Tuesday, June 28, 2022

Links: Long Covid, Galapagos Islands, Origin Of Life

 I enjoyed reading these over the past few days.

1) Clues to Long Covid:  The disease that has affected us over two long years is still quite a mystery. Jennifer Couzin-Frankel has written a very informative article on the quest to understand Long Covid and how to treat it. 

2) The Galapagos Is a Glimpse of Eternity.  Geology influence organismal habitat and life habits. Penguins nesting in lava tubes. Tortoises finding warm volcanic vents to raise their body temperatures. Paul Stewart describes the landscapes of the Galapagos Islands with its amazing biodiversity, now threatened by climate change. 

3) From Pre Biotic Soup To Fine Grained RNA World. I often come across new articles breathlessly announcing that organic molecules of various types have been found on asteroids. But whatever the source of different molecules, it is specific conditions on early earth that we need to understand to arrive at a sensible theory of the origin of life. Fine article by Philip Ball.

Friday, June 17, 2022

That Day 66 Million Years Ago

Just wanted to share this abstract of a paper detailing an outcrop from Baja California, Mexico, which preserves heterogeneous deposits resulting from the Chicxulub meteorite impact 66 million years ago. 

We report K-Pg-age deposits in Baja California, Mexico, consisting of terrestrial and shallow marine materials re-sedimented onto the continental slope, including corals, gastropods, bivalves, shocked quartz grains, an andesitic tuff with a SHRIMP U-Pb age (66.12 ± 0.65 Ma) indistinguishable from that of the K-Pg boundary, and charred tree trunks. The overlying mudstones show an iridium anomaly, and fungal and fern spores spikes. We interpret these heterogeneous deposits as a direct result of the Chicxulub impact, and a mega-tsunami in response to seismically-induced landsliding. The tsunami backwash carried the megaflora offshore in high-density flows, remobilizing shallow marine fauna and sediment en route. Charring of the trees at temperatures up to >1000°C took place in the interval between impact and arrival of the tsunami, which on the basis of seismic velocities and historic analogues amounted to only tens of minutes at most. This constrains the timing and causes of fires, and the minimum distance from the impact site over which fires may be ignited.

Raging forest fires, a tsunami and its backwash, hundreds of millions of tons of sediment mobilized as gigantic mixed debris flows, ecosystems laid waste.

What a catastrophic time! 

The paper is open access but be aware that it is a preprint, yet to be peer reviewed. 

Forest fire at the K-Pg boundary on the Pacific margin of Baja California, Mexico: timing and causes- Amanada Santa Catharina et.al. 2022.