Zircon Thermometer Reveals Minimum Melting Conditions on Earliest Earth

@article{Watson2005ZirconTR,
  title={Zircon Thermometer Reveals Minimum Melting Conditions on Earliest Earth},
  author={E. Bruce Watson and T. Mark Harrison},
  journal={Science},
  year={2005},
  volume={308},
  pages={841 - 844}
}
Ancient zircons from Western Australia's Jack Hills preserve a record of conditions that prevailed on Earth not long after its formation. Widely considered to have been a uniquely violent period geodynamically, the Hadean Eon [4.5 to 4.0 billion years ago (Ga)] has recently been interpreted by some as far more benign—possibly even characterized by oceans like those of the present day. Knowledge of the crystallization temperatures of the Hadean zircons is key to this debate. A thermometer based… 
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TLDR
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TLDR
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Constraining the origin and history of very ancient detrital zircons has unique potential for furthering our knowledge of Earth’s very early crust and Hadean geodynamics. Previous applications of the
Insights into the Hadean Earth from experimental studies of zircon
Geologists investigate the evolution of the atmosphere, crust, and mantle through time by direct study of the rock record. However, the Hadean eon (>3.85 Ga) has been traditionally viewed as
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References

SHOWING 1-10 OF 81 REFERENCES
Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago
TLDR
The discovery of a detrital zircon with an age as old as 4,404 ± 8 Myr is reported, about 130 million years older than any previously identified on Earth and represents the earliest evidence for continental crust and oceans on the Earth.
Oxygen-isotope evidence from ancient zircons for liquid water at the Earth's surface 4,300 Myr ago
TLDR
In situ U–Pb and oxygen isotope results for detrital zircons found within 3-Gyr-old quartzitic rocks in the Murchison District of Western Australia are consistent with the presence of a hydrosphere interacting with the crust by 4,300 Myr ago and are postulated to form from magmas containing a significant component of re-worked continental crust.
Jack Hills, evidence of more very old detrital zircons in Western Australia
The age of the Earth's oldest crustal minerals sets a time-limit on the earliest preservation of buoyant solid crust. The oldest mineral ages reported so far are ∼4,180 Myr for detrital zircons from
Nature of the Earth's earliest crust from hafnium isotopes in single detrital zircons
Continental crust forms from, and thus chemically depletes, the Earth's mantle. Evidence that the Earth's mantle was already chemically depleted by melting before the formation of today's oldest
Priscoan (4.00–4.03 Ga) orthogneisses from northwestern Canada
Abstract Ancient crustal rocks provide the only direct evidence for the processes and products of early Earth differentiation. SHRIMP zircon U-Th-Pb dating has identified, amongst the Acasta gneisses
Ion microprobe identification of 4,100–4,200 Myr-old terrestrial zircons
We report here the existence of detrital zircons from Western Australia which are far older than any known terrestrial rocks. They are from quartzites at Mt Narryer (Fig. 1), a locality which has
Low-δ18O Rhyolites from Yellowstone: Magmatic Evolution Based on Analyses of Zircons and Individual Phenocrysts
The Yellowstone Plateau volcanic field is one of the largest centers exchange time to form zoned zircons is between a few hundred and a few thousand years, which reflects the residence time of lowO
Extinct 244Pu in Ancient Zircons
TLDR
Evidence is found for in situ decay of 244Pu in individual 4.1- to 4.2-billion-year-old zircons from the Jack Hills region of Western Australia, which will allow us to date ancient metamorphic events and determine the terrestrial Pu/U ratio for comparison with the solar ratio.
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