THEY DON'T MAKE CATASTROPHES LIKE THEY USED TO

It's only a matter of time before the usual climate loons hijack Mike Rampino's latest paper, but bravo to him anyway for his December Monthly Notices of the Royal Astronomical Society paper  announcing something refreshingly new under the sun 

Forget Nemesis encounters doing in the dinosaurs--Mike doesn't do existential threat inflation by halves.

Instead, try gross ( hundreds of Kelvins ) heating of the Earth's entire core by sporadic infall and annihilation of clumps of  WIMP dark matter  as the solar system traverses the galactic plane.  Mike hypothesizes that the big delta T could drive accelerated tectonics and rifting, leading to or exacerbating extinction events  large and small:

Wheras  ordinary  solar system  dark matter flux annihilation is estimated, assuming  ta ab=∼0.34, ρ 0.3=1, V300 =1, mX =15–100 GeV and the cross section of iron  σN  to be ~10 to the minus  32 cm2, to warm earth's core by only four ten thousandths of the current geothermal flux, (Mack, Beacom & Bertone 2007).

Rampino reckons that 

For encounters with dense clumps of DM, however, with coreDM densities up to 10^9 times the average (Silk & Stebbins 1993)...up to 10^19 W of internal heating is possible during clump crossing, with clumps encountered every ∼30–100 Myr (Collar 1996)

here's the abstract :

Disc dark matter in the Galaxy and potential cycles of extraterrestrial impacts, mass extinctions and geological events

1. Michael R. Rampino¹,²,³,^★

1. ¹Department of Biology, New York University, New York, NY 10003, USA
2. ²Department of Environmental Studies, New York University, New York, NY 10003, USA
3. ³NASA, Goddard Institute for Space Studies, 2880 Broadway, New York, 

• Accepted 2014 December 30. Received In original form 2014 November 4.published online February 18, 2015.

Abstract

A cycle in the range of 26–30 Myr has been reported in mass extinctions, and terrestrial impact cratering may exhibit a similar cycle of 31 ± 5 Myr. These cycles have been attributed to the Sun's vertical oscillations through the Galactic disc, estimated to take from ∼30 to 42 Myr between Galactic plane crossings. Near the Galactic mid-plane, the Solar system's Oort Cloud comets could be perturbed by Galactic tidal forces, and possibly a thin dark matter (DM) disc, which might produce periodic comet showers and extinctions on the Earth. Passage of the Earth through especially dense clumps of DM, composed of Weakly Interacting Massive Particles (WIMPs) in the Galactic plane, could also lead to heating in the core of the planet through capture and subsequent annihilation of DM particles. This new source of periodic heating in the Earth's interior might explain a similar ∼30 Myr periodicity observed in terrestrial geologic activity, which may also be involved in extinctions. These results suggest that cycles of geological and biological evolution on the Earth may be partly controlled by the rhythms of Galactic dynamics.