Info

alan.rooney@yale.edu

+1 (203) 432-3761

Street address: 210 Whitney Ave., New Haven CT 06511

Curriculum Vitae

Publications

Rooney, A.D., Millikin, A.E.,† and Ahlberg, P., 2022. Re-Os geochronology for the Cambrian SPICE event: Insights into euxinia and enhanced continental weathering from radiogenic isotopes. Geology, 50(6), pp.716-720 PDF

Millikin, A.E†., Strauss, J.V., Halverson, G.P., Bergmann, K.D., Tosca, N.J. and Rooney, A.D., 2022. Calibrating the Russøya excursion in Svalbard, Norway, and implications for Neoproterozoic chronology. Geology, 50(4), pp.506-510. PDF

Gibson, T.M†., Millikin, A.E†., Anderson, R.P., Myrow, P.M., Rooney, A.D. and Strauss, J.V., 2021. Tonian deltaic and storm-influenced marine sedimentation on the edge of Laurentia: The Veteranen Group of northeastern Spitsbergen, Svalbard. Sedimentary Geology, 426, p.106011. PDF

Yang, C., Rooney, A.D., Condon, D.J., Li, X.H., Grazhdankin, D.V., Bowyer, F.T., Hu, C., Macdonald, F.A. and Zhu, M., 2021. The tempo of Ediacaran evolution. Science advances, 7(45), p.eabi9643. PDF

Katchinoff, J.A., Syverson, D.D., Planavsky, N.J., Evans, E.S.J.† and Rooney, A.D., 2021. Seawater chemistry and hydrothermal controls on the Cenozoic osmium cycle. Geophysical Research Letters, 48(20), p.e2021GL095558. PDF

Sperling, E.A., Melchin, M.J., Tiffani, F., Stockey, R.G., Farrell, U.C., Bhajan, L., Brunoir, T.N., Cole, D.B., Gill, B.C., Lenz, A., Loydell, D.K., Malinowski, J., Miller, A.J., Plaza-Torres, S., Bock, B., Rooney, A.D., Tecklenburg, S.A., Vogel, J.M., Planavsky, N.J., Strauss, J.V., 2021, A long-term record of early to mid-Paleozoic marine redox change. Science Advances 7, eabf4382 PDF

Busch, J.F., Rooney, A.D., Meyer, E.E., Town, C.F., Moyniham, D.P. and Strauss, J.V., 2021, Late Neoproterozoic - early Paleozoic basin evolution in the Coal Creek inlier of Yukon, Canada: implications for the tectonic evolution of northewestern Laurentia. CJES 99, p.1-23 PDF

Syverson, D.D.,† Katchinoff, J.A.R., Yohe, L.R., Tutolo, B.M., Seyfried, W.E., Rooney, A.D., 2021, Experimental partitioning of osmium between pyrite and fluid: Constraints on the mid-ocean ridge hydrothermal flux of osmium to seawater., Geochimica et Cosmochimica 293, p. 240-255 PDF

Rooney, A.D., Cantine, M.D., Bergman, K.D., Boag, T.H., Busch, J.F., Sperling, E.A., Strauss, J.V., 2020, Calibrating the co-evolution of Ediacaran life and environment, PNAS, 117 p. 16824-16830 PDF

Rainbird, R.H., Rooney, A.D., Creaser, R.A., Skulski, T. 2020, Shale and pyrite Re-Os ages from the Hornby Bay and Amundsen basins provide new chronological markers for Mesoproterozoic stratigraphic successions of northern Canada. Earth and Planetary Science Letters. PDF

Rooney, A.D., Chang, Y., Condon, D.J., Zhu., M and Macdonald, F.A., 2020, U-Pb and Re-Os geochronology tracks stratigraphic condensation in the Sturtian Snowball aftermath, Geology. 48 p. 625-629 PDF

† represents student or postdoc author