Jim
Justified & Ancient
- Joined
- Jan 19, 2016
- Messages
- 1,225
- Location
- NYS, USA
Sorry but you don't seem to have stabilized around a coherent topic, or maybe it’s me.Current thinking amongst geologists seems to be - one coffin, lots of nails.
I believe the impact explanation arose and remains the explanation in popular culture for a number of interesting reasons. First of all, we are in a period where very simple A B C explanations are the dominant norm. a) there was a big rock in space b) it hit the earth c) all dinosaurs plus mosasaurs, lots of species of shellfish, most of the Foraminifera etc died because of all the fire and dust and general terribleness*. On the other hand crocodiles, birds and mammals like it toasty warm, so they were OK.
Secondly there is the fall and rise of catastrophism in earth sciences. For over a hundred and fifty years geology was a science that rejected the notion of rapid large or planet wide changes. Enormous floods, immense upheavals, cities buried in brimstone were purely for the frankly overwrought and fictional Bible. Earthquakes and volcanic activity might be devastating, but these were localised events that could not level civilisations, never mind cause mass extinction. The 'standard model' was of an ancient planet v e r y slowly changing. To explain the landscape, text books described complex theories of basin spreading and the gentle rise or fall of the crust to form mountains and seas. Marie Stopes and Alfred Wegener’s ideas on continental drift were seen as, at best, on the fringe and at worse the musings of cranks. Even the work on ocean ridges undertaken by Columbia University in the late 50’s, which really began the modern study of plate tectonics was met with strong scepticism.
But by the early 70’s I believe two trends were converging. The threats of atomic war and large scale environmental destruction led to a sense of finitude and if not impending total annihilation then at least a dystopian near future. And in the fields of geology and astronomy the mass of evidence for the earth being a dynamic and changing system, often subject to extreme, violent and often brief events was becoming more accepted. The cosy ideas of the previous generation of geologists were replaced with super calderas, immense post glacial floods, tsunamis and a host of ever more extreme possibilities. And so currently we are always on the brink of featuring in our very own disaster movie, which gives a trip to Sainsburys a bit of an edge.
The discovery of impact debris all around the world at the KT boundary was a remarkable scientific achievement, and the correlation with the immense impact scar buried under Yucatan is I believe undisputed. Yet how this fits in with (to pick just a few things geologists have discussed since the early 80’s) volcanism in what would become India, a changing climate due to the widening Atlantic and the rapid changes in the evolution of the flowering plants is still being researched.
* You can put anything into that formula–ideas about social healthcare, social security systems, immigration, causes of criminal behaviour–lots of people really really do not like complexity. For example: a) The EU is dominated by Germany and France b) Lets be honest, historically the UK has had a hard time with those buggers c) Therefore the EU is just a bad thing. See Trump, Daily Mail et al
The URL’s from post 539 and 540 provide straightway data concerning a meaningful search for the demise of the Dinosaurs (and other flora and fauna) at the end of the Cretaceous period. The factors are numerous as the articles point out and since nobody was there they are doing their best with what they have.
I think with the new dating techniques and knowledge of weathering geology is at a pinnacle compared to years gone by.