On the basis of these crystals the researchers have gained important new insights into the history of the moon's development. Their results are presented in the latest issue of the prestigious Nature Geoscience magazine.
Dr. Thorsten Geisler-Wierwille from the Institute of Mineralogy at the University of Münster has been examining tiny zircon crystals with his colleagues from Australia and the USA. The crystals come from moonrock already collected 36 years ago on the Apollo 17 mission. With the the help of modern microanalytical processes and uranium-lead dating the scientists have ascertained the age of the crystals. The oldest zircon they found is about 4.4 billion years old.
This very precise dating of the crystals' age enables the scientists to reconstruct for the first time, and more accurately, the crystallization and cooling history of the magma ocean on the moon. This magma ocean was formed after a collision around 4.5 billion years ago between the young Earth and a proto-planet the size of Mars.
"Any reconstruction of the cooling history was only possible to a limited extent before this," says Geisler-Wierwille, "because isotope systems that could have been used to ascertain age were badly damaged by intense meteorite impacts on the moon around 3.9 billion years ago. However, the uranium-lead dating system is very stable in the face of extreme pressures and temperatures and is therefore highly suitable for establishing how long ago things were formed."
The crystallization of zircon in the lunar magma indicates that at this point there was only a small quantity of magma still in existence. The scientists conclude that almost the entire magma ocean was solidified 100 million years after the moon was formed.
Dr. Geisler-Wierwille made the headlines once before with the discovery of especially old crystals. He and Martina Menneken from the WWU's Institute of Mineralogy belong to a team of researchers who in 2007 found the oldest diamonds in the world.
Dr. Christina Heimken | idw
In times of climate change: What a lake’s colour can tell about its condition
21.09.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
Did marine sponges trigger the ‘Cambrian explosion’ through ‘ecosystem engineering’?
21.09.2017 | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
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22.09.2017 | Physics and Astronomy
22.09.2017 | Physics and Astronomy