Caribbean geology

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Caribbean geology

Postby chiggerbit » Thu Jan 14, 2010 5:46 pm

Geology has always interested me, so i've been digging around, looking up Caribbean geology since the Haiti quake. Check out this trench, the Puerto Rico Trench, near Haiti, which is the deepest point in the Atlantic Ocean.

Image
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Re: Caribbean geology

Postby chiggerbit » Thu Jan 14, 2010 5:58 pm

Image

Description English: Perspective view of the sea floor of the Atlantic Ocean and the Caribbean Sea. The Lesser Antilles are on the lower left side of the view and Florida is on the upper right. The purple sea floor at the center of the view is the Puerto Rico trench, the deepest part of the Atlantic Ocean and the Caribbean Sea.
Date
2005-02-24 (original upload date)
Source
http://woodshole.er.usgs.gov/project-pa ... Large.html, originally from en.wikipedia; description page is/was here.
Author
Original uploader was Vsmith at en.wikipedia
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Re: Caribbean geology

Postby chiggerbit » Thu Jan 14, 2010 6:06 pm

Ironically, wiki says with regards to Puerto Rico, not Haiti:

http://en.wikipedia.org/wiki/Puerto_Rico_Trench

....Public awareness

Knowledge of the earthquake and tsunami risks has not been widespread among the general public of the islands located near the trench.

Since 1988, the Puerto Rican Seismic Society has been trying to use the Puerto Rican media to inform people about a future earthquake that could result in a catastrophic tragedy....
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Re: Caribbean geology

Postby chiggerbit » Thu Jan 14, 2010 6:19 pm

Damn, the Bermuda Triangle, it begins to look like:


http://pubs.usgs.gov/fs/fs141-00/fs141-00.pdf
...North of Puerto Rico is the Puerto
Rico Trench, the deepest part of the
Atlantic Ocean and the place where the
pull of gravity at sea level is less than
anywhere else on Earth
(free-air gravity
anomaly)....
Last edited by chiggerbit on Fri Jan 15, 2010 4:35 pm, edited 1 time in total.
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Re: Caribbean geology

Postby chiggerbit » Thu Jan 14, 2010 6:36 pm

Whew, we're talking some really complicated geology, plate movements, etc.

http://pubs.usgs.gov/fs/fs141-00/fs141-00.pdf

...Plate Movements
The Caribbean is one of the smaller
surface plates of the Earth. The approximately
rectangular plate extends from
Central America on the west to the Lesser
Antilles on the east, and from just south
of Cuba on the north to South America
on the south (fig. 1). Earthquakes occur
all around its periphery, and volcanoes
erupt on its eastern and western sides.
This plate remains at a fixed spot relative
to the deep Earth, while the North American
plate, which includes the continent of
North America and the western North
Atlantic ocean basin, is being shoved
westward.
The motion between these
plates is rapid for a geological process,
at about 2 centimeters/year (about
1 inch/year).

The Puerto Rico/Virgin Islands
region is located at the northeastern corner
of the Caribbean plate where motions
are complex. The westward-moving
North American plate is being driven
under the Antilles Arc where volcanism is
active. On the north side of the plate corner,
the North American plate slides past
the Caribbean (fig. 1), but irregularities in
the plate boundaries cause stresses that
result in a complicated underthrusting of
plate fragments.
The interaction of plates
causes the volcanism of the Antilles Arc
on the eastern boundary of the Caribbean
plate and creates major stresses all along
the northern boundary.

North of Puerto Rico is the Puerto
Rico Trench, the deepest part of the
Atlantic Ocean and the place where the
pull of gravity at sea level is less than
anywhere else on Earth (free-air gravity
anomaly). The stresses are holding part
of the North American plate down to
form the trench. The collision has also
caused the tilting of the limestone platform
deposits of northern Puerto Rico
during the last 3.3 million years.
These
formerly horizontal layers, deposited near
the water surface, now are tilted strongly
to the north and have subsided to depths
of more than 4.5 kilometers (2.8 miles).
Sea-floor images collected by the U.S.
Geological Survey (USGS) show that
great slabs of limestone, as much as 70
kilometers (43 miles) wide, have broken
off and slid into the Puerto Rico Trench.


Earthquake Patterns
Stresses in the plates cause frequent
earthquakes, and so the pattern of deep
earthquakes can be used to map the
locations of cold, brittle underthrust
plates (fig. 2). Two groups of earthquake
foci (locations of initial ruptures
within the Earth) extend diagonally
under the islands, one from the north
and one from the south. Apparently the
North American plate is bent down to
the south, and the Caribbean plate is
bent down to the north; they may be in
contact beneath the islands. The islands
are situated on a set of independent
small plate fragments or microplates

that are located in the V-shaped trough
between the downbent parts of the
major plates (fig. 3).

Large earthquakes have occurred
in the Puerto Rican region (table 1).
USGS research indicates an equal
probability for damaging ground
motion for Mayaguez in western
Puerto Rico as for Seattle, Washington;
other Puerto Rican cities also have
substantial risk.
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Re: Caribbean geology

Postby chiggerbit » Thu Jan 14, 2010 6:46 pm

I thought all those pimples in the Caribbean were formed by volcanoes. Cayman Islands this time:

http://www.emporia.edu/earthsci/student ... ml#Geology

...The Cayman Islands are the outcrops of the submarine mountain range associated with the Cayman Ridge. The Cayman Ridge has formed over geologic time due to the interaction between the North American and Caribbean tectonic plates. This submarine mountain range stretches from the Sierra Maestra mountain range of Cuba to the Gulf of Honduras and the Misteriosa Bank near Belize. The Cayman Ridge forms the northern margin of the Cayman Trough, which is around 250 kilometers wide and reaches depths in excess of 5,000 meters. The position of the Cayman Islands near the Oriente Transform fault and the mid-Cayman rise of the Cayman Ridge reveals that these three islands are individually uplifted fault blocks that were forced upward due to the frictional forces on the North American/Caribbean tectonic plate margin....
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Re: Caribbean geology

Postby chiggerbit » Sun Jan 17, 2010 11:51 am

http://rawstory.com/2010/01/scientists- ... ul-quakes/

Scientists: Haiti facing even more powerful quakes in the future

By Agence France-Presse
Saturday, January 16th, 2010 -- 4:15 pm
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Haiti and its neighbors must prepare themselves for more massive quakes after the devastating tremors this week increased pressure along a lengthy fault line, scientists warned Friday.

Paul Mann, a senior research scientist at the Institute for Geophysics at the University of Texas at Austin, warned that just because the rebuilding process had started people shouldn't assume the risk was over.

"This relief of stress along this area near Port-au-Prince may have actually increased stress in the adjacent segments on the fault," he told AFP.

Researchers have already begun to work on models to try to predict how the stress changes resulting from the 7.0-magnitude quake which struck Tuesday is affecting the adjacent segments of the fault.

"This fault system is hundreds of kilometers long and the segment that ruptured to form this ear quake is only 80 kilometers long," Mann said in a telephone interview.
Story continues below...


"There are many more segments which are building up strain where there haven't been earthquakes for hundreds of years.

"Potentially any one of these segments could cause an earthquake similar to that which happened in Haiti."

There are, thankfully, only two major population centers along the fault: Port-au-Prince and Kingston, Jamaica.

But as demonstrated in the chaos which followed Tuesday's tremor, the impact of a quake of that magnitude can be "paralyzing," Mann said.

Adding to the danger is the fact that the segment which broke was not among those closest to Port-au-Prince.

And there is a second fault system in the north of Haiti which extends to the Dominican Republic which has not ruptured in 800 years and has built up sufficient pressure for a 7.5 magnitude quake.

"The question is when are those going to rupture," Mann said, adding that it is very difficult to predict "whether or not that's going to happen next week or 100 years."

Eric Calais, a French geophysicist who works at Purdue University in Indiana, is among those trying to assess the danger.

He had warned Haitian officials years ago of dangerous pressure in the fault which caused this week's devastating quake, but little could be done to reinforce the desperately poor nation's weak buildings.

"The Haitian government is not to blame in this," Calais told AFP.

"They listened to us carefully and they knew what the hazard was. They were very concerned about it and they were taking steps. But it just happened too early."

Calais began researching the fault line in 2003 and soon took his initial findings to the Haitian government, even meeting with the prime minister.

In March 2008 he and Mann presented a paper showing that the fault had built up sufficient pressure to cause a 7.2 magnitude quake.

But they could not pinpoint when the quake might strike and the government was occupied with recovering from a series of four hurricanes which struck that year.

While the government had begun work on an emergency response plan, little could be done to retrofit and strengthen key buildings such as hospitals, schools and government buildings from which rescue operations could be organized.

"It's a poor country," Calais said. "Strengthening a building to resist a large earthquake can be as costly as replacing the building."

The devastation will allow Haiti to rebuild stronger than before, Calais said, noting that there are relatively cheap engineering solutions that can be applied to ensure that new buildings will not collapse in the next quake.

"It's very important for Port-au-Prince to rebuild properly," he added. "There are other segments of that fault that could rupture in the future."
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Re: Caribbean geology

Postby chiggerbit » Sun Jan 17, 2010 12:26 pm

Let me know if this map spread the thread for you. Oh, cool , it came out as a thumbnail. Click on it to get a closer look at all the islands.

Damn, good job et! These things used to come out too big. This is great.
Last edited by chiggerbit on Sun Jan 17, 2010 2:53 pm, edited 1 time in total.
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Re: Caribbean geology

Postby chiggerbit » Sun Jan 17, 2010 2:53 pm

Wait a minute, what happened? It showed as a thumbnail when I viewed it, and now it's too big. Now I have to delete it.
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Re: Caribbean geology

Postby chiggerbit » Sun Jan 17, 2010 2:59 pm

This one isn't as good, but it'll have to do, till I find a better one:

Image
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Re: Caribbean geology

Postby chiggerbit » Sun Jan 17, 2010 3:02 pm

Btw, did I mention my suspicion that there's oil down there in the Caribbean?
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Re: Caribbean geology

Postby chiggerbit » Sun Jan 17, 2010 3:07 pm

Image

http://www.ig.utexas.edu/research/proje ... .links.htm

"....All findings and data published in Proceedings of the Ocean Drilling Program volumes from the Ocean Drilling Program are now available in digital format at http://www.odplegacy.org (click on Samples, data & publications). The second phase of the digitization project, to be completed by this fall, will bring the Initial Reports of the Deep Sea Drilling Project series (Volumes 1-96) and other printed ODP and Deep Sea Drilling Project (DSDP) reports online. The DSDP publications will be available at http://www.deepseadrilling.org.
News release...."
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Re: Caribbean geology

Postby seemslikeadream » Sun Jan 17, 2010 3:25 pm

excellent chiggerbit, thanks for posting this

Image
Mazars and Deutsche Bank could have ended this nightmare before it started.
They could still get him out of office.
But instead, they want mass death.
Don’t forget that.
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Re: Caribbean geology

Postby chiggerbit » Sun Jan 17, 2010 4:11 pm

Thanks, slad!

Well, I'll be darned, there's already a bit of oil and gas production in the Caribbean. Of course, if there's a bit, there's the likelihood of a whole lot more.

http://geology.com/energy/caribbean/

Caribbean Energy: Oil and Natural Gas
Republished from a report by the Energy Information Administration
Background

The islands of the Caribbean basin are predominantly net energy importers, with the exception of Trinidad and Tobago. Some islands, such as Aruba, Curacao, and the U.S. Virgin Islands, are important centers for oil refining and storage, due to their proximity to the U.S. market. In recent years, there has been concern that higher global oil prices will impair the Caribbean economies, as they are highly dependent upon oil for the energy needs. In response, the island nations have been discussing ways to promote alternative energy sources and better integrate their energy sectors.


Oil Production

Trinidad and Tobago:
Trinidad and Tobago contains the majority of the Caribbean's oil production. In 2008, the country produced 165,420 barrels per day (bbl/d) of total oil production, of which 114,280 bbl/d was crude oil, the remainder mostly consisting of natural gas liquids (NGLs). In 2008, Trinidad and Tobago consumed an estimated 41,000 bbl/d of oil, allowing it to export a sizable amount of its production. The largest oil producer in the country is the state-owned Petroleum Company of Trinidad and Tobago (Petrotrin). Other large producers include BP Trinidad and Tobago and BHP Billiton.



America's New Oil Source
The Next Huge U.S. Oil Boom is Just Starting Now. This Stock Will Soar.
http://www.DailyWealth.com/Oil_Report
Cuba:
Cuba produced 52,600 bbl/d of oil in 2008, roughly the same as 2007. In 2008, the country consumed an estimated 176,000 bbl/d, making the island a net oil importer. Cuba's oil production has increased significantly in the past two decades, with the country only producing 13,000 bbl/d in 1988. Most of Cuba's oil production occurs in the northern Matanzas province, producing a heavy, sour crude that requires specific processing. Much of this production occurs onshore, though there is some offshore production in shallow coastal waters. Cuba’s oil production seems to have largely stabilized in the near term, with any additional increases in production dependent upon the discovery of substantial new reserves (see below). In 2009, state-owned Cupet cancelled its production sharing agreements with Canadian firms Sherrit and Pebercan for the Block 7 area, which represents about two-fifths of the country’s total oil production.

Offshore Exploration
There has been considerable interest in exploration activities in Cuba's offshore basins, especially in the Gulf of Mexico. The U.S. Geological Survey (USGS) mean estimate for undiscovered oil reserves in the North Cuba Basin (the basin north and west of the island in the Gulf of Mexico) is 4.6 billion barrels. Cupet estimates that all of Cuba’s offshore basins could contain in excess of 20 billion barrels of undiscovered oil reserves. However, actual exploratory drilling in the area has been, to date, quite limited. In July 2004, Repsol-YPF announced that its exploratory well in Block N27 in the Gulf of Mexico had discovered high-quality crude oil, but not in commercially-viable quantities.

Oil and Gas Articles

Mineral Rights

Geology News



In 2007, Cupet and Venezuela’s PdVSA concluded an agreement to jointly explore Cuba’s offshore areas. A consortium of Repsol-YPF (40 percent and operator), Norsk Hydro (30 percent) and ONGC-Videsh (30 percent) announced that it would drill an offshore exploratory well in 2010-2011. The consortium has exploratory licenses in seven blocks in the Gulf of Mexico. According to media reports, Cuba also signed offshore exploration agreements with Russia’s Zarubzhnieft in 2009. Petorbras announced in July 2009 that it had completed seismic work at its offshore block (Block 37) in the country. As of late 2009, no Chinese oil companies were drilling in Cuba’s offshore basins, according to media reports.


Barbados:
While Barbados does not have significant crude oil reserves, it does maintain a small amount of domestic production. Oil production in Barbados during 2008 averaged 1,100 bbl/d, while the country consumed an estimated 9,000 bbl/d. As Barbados has no refining capacity, its oil is mostly sent to Trinidad and Tobago for processing, with the refined products returned for domestic consumption.


Oil Refining

According to OGJ, the Caribbean region has a combined 1.8 million bbl/d of nominal nameplate refining capacity. Smaller refineries mostly produce petroleum products for local demand, whereas the larger facilities are geared towards exports to the United States and other markets. The Caribbean is also an important storage location for crude oil brought in from outside the region.

The largest refinery in the Caribbean is the Hovensa facility in the U.S. Virgin Islands, with crude distillation capacity of 495,000 bbl/d. Hovensa, a joint venture of PdVSA and Amerada Hess, sends most of its refined product output to the United States: in 2008, the U.S. Virgin Islands sent 320,000 bbl/d of refined products to the United States (see the EIA Petroleum Navigator for more details). Other large facilities in the region include the 320,000-bbl/d Isla refinery in the Netherlands Antilles, operated by PdVSA; the 230,000-bbl/d San Nicolas in Aruba, operated by Valero (according to company statements in October 2009, this refinery was shut down in the third quarter of 2009 due to falling discounts for heavy sour crude varieties); and the 165,000-bbl/d Pointe-a-Pierre in Trinidad and Tobago, operated by Petrotrin. Both the Hovensa and Isla refineries source the bulk of their crude oil supplies from Venezuela.
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Re: Caribbean geology

Postby chiggerbit » Sun Jan 17, 2010 6:24 pm

If you look closely at the map at this first link, you'll see that it shows the Cocos Plate moving towards the east and appearing to bump against the Caribbean Plate, and it shows the Caribbean Plate moving west. but I wonder if that information is out-of-date, as some information that I've posted above seems to indicate that the Caribbean Plate remains stationary in relation to the middle of the earth.

http://en.wikipedia.org/wiki/File:Plates_tect2_en.svg

Regardless, what I find interesting about the complexity of the Caribbean plate and it's geology is its possible relationship to plate tectonics of the North American plate. I think Jeff had posted something about the Farallon Plate a long time ago.

http://en.wikipedia.org/wiki/File:Plates_tect2_en.svg

Image

The Farallon Plate was an ancient oceanic plate, which began subducting under the west coast of the North American Plate— then located in modern Utah— as Pangaea broke apart during the Jurassic period. It is named for the Farallon Islands which are located just west of San Francisco, California.

Over time the central part of the Farallon Plate was completely subducted under the southwestern part of the North American Plate. The remains of the Farallon Plate are the Juan de Fuca [off the coast of California, Oregon, Washington?], Explorer and Gorda Plates [off the coast of northern California], subducting under the northern part of the North American Plate, the Cocos Plate subducting under Central America and the Nazca Plate subducting under the South American Plate.



It is thought that much of the plate initially went under North America (particularly the western United States and southwest Canada) at a very shallow angle, creating much of the mountainous terrain in the area (particularly the southern Rocky Mountains). A large fragment of the subducted plate is believed to presently be in the mantle under eastern North America. It is also speculated that the associated spreading center was also subducted and may be responsible for the rifting which has created the Basin and Range geologic province.

The Farallon Plate is also responsible for transporting old island arcs and various fragments of continental crustal material rifted off from other distant plates and accreting them to the North American Plate. These fragments from elsewhere are called terranes (sometimes, "exotic" terranes). Much of western North America is composed of these accreted terranes.


So, what I'm wondering is if the Haiti quake could have been triggered by the proximity of the Caribbean Plate to this Farallon Plate, particularly the Cocos Plate.
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