April | 2022 | Barbara Roberts

Monthly Archives: April 2022

22919 Days Old

Another victim of the Toarcian anoxic event?

22917 Days Old

Ammonites in grey shale. Toarcian anoxic event victims?

22903 Days Old

Death assemblage drawing in progress. The future in retrospect.

Sample of The Beacon Beds collected in Ilminster, Somerset. The Beacon Limestone Formation is considered to index a global marine anoxia event. A more extensive explanation of the Beacon Beds is given in Geoscientist May 2020. As a condensed sequence in a non-reductive lithology I’m unsure about how it relates to the anoxia.

The occurrence of anoxic event(s) seems to be beyond dispute and there seem to be quite a few parallels between then and now. The Toarcian anoxic event(s) marking a tipping point in the Earth system is compared with current day ocean anoxia that is driven by anthropogenic release of greenhouse gases. “Effect of a Jurassic oceanic anoxic event on belemnite ecology and evolution”. (2013) Ullmann, Thibault, Hesselbro & Korte

Slightly worrying to put it mildly!

22899 Days Old

Otherlands – A World in the Making by Thomas Halliday. An interesting read envisioning different parts of the world at different times in the geological past. The epilogue is rather chilling with Halliday predicting another mass extinction unless we radically change our ways and reduce our huge overconsumption.

On a less doom laden note, who knew that the star Polaris only started shining in the Cretaceous? Seven of the stars in Orion are no older than the Miocene and Sirius dates from the Triassic. Watch and wonder.