Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.
Zircon Thermometer Reveals Minimum Melting Conditions on Earliest Earth
E. B. Watson1* and
T. M. Harrison2,3
Ancient zircons from Western Australia's Jack Hills preservea record of conditions that prevailed on Earth not long afterits formation. Widely considered to have been a uniquely violentperiod geodynamically, the Hadean Eon [4.5 to 4.0 billion yearsago (Ga)] has recently been interpreted by some as far morebenign—possibly even characterized by oceans like thoseof the present day. Knowledge of the crystallization temperaturesof the Hadean zircons is key to this debate. A thermometer basedon titanium content revealed that these zircons cluster stronglyat 700°C, which is indistinguishable from temperatures ofgranitoid zircon growth today and strongly suggests a regulatedmechanism producing zircon-bearing rocks during the Hadean.The temperatures substantiate the existence of wet, minimum-meltingconditions within 200 million years of solar system formation.They further suggest that Earth had settled into a pattern ofcrust formation, erosion, and sediment recycling as early as4.35 Ga.
1 Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA. 2 Research School of Earth Sciences, Australian National University, Canberra, ACT 2601, Australia. 3 Department of Earth and Space Sciences and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90095, USA.
* To whom correspondence should be addressed. E-mail: watsoe{at}rpi.edu
The editors suggest the following Related Resources on Science sites:
In Science Magazine
TECHNICAL COMMENTS
Andrew Glikson (10 February 2006) Science311 (5762), 779a.
[DOI: 10.1126/science.1120073] |Abstract »|Full Text »|PDF »
TECHNICAL COMMENTS
Allen P. Nutman (10 February 2006) Science311 (5762), 779b.
[DOI: 10.1126/science.1120977] |Abstract »|Full Text »|PDF »
TECHNICAL COMMENTS
E. B. Watson and T. M. Harrison (10 February 2006) Science311 (5762), 779c.
[DOI: 10.1126/science.1121080] |Abstract »|Full Text »|PDF »
THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Primitive oxygen-isotope ratio recorded in magmatic zircon from the Mid-Atlantic Ridge.
A. J. Cavosie, N. T. Kita, and J. W. Valley (2009)
American Mineralogist
94, 926-934
|Abstract »|Full Text »|PDF »
Igneous, Alteration and Exhumation Processes Recorded in Abyssal Peridotites and Related Fault Rocks from an Oceanic Core Complex along the Central Indian Ridge.
T. Morishita, K. Hara, K. Nakamura, T. Sawaguchi, A. Tamura, S. Arai, K. Okino, K. Takai, and H. Kumagai (2009)
J. Petrology
|Abstract »|Full Text »|PDF »
Mineral-scale Trace Element and U-Th-Pb Age Constraints on Metamorphism and Melting during the Petermann Orogeny (Central Australia).
C. J. Gregory, I. S. Buick, J. Hermann, and D. Rubatto (2009)
J. Petrology
|Abstract »|Full Text »|PDF »
U-Pb age, trace-element, and Hf-isotope compositions of zircon in a quartz vein from eclogite in the western Dabie Mountains: Constraints on fluid flow during early exhumation of ultrahigh-pressure rocks.
Y.-B. Wu, S. Gao, H.-F. Zhang, S.-H. Yang, X.-C. Liu, W.-F. Jiao, Y.-S. Liu, H.-L. Yuan, H.-J. Gong, and M.-C. He (2009)
American Mineralogist
94, 303-312
|Abstract »|Full Text »|PDF »
High- and ultrahigh-pressure metamorphism: Past results and future prospects.
The Spirit Mountain batholith and Secret Pass Canyon volcanic center: A cross-sectional view of the magmatic architecture of the uppermost crust of an extensional terrain, Colorado River, Nevada-Arizona.
N. P. Lang, B.J. Walker, L. L. Claiborne, C. F. Miller, R. W. Hazlett, and M. T. Heizler (2008)
Field Guides
11, 187-214
|Abstract »|Full Text »|PDF »
Empirical thermometer of TiO2 in quartz for ultrahigh-temperature granulites of East Antarctica.
T. Kawasaki and Y. Osanai (2008)
Geological Society, London, Special Publications
308, 419-430
|Abstract »|Full Text »|PDF »
Zircon Inheritance Reveals Exceptionally Fast Crustal Magma Generation Processes in Central Iberia during the Cambro-Ordovician.
F. Bea, P. Montero, F. Gonzalez-Lodeiro, and C. Talavera (2007)
J. Petrology
48, 2327-2339
|Abstract »|Full Text »|PDF »
Temperature spectra of zircon crystallization in plutonic rocks.
Tracking magmatic processes through Zr/Hf ratios in rocks and Hf and Ti zoning in zircons: An example from the Spirit Mountain batholith, Nevada.
L. L. Claiborne, C. F. Miller, B. A. Walker, J. L. Wooden, F. K. Mazdab, and F. Bea (2006)
Mineralogical Magazine
70, 517-543
|Abstract »|Full Text »|PDF »
Temperature and Bulk Composition Control on the Growth of Monazite and Zircon During Low-pressure Anatexis (Mount Stafford, Central Australia).
Zircon thermometry and U-Pb ion-microprobe dating of the gabbros and associated migmatites of the Variscan Toledo Anatectic Complex, Central Iberia.
F. Bea, P.G. Montero, F. Gonzalez-Lodeiro, C. Talavera, J.F. Molina, J.H. Scarrow, M.J. Whitehouse, and T. Zinger (2006)
Journal of the Geological Society
163, 847-855
|Abstract »|Full Text »|PDF »
700°C, which is indistinguishable from temperatures of granitoid zircon growth today and strongly suggests a regulated mechanism producing zircon-bearing rocks during the Hadean. The temperatures substantiate the existence of wet, minimum-melting conditions within 200 million years of solar system formation. They further suggest that Earth had settled into a pattern of crust formation, erosion, and sediment recycling as early as 4.35 Ga. 
