It appears the age old argument between geologist as to the age of the Grand Canyon is getting even hotter these days. It revolves around how fast can a fast flowing river such as the Colorado River actually cut down through the rocks. Sections of the canyon have been cut though at more recent times. Anyway, its fun to consider. I will find more detailed articles to provide more background.
Post by oldpop2000 on Feb 22, 2014 22:46:10 GMT -5
I was reading "Letters from Pliny the Elder" this evening. Pliny was the first volcanologist and was living in Naples at the time of the eruption of Vesuvius in 79 AD. Now in this eruption, Naples was not damaged but Pompeii and Herculaneum were buried. This is the first detailed account of an eruption ever written. The letters were written to Tacitus his friend.
Vesuvius rises about 4000 feet above Pompeii and Naples. Pliny states that there were frequent earthquakes and both cities were damaged sixteen years earlier by a very strong series of earthquakes. He states that no one suspected the existence of the volcano. This is interesting because we have found a very thick layer of pumice and ash underneath Naples dating back to an eruption about 1700 BC. No written record was ever found. The Great Eruption of Vesuvius is described in Chapter II. Pliny writes that it started at one o'clock in the afternoon on the 24th of August. He describes the initial stages like this
A cloud of unusual size and shape, which was visible on the opposite side of the Bay- It rose from one of the hills, which the observers did not know at the time to be Vesuvius, like a stone-pine with a lofty trunk and a cluster of branches at the top, continually varying in height, and of a changing hue, sometimes fiery bright, sometimes streaked with black.
Note: The eruption described is now given the name "plinian eruption".
Pliny writes that his uncle, admiral of the fleet in Naples ordered a galley to set sail and asked the younger nephew to join him but he declined. The younger states that the two never met again. Once on the shore, the elder realised the danger to the people and ordered the fleet to set sail to the opposite side of the bay at the point of danger. The younger writes that showers of cinders and fragments of heated stone began to fall around the ships. The "soundings of the Bay were altered". He attributed this to the rising sea bed. The fleet made for Stabise, near the extreme southern point of the bay. The fleet began to embark the people and the elder Pliny went to a villa nearby of a friend. Flames were beginning flow out of Vesuvius, but the elder went to sleep, however the courtyard filled with ash and stone making exiting the house impossible. The elder died in that villa probably of sulfurous asphyxiation.
The younger continues with the narration stating that finally at 7:00 o'clock in the morning he and his mother departed the town because of the danger. He describes the falling cloud of ash, descending upon the earth covering the sea. Eventually, the younger states that the light came back as the ash clouds began to subside.
We now know that Herculaneum was buried by a pyroclastic flow of volcanic mud, moving at about 450 MPH with a temperature of about 900 degrees, hot enough to melt gold. We have recently discover bones of people in boat docks, whose bones were burned. This only occurs at about 900 degrees. Pompeii was buried by a thick layer of ash and stone. Pliny the Younger actually wrote the letter describing what happened on that day and the fate of his uncle, Pliny the Elder.
Last Edit: Feb 22, 2014 22:46:31 GMT -5 by oldpop2000
Post by oldpop2000 on Feb 25, 2014 16:54:19 GMT -5
Global Warming and Volcanoes
We know through ice cores that the world climate has had periods of warming and cooling. In fact, we have a theory, based on those cores that states that the earth was once covered with ice. It even reached the equator. The phenomenon is called "snowball earth". We know through our own human record that there was a "year without summer" in 1816 due to the eruption in Indonesia of Mount Tambora. It partially occurred in 1883 due to Krakatoa. All in all, via human records, geologic records etc. we know that large eruptions of volcanoes can modify the earths climate specifically decreasing the temperature around the world.
I've mentioned this because a new study, states that "the unusual swarm of volcanic eruptions over the last 14 years may be partially responsible for the slowing of global warming. " There have been 17 eruptions from 1998-2012 which pumped sulfur dioxide into the earth, blocking the sunlight and thereby cooling the earth.
Really.....!! You mean someone finally realized what volcanologist knew a long time ago, that volcanism can modify the earth's climate. That some of our heating is due to the fact that we are midway through an interglacial warming period. That the oceans can and do remove heat from the lower troposphere and spread it around the globe in the Atlantic Conveyor. It's almost like the media, politicians and the scientists are on different wavelengths and can't communicate. Maybe they should talk more. Wonderful.
Last Edit: Feb 25, 2014 16:55:45 GMT -5 by oldpop2000
Native Americans spent 10000 years in Bering Strait, a 1000 X 3000 mile area
Scientist have long known that the native Americans came from the NE area of Siberia and that they arrived here on the Bering Strait land bridge, given the cute title of Beringia. New cores say that its possible that Beringia was not just tundra but was spotted with areas of shrubs, and trees. The temperatures in the area might have been mild and that the native Americans could have stayed on that land bridge for 10,000 years in teepees and other types of homes. Now, this is just an hypothesis designed to account for the genetic data from the Indians and the ice cores, so don't hold your breath. But still, 10,000 years in that northerly area? Man I would have moved out of there as fast as I could and headed south.
La Habra Earthquake and Puente Hills Blind Thrust Fault Zone
As you should know, there was a 5.1 magnitude earthquake centered around La Habra California, which is close to downtown Los Angeles. It was about 7.5 KM down which is shallow. It was originally thought to have originated on the Whittier section of the Elsinore Fault Zone which runs northwest along the Chino Hills north of La Brea, Whittier etc. It is now believed that the earthquake and the subsequent hundreds of aftershocks, some as large as 4.1 originated on the Puente Hills blind thrust fault. This new fault zone was discovered in 1999 by a team from Harvard and runs from northern Orange county directly under downtown LA. The term "blind" simply means that it does not appear on the surface so it is difficult to study. As a thrust fault it produces folds as opposed most California faults which are strike slip, simply meaning that the rocks on both sides are sliding by each other, and developing stress and strain. This new zone could produce an earthquake as high as 7.5 and that is higher than the Northridge quake. The new zone has broke four times in 11,000 years. This maybe a seismic lull period, and it could be over. BTW, we felt the 5.1 in San Diego as a brief rolling, but nothing more.
Last Edit: Apr 1, 2014 12:12:06 GMT -5 by oldpop2000
As you might have heard, there was an 8.2 quake on the Peru-Chile Trench. This earthquake is the result of the movement of the Nasca Plate heading ENE at 79 mm/yr. on average; it moves at 80mm/yr. in the south. subducting the South American plate. These subduction zones tend to generate the largest earthquakes and corresponding largest tsunami's when occurring under the ocean. There have been numerous aftershocks, some as high as 6.2 most averaging around 4.8-5.0.Those are still dangerous especially to structures along the coast that were already damaged by the 8.2. Luckily, the earthquake was over 20 km down. The largest instrumentally recorded earthquake in history occurred in this same region in 1960. it was recorded as a 9.5 on the Richter scale. Just for comparison, the 5.2 in La Habra was over 100,000 times weaker than this 9.5 earthquake.
Last Edit: Apr 1, 2014 23:39:36 GMT -5 by oldpop2000
For those of you who are remotely interested in more knowledge than CNN provides on the 8.2 Earthquake off of SA, here is a nice piece by the USGS. It does touch on the Nazca Plate which was one of plates that generated the earthquake.
There have been some significant aftershocks from the 8.2 subduction zone earthquake of April 1st. One of them was a 7.6 off of the west coast of Northern Chile. This fracture zone extends over 7000 km according to the USGS and intersects with the Panama fracture zone offshore of Central Panama. There was a 6.0 earthquake on that Panama fracture zone yesterday. I wonder if the movements off of Chile have increased the strain and hence this 6.0 was caused by that movement. This region is the boundary between four plates; North America, South America, Nazca and Cocos and borders the Caribbean plate. Although USGS hasn't mentioned it yet, the two earthquakes and subsequent aftershocks could be interrelated.
Post by oldpop2000 on Apr 18, 2014 19:11:10 GMT -5
We've all heard the story of how Greenland got its name. Leif Erikson gave it that name to lure Icelanders to populate it. That worked for a while, but seriously, if we look at it, it really doesn't look that it was ever green. Well here is an article that states that scientist have found the remnants of tundra and that Greenland was actually green once.
Post by oldpop2000 on May 16, 2014 13:10:41 GMT -5
Here is an interesting bit of archeology. As you should know, there was a land bridge, Beringia, about 13,000 years ago and that Clovis people moved across that bridge, over time, down the Canadian coast into North America. This would mean that the native Americans have Asian backgrounds in their history. This has been called the Bering Strait Theory first proposed in 1590 b Jose de Acosta. The way to prove the theory was to do DNA samplings looking genomes relating to the inhabitants of southern Siberia from the Altai Mountains in the west to the Amur River in the east.
It appears that a discovery in the Yucatan, in an underwater cave of a teenage girl who fell into the cave, has proven to have genomes from Asia. Her skull is narrower and taller than modern Native Americans. This proves that Paleo-Americans, the first Americans from which modern native Americans were descended from, were from a single migration out of Asian in the Americas. Evidence shows that the migration of ancient peoples actually stopped and lived on that land bridge.
This is a start but more DNA has to be found and classified but it does provide a missing link.
Post by oldpop2000 on Sept 11, 2014 8:54:56 GMT -5
Apparently searchers in Northern Canadian waters have found one of the two Franklin Expedition ships. news.yahoo.com/lost-ship-ill-fated-arctic-quest-discovered-183015062.html. Interesting that it was exactly where the Inuit's said it was located. There is another link embedded in the article which leads to another article about one of the ill-fated crew members whose remains were found some years earlier. It provides some background if you don't know the story of the Franklin Expedition.