Roberta Rudnick

Last updated
Roberta Rudnick
Roberta Rudnick.jpg
Born
Roberta L. Rudnick

(1958-08-23) August 23, 1958 (age 64) [1]
Alma mater Portland State University (BS)
Sul Ross State University (MS)
Australian National University (PhD)
SpouseWilliam F. McDonough
Awards Dana Medal (2012)
Harry H. Hess Medal (2017)
Scientific career
Fields
Institutions
Thesis The Nature of the lower continental crust  (1987)
Doctoral advisor Stuart Ross Taylor
Website www.geol.ucsb.edu/people/roberta-rudnick

Roberta L. Rudnick (born 1958) [1] is an American earth scientist and professor of geology at the University of California, Santa Barbara. She was elected a member of the National Academy of Sciences in 2010 and was awarded the Dana Medal by the Mineralogical Society of America. Rudnick is a world expert in the continental crust and lithosphere. [2] [3]

Contents

Early life and education

Rudnick grew up in Portland, Oregon. [4] She completed her undergraduate studies in earth sciences at Portland State University in 1980. [1] [5] She was only fifty miles from the eruption of Mount St. Helens. [4] After graduating, Rudnick moved to Sul Ross State University for her master's degree, specialising in geology. [1] [6] She worked on the geochemistry of metamorphic rocks in Van Horn, Texas. [4] [7] Her master's thesis was titled the Petrography, Geochemistry and Tectonic Affinities of Meta-Igneous Rocks from the Precambrian Carrizo Mountain Group. [8] In 1988, Rudnick earned her PhD at the Australian National University. [1] [9] Her supervisor, Stuart Ross Taylor, studied the upper continental crust. [4] Rudnick was inspired to study the deep crust below, and chose to investigate granulites. [4] She worked out the chemical composition and depths of xenoliths. [10] Whilst she was a student she used the Sensitive high-resolution ion microprobe (SHRIMP) to date ancient zircons. [11] She identified that granulites were depleted in soluble elements. [12]

Research and career

Rudnick was appointed a von Humboldt postdoctoral fellow at the Max Planck Institute for Chemistry in 1987. [1] She returned to the Australian National University as a research fellow in 1989. [1] She worked with Ian Jackson and Dave Fountain on the lower continental crust. [4] [13] In 1994 Rudnick joined Harvard University as assistant professor, before being promoted to Associate in 1997. [1] Her work on the evolution of the continental crust has been cited over one thousand times. [14] It explored the andesitic composition of continental crust that cannot be produced by basaltic magmatism - the building blocks of the continental crust do not match the edifice. [14] There were several theories that explained the depletion; that the foundering of the magnesium and iron-rich lower crust occurs when tectonic plates force the deep crust to recrystallise, that exposure to air and water causes chemical weathering and that the basaltic oceanic crusts melts when it is subducted. [4] Rudnick believes all three theories could explain the paradox of the composition of the crust. [4] During subduction, ocean crust drops down, producing a series of volcanoes that are basaltic at first and later become non-basalt like. [4] High magnesium rocks concentrate at the bottom. [4]

She joined the University of Maryland, College Park, in 2000. [4] When she arrived at Maryland she began to consider the use of lithium isotopes to study near-surface continental processes. [15] She used lithium isotopes to explore the influence of weathering on the composition of the continental crust. [16] Lithium isotopes allowed her to trace recycling in crusts and other diffusional processes in earth. [17] She demonstrated that reactive transport causes kinetic isotope fractionation. [18] [19] She studied ancient glacial tills and demonstrated that ancient continents were rich in iron and magnesium. [20] She also worked on geoneutrinos, helping physicists at the Sudbury Neutrino Observatory and USArray identify whether neutrinos come from the core, mantle or crust of earth. [4]

Rudnick has served as editor-in-chief of Chemical Geology from 2000 to 2010. [21] In 2012 she was made Department Chair. [4] In 2015 Rudnick joined University of California, Santa Barbara as a Professor of Earth Sciences. [22] There she continued work on using isotope fractionation to understand how chemical weathering of the continental crust has evolved alongside changing atmospheric chemistry. [23] She is working on the concentration of heat producing elements (potassium, thorium and uranium) in the continental crust to estimate the Moho temperature. [24]

Awards and honors

Rudnick is a member of the American Academy of Arts and Sciences and a foreign member of the Chinese Academy of Sciences. [17] She has received several large grants from the National Science Foundation. [25] Other awards include:

Related Research Articles

Geochemistry is the science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems such as the Earth's crust and its oceans. The realm of geochemistry extends beyond the Earth, encompassing the entire Solar System, and has made important contributions to the understanding of a number of processes including mantle convection, the formation of planets and the origins of granite and basalt. It is an integrated field of chemistry and geology.

<span class="mw-page-title-main">Andesite</span> Type of volcanic rock

Andesite is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predominantly of sodium-rich plagioclase plus pyroxene or hornblende.

<span class="mw-page-title-main">Anorthosite</span> Mafic intrusive igneous rock composed predominantly of plagioclase

Anorthosite is a phaneritic, intrusive igneous rock characterized by its composition: mostly plagioclase feldspar (90–100%), with a minimal mafic component (0–10%). Pyroxene, ilmenite, magnetite, and olivine are the mafic minerals most commonly present.

<span class="mw-page-title-main">Mantle plume</span> Upwelling of abnormally hot rock within Earths mantle

A mantle plume is a proposed mechanism of convection within the Earth's mantle, hypothesized to explain anomalous volcanism. Because the plume head partially melts on reaching shallow depths, a plume is often invoked as the cause of volcanic hotspots, such as Hawaii or Iceland, and large igneous provinces such as the Deccan and Siberian Traps. Some such volcanic regions lie far from tectonic plate boundaries, while others represent unusually large-volume volcanism near plate boundaries.

<span class="mw-page-title-main">Magnesite</span> Type of mineral

Magnesite is a mineral with the chemical formula MgCO
3. Iron, manganese, cobalt, and nickel may occur as admixtures, but only in small amounts.

<span class="mw-page-title-main">Peridotite</span> Coarse-grained ultramafic igneous rock type

Peridotite ( PERR-ih-doh-tyte, pə-RID-ə-) is a dense, coarse-grained igneous rock consisting mostly of the silicate minerals olivine and pyroxene. Peridotite is ultramafic, as the rock contains less than 45% silica. It is high in magnesium (Mg2+), reflecting the high proportions of magnesium-rich olivine, with appreciable iron. Peridotite is derived from Earth's mantle, either as solid blocks and fragments, or as crystals accumulated from magmas that formed in the mantle. The compositions of peridotites from these layered igneous complexes vary widely, reflecting the relative proportions of pyroxenes, chromite, plagioclase, and amphibole.

<span class="mw-page-title-main">Craton</span> Old and stable part of the continental lithosphere

A craton is an old and stable part of the continental lithosphere, which consists of Earth's two topmost layers, the crust and the uppermost mantle. Having often survived cycles of merging and rifting of continents, cratons are generally found in the interiors of tectonic plates; the exceptions occur where geologically recent rifting events have separated cratons and created passive margins along their edges. Cratons are characteristically composed of ancient crystalline basement rock, which may be covered by younger sedimentary rock. They have a thick crust and deep lithospheric roots that extend as much as several hundred kilometres into Earth's mantle.

<span class="mw-page-title-main">Continental crust</span> Layer of rock that forms the continents and continental shelves

Continental crust is the layer of igneous, metamorphic, and sedimentary rocks that forms the geological continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called sial because its bulk composition is richer in aluminium silicates (Al-Si) and has a lower density compared to the oceanic crust, called sima which is richer in magnesium silicate (Mg-Si) minerals. Changes in seismic wave velocities have shown that at a certain depth, there is a reasonably sharp contrast between the more felsic upper continental crust and the lower continental crust, which is more mafic in character.

<span class="mw-page-title-main">Oceanic crust</span> Uppermost layer of the oceanic portion of a tectonic plate

Oceanic crust is the uppermost layer of the oceanic portion of the tectonic plates. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramafic cumulates. The crust overlies the rigid uppermost layer of the mantle. The crust and the rigid upper mantle layer together constitute oceanic lithosphere.

<span class="mw-page-title-main">Eclogite</span> A dense metamorphic rock formed under high pressure

Eclogite is a metamorphic rock containing garnet (almandine-pyrope) hosted in a matrix of sodium-rich pyroxene (omphacite). Accessory minerals include kyanite, rutile, quartz, lawsonite, coesite, amphibole, phengite, paragonite, zoisite, dolomite, corundum and, rarely, diamond. The chemistry of primary and accessory minerals is used to classify three types of eclogite. The broad range of eclogitic compositions has led a longstanding debate on the origin of eclogite xenoliths as subducted, altered oceanic crust.

A mantle is a layer inside a planetary body bounded below by a core and above by a crust. Mantles are made of rock or ices, and are generally the largest and most massive layer of the planetary body. Mantles are characteristic of planetary bodies that have undergone differentiation by density. All terrestrial planets, a number of asteroids, and some planetary moons have mantles.

<span class="mw-page-title-main">Earth's crust</span> Earths outer shell of rock

Earth's crust is Earth's thick outer shell of rock, referring to less than 1% of the Earth's radius and volume. It is the top component of the lithosphere, a division of Earth's layers that includes the crust and the upper part of the mantle. The lithosphere is broken into tectonic plates whose motion allows heat to escape from the interior of the Earth into space.

In geology, igneous differentiation, or magmatic differentiation, is an umbrella term for the various processes by which magmas undergo bulk chemical change during the partial melting process, cooling, emplacement, or eruption. The sequence of magmas produced by igneous differentiation is known as a magma series.

<span class="mw-page-title-main">Compatibility (geochemistry)</span> Partitioning of elements in a mineral

Compatibility is a term used by geochemists to describe how elements partition themselves in the solid and melt within Earth's mantle. In geochemistry, compatibility is a measure of how readily a particular trace element substitutes for a major element within a mineral.

The Petrological Database of the Ocean Floor (PetDB) is a relational database for global geochemical data on igneous and metamorphic rocks generated at mid-ocean ridges including back-arc basins, young seamounts, and old oceanic crust, as well as ophiolites and terrestrial xenoliths from the mantle and lower crust and diamond geochemistry. These data are obtained by analyses of whole rock powders, volcanic glasses, and minerals by a wide range of techniques including mass spectrometry, atomic emission spectrometry, x-ray fluorescence spectrometry, and wet chemical analyses. Data are compiled from the scientific literature by PetDB data managers, and entered after methodical metadata review. Members of the scientific community can also suggest entry of specific data that has been entered into the EarthChem Library. PetDB is administered by the EarthChem group under the IEDA facility at LDEO headed by K. Lehnert. PetDB is supported by the U.S. National Science Foundation.

<span class="mw-page-title-main">Alkali basalt</span> Type of volcanic rock

Alkali basalt or alkali olivine basalt is a dark-colored, porphyritic volcanic rock usually found in oceanic and continental areas associated with volcanic activity, such as oceanic islands, continental rifts and volcanic fields. Alkali basalt is characterized by relatively high alkali (Na2O and K2O) content relative to other basalts and by the presence of olivine and titanium-rich augite in its groundmass and phenocrysts, and nepheline in its CIPW norm.

<span class="mw-page-title-main">Subcontinental lithospheric mantle</span>

The subcontinental lithospheric mantle (SCLM) is the uppermost solid part of Earth's mantle associated with the continental lithosphere.

<span class="mw-page-title-main">Eastern Block of the North China Craton</span>

The Eastern Block of the North China Craton is one of the Earth's oldest pieces of continent. It is separated from the Western Block by the Trans-North China Orogen. It is situated in northeastern China and North Korea. The Block contains rock exposures older than 2.5 billion years. It serves as an ideal place to study how the crust was formed in the past and the related tectonic settings.

Stanley Robert Hart is an American geologist, geochemist, leading international expert on mantle isotope geochemistry, and pioneer of chemical geodynamics.

Catherine Chauvel is a geochemist at the Institut de Physique du Globe de Paris known for her research on the impact of volcanic activity on the chemistry of the mantle, continental crust, and island arc geochemistry.

References

  1. 1 2 3 4 5 6 7 8 "Roberta L". geol.umd.edu. Retrieved 2018-08-12.
  2. 1 2 Roberta Rudnick publications indexed by Google Scholar OOjs UI icon edit-ltr-progressive.svg
  3. ↑ Roberta Rudnick publications indexed by the Scopus bibliographic database. (subscription required)
  4. 1 2 3 4 5 6 7 8 9 10 11 12 13 Downey, Philip (2012). "Profile of Roberta L. Rudnick". Proceedings of the National Academy of Sciences. 109 (49): 19873–19875. Bibcode:2012PNAS..10919873D. doi: 10.1073/pnas.1219069109 . ISSN   0027-8424. PMC   3523877 . PMID   23169649.
  5. ↑ "Portland State College of Liberal Arts & Sciences: Department of Geology | Alumni M through Z". pdx.edu. Retrieved 2018-08-12.
  6. ↑ "GOOD NEWS: Sul Ross honors athletic standouts, distinguished alumni". Odessa American. Retrieved 2018-08-12.
  7. ↑ Rudnick, Roberta L. (1983). "Geochemistry and tectonic affinities of a Proterozoic bimodal igneous suite, west Texas". Geology. 11 (6): 352–355. Bibcode:1983Geo....11..352R. doi:10.1130/0091-7613(1983)11<352:gataoa>2.0.co;2. ISSN   0091-7613.
  8. ↑ "Sul Ross State University, Fifty-Eighth Annual Commencement" (PDF). Sul Ross University. 1983-05-13. Retrieved 2018-08-11.
  9. ↑ Rudnick, Roberta L. (1987). The nature of the lower continental crust (PhD thesis). Australian National University. OCLC   222186796.
  10. ↑ Rudnick, R. L.; Taylor, S. R. (1987). "The composition and petrogenesis of the lower crust: A xenolith study". Journal of Geophysical Research: Solid Earth. 92 (B13): 13981–14005. Bibcode:1987JGR....9213981R. doi:10.1029/jb092ib13p13981. ISSN   0148-0227.
  11. ↑ authors, various (1987). "Dating the lower crust by ion microprobe". Earth and Planetary Science Letters. 85 (1–3): 145–161. Bibcode:1987E&PSL..85..145R. doi:10.1016/0012-821X(87)90028-8. ISSN   0012-821X.
  12. ↑ authors, Various (1985). "Large ion lithophile elements in rocks from high-pressure granulite facies terrains". Geochimica et Cosmochimica Acta. 49 (7): 1645–1655. Bibcode:1985GeCoA..49.1645R. doi:10.1016/0016-7037(85)90268-6. ISSN   0016-7037.
  13. ↑ Rudnick, Roberta L.; Fountain, David M. (1995). "Nature and composition of the continental crust: A lower crustal perspective". Reviews of Geophysics. 33 (3): 267. Bibcode:1995RvGeo..33..267R. doi:10.1029/95rg01302. ISSN   8755-1209.
  14. 1 2 Rudnick, Roberta L. (1995). "Making continental crust". Nature. 378 (6557): 571–578. Bibcode:1995Natur.378..571R. doi:10.1038/378571a0. ISSN   0028-0836. S2CID   4312218.
  15. 1 2 "Roberta Rudnick Receives 2017 Harry H. Hess Medal - Eos". Eos.org. Retrieved 2018-08-12.
  16. ↑ Liu, Xiao-Ming; Rudnick, Roberta L. (2011). "Constraints on continental crustal mass loss via chemical weathering using lithium and its isotopes". Proceedings of the National Academy of Sciences. 108 (52): 20873–20880. Bibcode:2011PNAS..10820873L. doi: 10.1073/pnas.1115671108 . ISSN   0027-8424. PMC   3248527 . PMID   22184221.
  17. 1 2 "Meeting Information". www.aps.org. Retrieved 2018-08-12.
  18. ↑ Teng, Fang-Zhen; Watkins, James; Dauphas, Nicolas (2017-03-06). Non-Traditional Stable Isotopes. Walter de Gruyter GmbH & Co KG. ISBN   9783110545630.
  19. ↑ Teng, Fang-Zhen; Yang, Wei; Rudnick, Roberta L.; Hu, Yan (2013). "Heterogeneous magnesium isotopic composition of the lower continental crust: A xenolith perspective". Geochemistry, Geophysics, Geosystems. 14 (9): 3844–3856. Bibcode:2013GGG....14.3844T. doi:10.1002/ggge.20238. ISSN   1525-2027.
  20. ↑ Gaschnig, Richard M.; Rudnick, Roberta L.; McDonough, William F.; Kaufman, Alan J.; Valley, John W.; Hu, Zhaochu; Gao, Shan; Beck, Michelle L. (2016-08-01). "Compositional evolution of the upper continental crust through time, as constrained by ancient glacial diamictites" (PDF). Geochimica et Cosmochimica Acta. 186: 316–343. Bibcode:2016GeCoA.186..316G. doi: 10.1016/j.gca.2016.03.020 . ISSN   0016-7037.
  21. ↑ Elsevier. "Editor-In-Chief of Chemical Geology, Professor Roberta Rudnick, Elected to NAS". www.elsevier.com. Retrieved 2018-08-12.
  22. ↑ "Robin Matoza and Roberta Rudnick join the Department faculty! | Earth Science - UC Santa Barbara". geol.ucsb.edu. Retrieved 2018-08-12.
  23. ↑ Greaney, Allison T.; Rudnick, Roberta L.; Romaniello, Stephen J.; Johnson, Aleisha C.; Gaschnig, Richard M.; Anbar, Ariel D. (2020-03-15). "Molybdenum isotope fractionation in glacial diamictites tracks the onset of oxidative weathering of the continental crust". Earth and Planetary Science Letters. 534: 116083. Bibcode:2020E&PSL.53416083G. doi: 10.1016/j.epsl.2020.116083 . ISSN   0012-821X. S2CID   212932603.
  24. ↑ "NSF Award Search: Award#1650260 - U-Pb Thermochronology of Lower Crustal Xenoliths: Estimating Moho Temperature in Order to Constrain Crustal Heat Production". nsf.gov. Retrieved 2018-08-12.
  25. ↑ rudnicks ORCID   0000-0003-1559-7463
  26. ↑ "Rudnick Receives 2006 N. L. Bowen Award - Honors Program". Honors Program. Retrieved 2018-08-12.
  27. ↑ "Roberta Rudnick". nasonline.org. National Academy of Sciences -. Retrieved 2018-08-12.
  28. ↑ "Mineralogical Society of America - Dana Medal". minsocam.org. Retrieved 2018-08-12.
  29. ↑ Hofmann, Albrecht (2012). "Presentation of the Dana Medal of the Mineralogical Society of America for 2012 to Roberta L. Rudnick". American Mineralogist. 97 (10): 1816. Bibcode:2012AmMin..97.1816H. doi:10.2138/am.2012.598. ISSN   0003-004X. Closed Access logo transparent.svg
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