Geology news

Plate Tectonics

An interesting post at https://phys.org/news/2019-09-plate-tectonics.html .... where we are presented with a little history of the Plate Tectonics theory. It only goes back to the late 1960s and is therefore a relatively new idea to expalin certain geological features. It assumes the distribution and movement of plates, the uppermost layer of the Earth, is a fact of life - yet it doesn't seem to happen anywhere else in the solar system. Only on the Earth. Are we unique - our geology that is. Can we get our heads around it - truth or fiction ...

Ice Age Savannah

One of the paradoxes of the last Ice Age is the existence of a savannah corridor that allowed animals and humans to spread into SE Asia. The region is now largely tropical in nature but back in the day a savannah environment stretched right across what is now the Malay peninsular, Thailand and Burma, into what was then Sunda Land - or what is now the islands of Indonesia. One complete block of land. The dates concerned are between 120,000 and 70,000 years ago  and explains how humans genetically linked to Denisovans ended up in the region.

Ice cores and volcanoes

An interesting and informative study that explains how ice cores have a volcanic signature and how it is possible to pinpoint specific eruptions - go to https://archaeologynewsnetwork.blogspot.com/2019/08/synchronization-of-i... ... during a volcanic eruption, gases, lava, rocks and tiny ash particles are ejected into the atmosphere. The smallest particles are carried by the wind and transported for miles until they drop out on to the surface of the earth - including over the ice sheet on Greenland.

magnetic flips

Gary sent in a cluster of links. For example, at www.space.com/lava-flows-earth-magnetic-field-reversal.html ... which concerns magnetic pole flips and associated volcanism. We are informed the process was much slower then previously envisaged. To arrive at this conclusion they used data from fossil lava flows.

The day the sea invaded the Sahara

At https://phys.org/news/2019-07-ancient-saharan-seaway-earth-climate.html ... in the Bulletin of the American Museum of Natural History (summer of 2019) we have a paper based on an accumulation of 20 years of research in what is now the Sahara desert. It is set between 100 and 50 million years ago = the Late Cretaceous and the early Paleogene (on the geological ladder). It concerns what is described as a sea way and the blame is placed squarely on rising sea levels.

Salty Ice Age

You learn something new everyday. A sediment core from the Maldives is said to have preserved ocean water from the last Ice Age. How do they know? It is more salty than modern ocean water - go to https://phys.org/news/2019-05-scientists-ancient-seawater-ice-age.html ... The thinking is that during the Ice Ages lots of water was locked up in glaciers and ice sheets. Therefore there was less water in the oceans as it is known sea levels in the North Atlantic were much lower during the Late Glacial Maximum. Less water means the salt in sea water is not spread around as much = salty sea water.

Off shore lake

Continental shelf systems are areas formerly above sea level but now submerged. Such regions may have been periodically submerged with variations in sea levels over geological time. However, the continental shelf system off the US North East has come up with a big surprise - it harbours a lake underneath the sea bed - go to https://tallbloke.wordpress.com/2019/06/23/scientists-map-huge-undersea-... ... the lake is actually very deep down below the sea bed and is described as an aquifer (a source of water from an ancient era).

Subduction and Diamonds

At https://archaeologynewsnetwork.blogspot.com/2019/06/researchers-simulate... ... researchers simulate the extreme pressure and heat in the earth's Mantle - or what they assume is the extreme pressure exerted by the Mantle. This is not simulation via computer make believe as they seem to have conducted a genuine experiment - simulating the subduction process and the manufacture of diamonds. I may be wrong but that is how the press release reads - or my interpretation of what they are saying.

Island Arc Earthquakes

At https://phys.org/news/2019-06-earthquake-swarms-reveal-piece-tectonic.html .... earthquake swarms are said to reveal mssing piece of tectonic plate volcano puzzle. Deep under the ocean, we are told, a sinking tectonic plate causes a swarm of earthquakes feeding molten lava into newly forming volcanoes. Researchers say they have found two swarms of earthquakes when researching the Mariana and Izo Bomin arc system in the Pacific Ocean.

Large Boulders Shape Canyons

At https://phys.org/news/2019-06-large-boulders-huge-canyons.html ... river valleys in hilly or mountainous country have the remnants of water surges in them, discarded rocks of various shape and size. In the UK these can be seen even in small streams. A good example might be the river bed between Lynton (up high) and Lynmouth (down below), just a short distance but jammed with rocks and boulders. Some of these originate from a storm surge in 1953 when the lower town was flooded by a swollen river Lyn.