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RE: Supernova link to Rancholabrean fauna extinction?

Another East Coast interest of mine!

I would be very grateful if someone with access to this could send me a PDF
of it. 


 Thomas R. Lipka
Arundel Project and Geobiological Research




-----Original Message-----
From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] On Behalf Of
Sent: Thursday, July 21, 2011 22:18
To: dinosaur@usc.edu
Subject: Supernova link to Rancholabrean fauna extinction?

From: Ben Creisler

OK...this is not about dinosaurs, but it may interest people anyway. At
least it might inspire some paleoartists...

G. Robert Brakenridge (2011)
Core-collapse Supernovae and The Younger Dryas/Terminal Rancholabrean
Icarus (advance online publication)

Early predictions that some supernovae release large quantities of prompt
high energy photons are now corroborated by optical identification of
core-collapse supernovae associated with extragalactic GRBS (beamed
gamma-ray bursts) and XRFS (beamed or unbeamed x-ray flashes). Given the
in-galaxy supernova frequency and GRB and XRF recurrence statistics,
significant Earth-incident events during the past several million years very
likely occurred and nearby events should have affected the Earth and other
planetary atmospheres, including terrestrial surface solar UV, the Earth?s
climate, and its ecology. The Younger Dryas Stadial (12,900 to 11,550
calendar yr BP) began with sharply cooler temperatures in the Earth?s
northern hemisphere, regional drought, paleoecological evidence compatible
with increased UV, and abrupt increases in cosmogenic 14C and 10Be in ice
and marine cores and tree rings. In North America, stratigraphic and faunal
sequences indicate that a major pulse of mammalian extinctions (at least
23-31 genera) began very close to 12,830 calendar yr BP and was sudden:
deposits one century younger are devoid of diverse extinct fauna remains. A
10 second beamed GRB within 2 kpc of the Earth delivers 100 kJ m-2 fluence
to the Earth?s atmosphere, where it causes spallation and catalytic
reactions depleting 35-50% O3, and producing excess NOx species (which favor
cooling, drought, and surface fertility), 14C, and 10Be. An un-beamed, 1050
erg hard photon impulse at  250 pc produces similar terrestrial atmospheric
effects. A well-characterized massive star supernova, the unusually close
Vela event (d = 250 ± 30 pc; total energy of 1-2 x 1051 erg; age constrained
from remnant nebula shock velocities considerations at 13,000-16,000 yr and
from the pulsar characteristic age at 11,400 yr) may have initiated the
Younger Dryas climate change, and caused the extinction of the terminal
Rancholabrean fauna.

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