page_title: Hadean zircon
section_title: Properties
hierarchical_section_title: Hadean zircon / Properties
caption_attribution_description: English: U-Pb dating
context_page_description: Hadean zircon is the oldest-surviving crustal material from the Earth's earliest geological time period, the Hadean eon, about 4 billion years ago. Zircon is a mineral that is commonly used for radiometric dating because it is highly resistant to chemical changes and appears in the form of small crystals or grains in most igneous and metamorphic host rocks.
  Hadean zircon has very low abundance around the globe because of recycling of material by plate tectonics. When the rock at the surface is buried deep in the Earth it is heated and can recrystallise or melt. In the Jack Hills, Australia, scientists obtained a relatively comprehensive record of Hadean zircon crystals in contrast to other locations. The Jack Hills rocks are from the Archean eon, about 3.6 billion years old. However, the zircon crystals there are older than the rocks that contain them. Many investigations have been carried out to find the absolute age and properties of zircon, for example the isotope ratios, mineral inclusions, and geochemistry of zircon. The characteristics of Hadean zircons show early Earth history and the mechanism of Earth's processes in the past.
context_section_description: The unspecified samples used for analyses below were Jack Hills zircon in Australia because of the high abundances and data available.
caption: Histograms for concordant Jack Hills zircons. This is a histogram of rapid initial survey of individual 207Pb/206Pb ages undertaken to identify the >4.2Ga population. There are 3 dominant peaks and 2 minor peaks.[15]
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