Anat Shahar

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Anat Shahar is a staff scientist at the Earth and Planets Laboratory, Carnegie Institution of Washington [1] and adjunct professor at the University of Maryland. [2] Her work uses high-pressure, high-temperature experiments and stable isotope geochemistry to understand the formation of planets in the Solar System. [3]

Contents

Early Life

Anat Shahar was born in Israel on April 10, 1980. She moved then moved to New Jersey at age 6.

Career

Shahar obtained a B.S. and a M.E. in geological engineering from Cornell University in 2002 and 2003, respectively. She earned her Ph.D. in geochemistry from the University of California, Los Angeles in 2008, while working in the lab of Edward Young. She went on to complete her postdoctoral research at the geophysical laboratory, Carnegie Institution of Washington and in 2009 was appointed staff scientist. Since 2012 she also has served as an adjunct assistant professor in the department of geology at the University of Maryland. [4]

Shahar was awarded the Nininger Meteorite Award, which recognizes outstanding student achievement in the meteoritical sciences, for her 2008 paper on "Astrophysics of CAI formation as revealed by silicon isotope LA-MC-ICPMS of an igneous CAI". [5] [6] In 2012 Shahar was awarded Stanford University's Blaustein Fellowship, which helped fund her work investigating the pressure-dependent relationship of the isotopic composition of iron alloys, published in Science . [7] [8] [9] In 2015, Shahar won the F.W. Clarke Medal, an award from the Geochemical Society that recognizes a single outstanding contribution to geochemistry or cosmochemistry by an early-career scientist. [10] Shahar won the 2016 Mineralogical Society of America's Young Investigator Award, given to individuals near the beginning of their professional careers, who have made outstanding published contributions to the field of mineralogy. The award also made her a Life Fellow of the society. [11] Shahar also served as geochemistry secretary for the Volcanology, Geochemistry, and Petrology Section of the American Geophysical Union during 2017-2018. [12] [13]

Research initiatives

In her research, Shahar investigates how planets in the solar system formed and evolved through lab experiments that simulate the high temperature and pressure conditions that occur within Earth and other planets. She is the first person to perform stable isotope geochemistry experiments with high-temperature materials. [14] Her lab group determines how these conditions alter the ratios of isotopes in different planetary materials. Shahar utilizes this method to understand planetary processes ranging from the formation of the first solids in the solar system, CAIs, to core formation. [6] [15] [16]

Shahar measured the silicon isotope fractionation during silicate and iron interaction in experiments that simulate the formation of a metallic core and surrounding mantle, such as occurred during Earth's formation. The experiments suggest that silicon may be one of the lighter elements that make up Earth’s core, along with iron and nickel. [15] [17] Shahar’s lab group also investigates how the presence of magnesium, sulfur, and nickel [18] affect iron isotopic fractionation in planetary and asteroid materials. [19]

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">Earth's outer core</span> Fluid layer composed of mostly iron and nickel between Earths solid inner core and its mantle

Earth's outer core is a fluid layer about 2,260 km (1,400 mi) thick, composed of mostly iron and nickel that lies above Earth's solid inner core and below its mantle. The outer core begins approximately 2,889 km (1,795 mi) beneath Earth's surface at the core-mantle boundary and ends 5,150 km (3,200 mi) beneath Earth's surface at the inner core boundary.

<span class="mw-page-title-main">Planetary differentiation</span> Astrogeological concept

In planetary science, planetary differentiation is the process by which the chemical elements of a planetary body accumulate in different areas of that body, due to their physical or chemical behavior. The process of planetary differentiation is mediated by partial melting with heat from radioactive isotope decay and planetary accretion. Planetary differentiation has occurred on planets, dwarf planets, the asteroid 4 Vesta, and natural satellites.

<span class="mw-page-title-main">Chondrite</span> Class of stony meteorites made of round grains

A chondrite is a stony (non-metallic) meteorite that has not been modified, by either melting or differentiation of the parent body. They are formed when various types of dust and small grains in the early Solar System accreted to form primitive asteroids. Some such bodies that are captured in the planet's gravity well become the most common type of meteorite by arriving on a trajectory toward the planet's surface. Estimates for their contribution to the total meteorite population vary between 85.7% and 86.2%.

<span class="mw-page-title-main">Planetary core</span> Innermost layer(s) of a planet

A planetary core consists of the innermost layers of a planet. Cores may be entirely solid or entirely liquid, or a mixture of solid and liquid layers as is the case in the Earth. In the Solar System, core sizes range from about 20% to 85% of a planet's radius (Mercury).

<span class="mw-page-title-main">Troilite</span> Rare iron sulfide mineral: FeS

Troilite is a rare iron sulfide mineral with the simple formula of FeS. It is the iron-rich endmember of the pyrrhotite group. Pyrrhotite has the formula Fe(1-x)S which is iron deficient. As troilite lacks the iron deficiency which gives pyrrhotite its characteristic magnetism, troilite is non-magnetic.

<span class="mw-page-title-main">Fractional crystallization (geology)</span> Process of rock formation

Fractional crystallization, or crystal fractionation, is one of the most important geochemical and physical processes operating within crust and mantle of a rocky planetary body, such as the Earth. It is important in the formation of igneous rocks because it is one of the main processes of magmatic differentiation. Fractional crystallization is also important in the formation of sedimentary evaporite rocks or simply fractional crystallization is the removal of early formed crystals from an Original homogeneous magma so that the crystals are prevented from further reaction with the residual melt.

<span class="mw-page-title-main">Internal structure of the Moon</span>

Having a mean density of 3,346.4 kg/m3, the Moon is a differentiated body, being composed of a geochemically distinct crust, mantle, and planetary core. This structure is believed to have resulted from the fractional crystallization of a magma ocean shortly after its formation about 4.5 billion years ago. The energy required to melt the outer portion of the Moon is commonly attributed to a giant impact event that is postulated to have formed the Earth-Moon system, and the subsequent reaccretion of material in Earth orbit. Crystallization of this magma ocean would have given rise to a mafic mantle and a plagioclase-rich crust.

CI chondrites, also called C1 chondrites or Ivuna-type carbonaceous chondrites, are a group of rare carbonaceous chondrite, a type of stony meteorite. They are named after the Ivuna meteorite, the type specimen. CI chondrites have been recovered in France, Canada, India, and Tanzania. Their overall chemical composition closely resembles the elemental composition of the Sun, more so than any other type of meteorite.

<span class="mw-page-title-main">Lodranite</span> Type of meteorites

Lodranites are a small group of primitive achondrite meteorites that consists of meteoric iron and silicate minerals. Olivine and pyroxene make up most of the silicate minerals. Like all primitive achondrites lodranites share similarities with chondrites and achondrites.

<span class="mw-page-title-main">Nonmagmatic meteorite</span> Deprecated term formerly used in meteoritics

Nonmagmatic meteorite is a deprecated term formerly used in meteoritics to describe iron meteorites that were originally thought to have not formed by igneous processes, to differentiate them from the magmatic meteorites, produced by the crystallization of a metal melt. The concept behind this was developed in the 1970s, but it was quickly realized that igneous processes actually play a vital role in the formation of the so-called "nonmagmatic" meteorites. Today, the terms are still sometimes used, but usage is discouraged because of the ambiguous meanings of the terms magmatic and nonmagmatic. The meteorites that were described to be nonmagmatic are now understood to be the product of partial melting and impact events and are grouped with the primitive achondrites and the achondrites.

<span class="mw-page-title-main">Titanium in zircon geothermometry</span>

Titanium in zircon geothermometry is a form of a geothermometry technique by which the crystallization temperature of a zircon crystal can be estimated by the amount of titanium atoms which can only be found in the crystal lattice. In zircon crystals, titanium is commonly incorporated, replacing similarly charged zirconium and silicon atoms. This process is relatively unaffected by pressure and highly temperature dependent, with the amount of titanium incorporated rising exponentially with temperature, making this an accurate geothermometry method. This measurement of titanium in zircons can be used to estimate the cooling temperatures of the crystal and infer conditions during which it crystallized. Compositional changes in the crystals growth rings can be used to estimate the thermodynamic history of the entire crystal. This method is useful as it can be combined with radiometric dating techniques that are commonly used with zircon crystals, to correlate quantitative temperature measurements with specific absolute ages. This technique can be used to estimate early Earth conditions, determine metamorphic facies, or to determine the source of detrital zircons, among other uses.

Although diamonds on Earth are rare, extraterrestrial diamonds are very common. Diamonds small enough that they contain only about 2000 carbon atoms are abundant in meteorites and some of them formed in stars before the Solar System existed. High pressure experiments suggest large amounts of diamonds are formed from methane on the ice giant planets Uranus and Neptune, while some planets in other planetary systems may be almost pure diamond. Diamonds are also found in stars and may have been the first mineral ever to have formed.

<span class="mw-page-title-main">Lutetium–hafnium dating</span> Gochronological dating method utilizing the radioactive decay system of lutetium–176

Lutetium–hafnium dating is a geochronological dating method utilizing the radioactive decay system of lutetium–176 to hafnium–176. With a commonly accepted half-life of 37.1 billion years, the long-living Lu–Hf decay pair survives through geological time scales, thus is useful in geological studies. Due to chemical properties of the two elements, namely their valences and ionic radii, Lu is usually found in trace amount in rare-earth element loving minerals, such as garnet and phosphates, while Hf is usually found in trace amount in zirconium-rich minerals, such as zircon, baddeleyite and zirkelite.

The geochemistry of carbon is the study of the transformations involving the element carbon within the systems of the Earth. To a large extent this study is organic geochemistry, but it also includes the very important carbon dioxide. Carbon is transformed by life, and moves between the major phases of the Earth, including the water bodies, atmosphere, and the rocky parts. Carbon is important in the formation of organic mineral deposits, such as coal, petroleum or natural gas. Most carbon is cycled through the atmosphere into living organisms and then respirated back into the atmosphere. However an important part of the carbon cycle involves the trapping of living matter into sediments. The carbon then becomes part of a sedimentary rock when lithification happens. Human technology or natural processes such as weathering, or underground life or water can return the carbon from sedimentary rocks to the atmosphere. From that point it can be transformed in the rock cycle into metamorphic rocks, or melted into igneous rocks. Carbon can return to the surface of the Earth by volcanoes or via uplift in tectonic processes. Carbon is returned to the atmosphere via volcanic gases. Carbon undergoes transformation in the mantle under pressure to diamond and other minerals, and also exists in the Earth's outer core in solution with iron, and may also be present in the inner core.

<span class="mw-page-title-main">Deep carbon cycle</span> Movement of carbon through Earths mantle and core

The deep carbon cycle is geochemical cycle (movement) of carbon through the Earth's mantle and core. It forms part of the carbon cycle and is intimately connected to the movement of carbon in the Earth's surface and atmosphere. By returning carbon to the deep Earth, it plays a critical role in maintaining the terrestrial conditions necessary for life to exist. Without it, carbon would accumulate in the atmosphere, reaching extremely high concentrations over long periods of time.

CM chondrites are a group of chondritic meteorites which resemble their type specimen, the Mighei meteorite. The CM is the most commonly recovered group of the 'carbonaceous chondrite' class of meteorites, though all are rarer in collections than ordinary chondrites.

Hafnium–tungsten dating is a geochronological radiometric dating method utilizing the radioactive decay system of hafnium-182 to tungsten-182. The half-life of the system is 8.9±0.1 million years. Today hafnium-182 is an extinct radionuclide, but the hafnium–tungsten radioactive system is useful in studies of the early Solar system since hafnium is lithophilic while tungsten is moderately siderophilic, which allows the system to be used to date the differentiation of a planet's core. It is also useful in determining the formation times of the parent bodies of iron meteorites.

Nicolas Dauphas is a planetary scientist and isotope geochemist. He is a professor of geochemistry and cosmochemistry in the Department of the Geophysical Sciences and Enrico Fermi Institute at the University of Chicago, where he was previously a Louis Block professor, being appointed to that professorship in 2016. His research focuses on isotope geochemistry and cosmochemistry. He studies the origin and evolution of planets and other objects in the solar system by analyzing the natural distributions of elements and their isotopes using mass spectrometers.

Hugh Pettingill Taylor Jr. was an American geochemist.

References

  1. ↑ "Shahar". Geophysical Laboratory. 2016-06-17. Retrieved 2018-10-31.
  2. ↑ "Anat Shahar | Department of Geology". geol.umd.edu. Retrieved 2018-10-31.
  3. ↑ "Anat Shahar". carnegiescience.edu. Carnegie Institution for Science. 2014-11-10. Retrieved 2017-12-29.
  4. ↑ "Anat Shahar - CV". sites.google.com. Retrieved 2017-12-29.
  5. ↑ "Center for Meteorite Studies | Founded 1961" (PDF). meteorites.asu.edu. Archived from the original (PDF) on 2017-09-08. Retrieved 2018-12-05.
  6. 1 2 Shahar, A.; Young, E. (2007-05-30). "Astrophysics of CAI formation as revealed by silicon isotope LA-MC-ICPMS of an igneous CAI". Earth and Planetary Science Letters. 257 (3–4): 497–510. Bibcode:2007E&PSL.257..497S. doi:10.1016/j.epsl.2007.03.012. ISSN   0012-821X.
  7. ↑ Mao, W.; Shu, J.; Xiao, Y.; Reagan, M. M.; Gleason, A. E.; Caracas, R.; Schauble, E. A.; Shahar, A. (2016-04-29). "Pressure-dependent isotopic composition of iron alloys". Science. 352 (6285): 580–582. Bibcode:2016Sci...352..580S. doi: 10.1126/science.aad9945 . ISSN   1095-9203. PMID   27126042.
  8. ↑ "Geochemical detectives use lab mimicry to look back in time". EurekAlert!. Retrieved 2018-12-05.
  9. ↑ "Crushing Pressures Start to Reveal the Truth about Earth's Core | Advanced Photon Source". aps.anl.gov. Archived from the original on 2018-12-06. Retrieved 2018-12-05.
  10. ↑ "Anat Shahar named 2015 F.W. Clarke Medalist". geochemsoc.org. Archived from the original on 2018-09-10. Retrieved 2017-12-29.
  11. ↑ "Mineralogical Society of America - MSA Award". minsocam.org. Retrieved 2017-12-29.
  12. ↑ "Leadership - Volcanology, Geochemistry, and Petrology". Volcanology, Geochemistry, and Petrology. Retrieved 2017-12-29.
  13. ↑ "Resources - VGP". connect.agu.org. Retrieved 2022-01-10.
  14. ↑ Than, Ker. "Crushing Pressures Start to Reveal the Truth About Earth's Core". Smithsonian. Retrieved 2017-12-29.
  15. 1 2 Shahar, Anat; Ziegler, Karen; Young, Edward D.; Ricolleau, Angele; Schauble, Edwin A.; Fei, Yingwei (2009-10-30). "Experimentally determined Si isotope fractionation between silicate and Fe metal and implications for Earth's core formation". Earth and Planetary Science Letters. 288 (1–2): 228–234. Bibcode:2009E&PSL.288..228S. doi:10.1016/j.epsl.2009.09.025.
  16. ↑ Shahar, Anat; Hillgren, Valerie J.; Young, Edward D.; Fei, Yingwei; MacRis, Catherine A.; Deng, Liwei (2011-12-01). "High-temperature Si isotope fractionation between iron metal and silicate". Geochimica et Cosmochimica Acta. 75 (23): 7688–7697. Bibcode:2011GeCoA..75.7688S. doi:10.1016/j.gca.2011.09.038. ISSN   0016-7037.
  17. ↑ Young, Edward (5 May 2017). "Presentation of the Mineralogical Society of America Award for 2016 to Anat Shahar" (PDF). American Mineralogist. Retrieved December 29, 2017.
  18. ↑ "Nickel helps scientists iron out a core planetary mystery | Cosmos". cosmosmagazine.com. Retrieved 2017-12-29.
  19. ↑ "Anat Shahar - Research". sites.google.com. Retrieved 2017-12-29.

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