* Astronomy

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RE: Chicxulub event

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The asteroid impact that many researchers claim was the cause of the dinosaur die-off was bad news for marine life at the time as well. But new research shows that microalgae - one of the primary producers in the ocean - bounced back from the global extinction in about 100 years or less.

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In the hills behind the historic homestead in Waipara, north Canterbury, about 45 minutes drive north of Christchurch in the South Island, are limestone canyons and riverbeds yielding precious remnants of that catastrophic event when New Zealand was still under the ocean.
The Waipara riverbed is rich in the element iridium, also found mainly in Denmark and Italy. Iridium is rare on earth but abundant in meteorites.
Scattered across the Waipara property are massive rounded rocks, weighing over a tonne each, which Goord calls God's marbles.
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The asteroid impact that ended the age of dinosaurs 65 million years ago didn't incinerate life on our planet's surface - it just broiled it, a new study suggests. The work resolves nagging questions about a theory that the impact triggered deadly wildfires around the world, but it also raises new questions about just what led to the mass extinction at the end of the Cretaceous period.
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Title: Re-igniting the Cretaceous-Palaeogene firestorm debate
Authors: Claire M. Belcher

Nearly 30 yr since Alvarez et al. (1980) detected an enrichment of iridium at the Cretaceous-Palaeogene (K-Pg) boundary (65 Ma), the events that lead to the demise of the dinosaurs have become a feature of considerable scientific and public debate. It is generally accepted that an extraterrestrial body collided with the Earth 65 m.y. ago and that the 200-km-wide Chicxulub Crater on the Yucatan Peninsula, Mexico, is the mark of this impact (Hildebrand et al., 1991). This impact blasted melted asteroidal and target rock debris across the planet, depositing the K-Pg boundary impact rock layers. The environmental consequences of the impact, and particularly the amount of thermal radiation it delivered, remain the hottest topic of the K-Pg debate.

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K-T boundary

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RE: Chicxulub event

Blobrana · L

Credit: NASA/JPL/NGA

The topography of Mexico's Yucatan Peninsula reveals a subtle, but unmistakable, indication of the Chicxulub asteroid impact crater, believed by many scientists to be the cause of a mass extinction event 65 million years ago. In this computer-enhanced image, the crater's outer boundary is visible as the semi-circular, darker green line in the peninsula's upper left corner: a trough only 3 to 5 metres deep and 5 kilometres wide.

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Blobrana · L

The extraterrestrial body that slammed into Earth 65 million years ago is best known for killing off the dinosaurs. But it also snuffed out more than 90% of the tiny plankton species that made up the base of the food web in the oceans. By sifting through geological records of ancient sediments from around the globe, palaeoceanographers have culled clues about how the impact caused so much havoc.
The researchers report in Nature Geoscience1 today that the most severe extinctions of nannoplankton happened in the northern oceans and that the ecosystems there took 300,000 years to recover, much longer than in the south.
Geological evidence suggests that the body that hit Earth was travelling from the southeast to the northwest.
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Dinosaur extinction link to crater confirmed

An international panel of experts has strongly endorsed evidence that a space impact was behind the mass extinction event that killed off the dinosaurs.
They reached the consensus after conducting the most wide-ranging analysis yet of the evidence.
Writing in Science journal, they rule out alternative theories such as large-scale volcanism.
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