Zircon Thermometer Reveals Minimum Melting Conditions on Earliest Earth

  title={Zircon Thermometer Reveals Minimum Melting Conditions on Earliest Earth},
  author={E. Bruce Watson and T. Mark Harrison},
  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… 
Low heat flow inferred from >4 Gyr zircons suggests Hadean plate boundary interactions
An examination of over 400 Hadean zircons from Jack Hills is presented, which shows that some inclusion assemblages are conducive to thermobarometry, and it is suggested that the magmas from which the Jack Hills Hadeans zircon crystallized were formed largely in an underthrust environment, perhaps similar to modern convergent margins.
Hadean Jack Hills Zircon Geochemistry
Geochemical analysis of zircons older than 4 billion years, found in Early Archean metasediments at Jack Hills, Western Australia, provide insights into the nature of Hadean Earth. Oxygen isotopes
The Hadean Crust: Evidence from >4 Ga Zircons
A review of continental growth models leaves open the possibilities that Earth during the Hadean Eon (∼4.5–4.0 Ga) was characterized by massive early crust or essentially none at all. Without support
The Hadean Crust : Evidence from > 4 Ga Zircons
A review of continental growth models leaves open the possibilities that Earth during the Hadean Eon (∼4.5–4.0 Ga) was characterized by massive early crust or essentially none at all. Without support
Hadean diamonds in zircon from Jack Hills, Western Australia
Mineralogical features of the Jack Hills diamonds resemble those of diamonds formed during ultrahigh-pressure metamorphism and imply a relatively thick continental lithosphere and crust–mantle interaction at least 4,250 million years ago.
Impact melt sheet zircons and their implications for the Hadean crust
Impacts may have been important mechanisms of crustal redistribution and differentiation, particularly during intense postaccretionary bombardment between 4.5 Ga and 3.9 Ga ago. Evidence of crustal
Differentiated impact melt sheets may be a potential source of Hadean detrital zircon: Reply
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


Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago
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
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
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.