Geology news

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.

Alaskan Muck Deposits

What has been found in the Muck deposits rather than what caused the muck deposits. See for example https://mostlymammoths.wordpress.com/tag/alaska/ ... in 2004 scientists in the Yukon discovered a surprising remnant of the Pleistocene, an Ice Age flower meadow (including some of the grasses which were still green but dating back 30,000 years ago). It was situated below a layer of tephra at Gold Bottom Creek, some 40m long (and buried and preserved by the volcanic ash). It is therefore an invaluable source of information about conditions in the Yukon during the Late Pleistocene.

Ichniotheriums

William sent in this link - https://phys.org/news/2019-05-newly-fossil-footprints-paleontologists-re... ... newly discovered fossil footprints force paleontologists to rethink ancient desert inhabitants. The footprints were discovered in a remote part of the Grand Canyon National Park - see for instance www.sciencedaily.com/releases/2018/11/181108142448.htm ... and https://www.nps.gov/grca/learn/news/newly-discovered-fossils.htm ...

Trapped in Amber

Another imponderable. Lots of things get trapped in amber but most are land mased animals and insects - or freshwater (from a wetland environment). One can think of dragonflies for example. Now, a Chinese researcher has found the first known ammonite trapped in amber - and ammonites are deep sea animals. It came from the Myanmar amber bed (in Burma). These amber beds also include sea snails and sea slaters ... all marine species. At https://archaeologynewsnetwork.blogspot.com/2019/05/coastal-organisms-tr... ...

Gulf of Mexico Geology

At https://phys.org/news/2019-05-complex-geology-contributed-deepwater-hori... ...  a research paper in Scientific Reports (May 7th 2019) says that complex geology in the Gulf of Mexico contributed to the Deepwater Horizin disaster. Most commentators have, to date, concentrated on the engineering decisions that led to the bow out or the ecological consequences of the oil spill.