EARTHQUAKE UPDATE
Yesterday's earthquake will not receive recognition in comparison to great earthquakes of the past, or even the present severe one in Nepal this past week. One five years ago in Haiti resulted in the death of over 316,000 people; the second largest (in fatalities), recorded after 800,000+ in 1556 in China, was followed by 300,000 in 1737 in Calcutta, India.
The geologically stable (relatively) state of Michigan had its worst earthquake in 1947, not far away, near Coldwater at 4.6 on the Richter scale, whereas the 4.2 or 4.4 of yesterday ranked second and was centered about five miles south of Galesburg, in Kalamazoo County near Scotts and Climax. For comparison the Haiti quake was 7.0 but the even larger quake of 2011 rated at 9.0 caused the death of over 20,000 due the large tsunami generated as a result of its offshore location in close proximity to Fukushimi, Japan.
THE CAUSE OF YESTERDAY'S QUAKE
Because it was centered over three miles deep, those quoted on TV and/or in the paper thought it was not related to the much shallower depth of wells involved in possible fracking activities there. It is along a fault line running from NW to SE through the area and many miles in each of those directions.
So it was thought to be due to two of the earth's crustal plates shifting or sliding over one another. It started me thinking about continental drift, plate tectonics, and their causes and effects. I mentioned glacial rebound (I should have said crustal rebound from the demise of the continental glaciers). Such rebound it evident from the high past shorelines of Lakes Michigan-Huron noted on Mackinac Island compared to other locations.
CONTINENTAL DRIFT
The movements of continents and the formation of the Atlantic Ocean are well accepted now. When I arrived in Tasmania in 1956, a international conference on Continental Drift had just been completed. They were telling me it was well accepted as a concept by all but the American geologists who thought there was no cause known to be strong enough to cause the movement. I had already thought the biogeographic evidence was so strong it had to be true. So I mused about how the earth was a little bit similar to a simmering pot of soup. The upwelling generated by the heat below produced a column that rose and spread carrying surface material aside.
Once the earth's surface cooled sufficiently and the crust was thick and lighter the accumulation may have caused a reversal of the circulation due its insulating effect and an new column arose under it to disperse the present continents and widen the Atlantic. The collisions following such movements and continued pressure produced by oceanic plates caused some of the subsequent mountain building and other events. The reduction of deep sources of heat due to decay of radioactive elements may have caused some decline in rates of crustal movement.
DOES THE MOON HAVE A ROLE?
When I looked at the paper and saw we will have a full moon tonight, I thought about the role of tides in the above movements. Could it have been the straw that broke the camel's back; were tides of sea and earth reaching a peak that triggered quakes. Probably not, but perhaps tides could be a factor in minor crustal movements that accumulate to cause quakes etc.
The tides move a tremendous amount of water and its attendant weight about with approximately a twice daily cycle that is of greater magnitude during a twice monthly cycle when sun, moon, and earth or sun, earth and moon are aligned. When the stresses produced by tides are aligned with crustal movement forces, the movements could show a twice daily cycle of speed or movement if measurements were able to record them. Then again, it may just be my imagination.
MICHIGAN'S GLACIAL GEOLOGY
I thought about Michigan geology. The Lower Peninsula of Michigan has subsurface geology resembling a stack of saucers. Devonian deposits outcrop around the rim and progressively younger deposits are at the surface as you go to the central part. Above the Devonian are layers that include salt, gypsum, coal, limestone, and sandstone of varying thickness. Bedrock is topped by glacial till containing predominately sand, gravel, and clay in an unconsolidated layer as much as 1,000 feet deep in some places. In many places the water of the melting glaciers left nearly horizontal layers varying according to the materials the melting glacier carried and the flow of the departing water.
Since the coral deposits and other marine material indicated it formed in a shallow sea, it occurred to me that perhaps the saucer like shape of the layers was due to glacial weight after the shallow sea sediments had been deposited. A likely candidate was late Permian glaciation near the end of the Paleozoic Era that was associated with the extinction of about 95% of marine and terrestrial species. It was long before the Atlantic Ocean became a significant body of water. Once the continental glacier, centered on or north of Michigan, got high enough, the altitude effect would prevent melting and perhaps produce a massive ice mountain deforming the flat sediments to its cup shape configuration.
When continental glaciation more recently happened (during Pleistocene glaciation), it is thought to have been centered farther north in Canada so the scouring effect increased the depth of the Great Lakes and caused the formation of the Finger Lakes in New York State.
Joseph G. Engemann May 3, 2015
Showing posts with label continental glaciers. Show all posts
Showing posts with label continental glaciers. Show all posts
Sunday, May 3, 2015
Saturday, February 14, 2015
SNOW STORM STIMULUS
"The weather outside is frightful"
Is the way an old song in a movie starts. Then it moves on to positive things about a relationship. Well, I just was doing somewhat the same after looking out the window. Snow was coming down in bursts to add to the already significant accumulation. But it was no where near the amount Boston had been experiencing. As long as power doesn't go out the gas furnace will run and keep us reasonably warm. As I lingered over coffee and my last piece of toast, I started musing about the value of a snow storm.
GLACIERS
They were an important part of the way God made the world where we live. The Great Lakes wouldn't exist if enormous glaciers of the not so distant ice ages had not carved them deeper by successive advances from what is now Canada. Where bed rock is visible the scratches of embedded rocks the glaciers picked up show how they did the job of gouging out the lakes efficiently.
The melting glaciers left a large quantity of the load of rocks and sand they were carrying to form a deep layer of glacial till deeply covering places such as southern Michigan. That till was layered in many places by the flow of melting water. So layers of rock, sand, and clay are able to provide an abundant source of ground water that is relatively pure until we pollute it by some of our activities.
Mountain glaciers still exist. Many are getting smaller or even disappearing. The annual snow fall can still replace much of the supply for summer melt to maintain streams and water resources of western states. But it is not as reliable. I understand "Grasshopper Glacier" in Glacier National Park has disappeared. It used to release locusts of no longer existing species, captured in its accumulation in the distant past, from the melting front of the glacier.
A woman working in an Austrian field while snow is still in the Alps
A small glacier on top of the Zugspitze, the tallest mountain in Germany
Although global warming is currently having a considerable affect on the Northern Hemisphere glaciers, those of Antarctica may still be growing or maintaining themselves. Once the continental glaciers of North America melted sufficiently, their elevation was not enough to keep snowfall and temperatures at levels to compensate for summer melting.
GROUND WATER
In Michigan, enough rain falls to replenish the ground water. The soil does a pretty good job of purifying the water of contaminants from simple agricultural and domestic activities. Deep well injection of wastes, fracking, and waste dumps improperly sited and sealed can drain into deep aquifers used for well water supplies without soil being able to effectively oxidize, filter, or somehow remove toxic wastes.
Aquifers can be enormous. One in the United States runs from some distance west of northern Illinois for hundreds of miles to the southwest. But heavy use of well water for irrigation has depleted its store of water at a rate exceeding replacement. A somewhat similar phenomenon is affecting oases in the northern Sahara. There, the lowered water table of the enormous store largely left during the ice ages has caused browning and death of some vegetation around the periphery of oases. And some wells show progressively deeper excavation to reach water.
SEASONS AND EVOLUTION
With or without global warming, the seasons will continue. Short term effects on an annual basis will favor selection for either or both, a north-south oriented seasonal migration, or adaptions for either cooler or warmer conditions. Long term effects are similar, but continuation of the same alternation can result in greater change in a species.
Lighter coloration and chunkier bodies are selected for in colder regions. Greater development of melanin pigment in the skin reduces U-V light penetration, thus the production of vitamin D in the skin is less likely to reach toxic levels in tropical climates. Distribution, types, and amounts of hair, fur, or feathers are simple evolutionary solutions for adapting to light and temperature of local conditions. Migration provides a substitution of behavioral change for physical change needed to adapt to climate.
Speed of climate change may be too great for annual migration or adaptation to prevent extinction. Will polar bears survive if summer ice is eliminated in the Arctic Ocean? I don't know. Did rapid warming reduce appropriate habitat for mastodons and mammoths, or did early human hunters eliminate them? I don't know. Perhaps it was both acting together.
Species can often adapt by migration over longer periods of time to new favorable locations unless too much desert, ocean, or mountain range, or intervening populations of predators, or other unfavorable habitat intervenes. It would have been hard for a mammoth to find a log to float on across the Gulf of Mexico. East-West migrations were successful in making Europe, Asia, and North America share very similar groups of species of plants and animals. A land bridge formed between Russia and Alaska was a major factor. Fresh water along the glacial front in that area probably enabled many genera of fresh-water fish that are now shared reach the opposite continent.
SUMMER THUNDER STORMS
Will I have to wait for confinement by another snow storm now or next year, or will a summer thunder storm that keeps me off the golf course provide an inspirational interlude?
Joe Engemann Kalamazoo, Michigan February 14, 2015
Is the way an old song in a movie starts. Then it moves on to positive things about a relationship. Well, I just was doing somewhat the same after looking out the window. Snow was coming down in bursts to add to the already significant accumulation. But it was no where near the amount Boston had been experiencing. As long as power doesn't go out the gas furnace will run and keep us reasonably warm. As I lingered over coffee and my last piece of toast, I started musing about the value of a snow storm.
GLACIERS
They were an important part of the way God made the world where we live. The Great Lakes wouldn't exist if enormous glaciers of the not so distant ice ages had not carved them deeper by successive advances from what is now Canada. Where bed rock is visible the scratches of embedded rocks the glaciers picked up show how they did the job of gouging out the lakes efficiently.
The melting glaciers left a large quantity of the load of rocks and sand they were carrying to form a deep layer of glacial till deeply covering places such as southern Michigan. That till was layered in many places by the flow of melting water. So layers of rock, sand, and clay are able to provide an abundant source of ground water that is relatively pure until we pollute it by some of our activities.
Mountain glaciers still exist. Many are getting smaller or even disappearing. The annual snow fall can still replace much of the supply for summer melt to maintain streams and water resources of western states. But it is not as reliable. I understand "Grasshopper Glacier" in Glacier National Park has disappeared. It used to release locusts of no longer existing species, captured in its accumulation in the distant past, from the melting front of the glacier.
A small glacier on top of the Zugspitze, the tallest mountain in Germany
Although global warming is currently having a considerable affect on the Northern Hemisphere glaciers, those of Antarctica may still be growing or maintaining themselves. Once the continental glaciers of North America melted sufficiently, their elevation was not enough to keep snowfall and temperatures at levels to compensate for summer melting.
GROUND WATER
In Michigan, enough rain falls to replenish the ground water. The soil does a pretty good job of purifying the water of contaminants from simple agricultural and domestic activities. Deep well injection of wastes, fracking, and waste dumps improperly sited and sealed can drain into deep aquifers used for well water supplies without soil being able to effectively oxidize, filter, or somehow remove toxic wastes.
Aquifers can be enormous. One in the United States runs from some distance west of northern Illinois for hundreds of miles to the southwest. But heavy use of well water for irrigation has depleted its store of water at a rate exceeding replacement. A somewhat similar phenomenon is affecting oases in the northern Sahara. There, the lowered water table of the enormous store largely left during the ice ages has caused browning and death of some vegetation around the periphery of oases. And some wells show progressively deeper excavation to reach water.
SEASONS AND EVOLUTION
With or without global warming, the seasons will continue. Short term effects on an annual basis will favor selection for either or both, a north-south oriented seasonal migration, or adaptions for either cooler or warmer conditions. Long term effects are similar, but continuation of the same alternation can result in greater change in a species.
Lighter coloration and chunkier bodies are selected for in colder regions. Greater development of melanin pigment in the skin reduces U-V light penetration, thus the production of vitamin D in the skin is less likely to reach toxic levels in tropical climates. Distribution, types, and amounts of hair, fur, or feathers are simple evolutionary solutions for adapting to light and temperature of local conditions. Migration provides a substitution of behavioral change for physical change needed to adapt to climate.
Speed of climate change may be too great for annual migration or adaptation to prevent extinction. Will polar bears survive if summer ice is eliminated in the Arctic Ocean? I don't know. Did rapid warming reduce appropriate habitat for mastodons and mammoths, or did early human hunters eliminate them? I don't know. Perhaps it was both acting together.
Species can often adapt by migration over longer periods of time to new favorable locations unless too much desert, ocean, or mountain range, or intervening populations of predators, or other unfavorable habitat intervenes. It would have been hard for a mammoth to find a log to float on across the Gulf of Mexico. East-West migrations were successful in making Europe, Asia, and North America share very similar groups of species of plants and animals. A land bridge formed between Russia and Alaska was a major factor. Fresh water along the glacial front in that area probably enabled many genera of fresh-water fish that are now shared reach the opposite continent.
SUMMER THUNDER STORMS
Will I have to wait for confinement by another snow storm now or next year, or will a summer thunder storm that keeps me off the golf course provide an inspirational interlude?
Joe Engemann Kalamazoo, Michigan February 14, 2015
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