Geological Formation of Panama and Revelations From the New Canal

[JudyS]

This very interesting article from Al Jazeera is about fossils being found in the diggings of the new part of the canal.  It makes a statement about the isthmus rising from the sea.  Recent findings say that is not the way Panama was formed.  The link Plates below says, "...instead of being formed by rising and subsiding ocean levels or existing as a string of islands as scientists previously believed, the Isthmus of Panama was first a peninsula of southern Central America before the underlying tectonic plates merged it with South America 4 million years ago."

Those who are interested in paleontology and plate tectonics might find both of these sites an interesting read.  I found the plates article when I was wondering why the area around Panama City is mainly limestone and sedimentary, but Chiriqui and areas east, before PC, tend to be volcanic.  The plate tectonics explains it.

Canal

Plates

Edited May 25, 2016 by Admin_01
expanded the title for a bit more clarity

[Moderator_02]

In the interest of making the above referenced news article that was labelled "Canal" (http://www.aljazeera.com/blogs/americas/2016/05/panama-canal-project-opens-21m-year-history-160517193235985.html) more accessible, here is the first of two:

Quote

Panama Canal project opens up 21m-year-old history

Despite delays and additional expenditure, the discovery of fossils opens up "a time of exploration".

Tell us what you think

4-5 minutes

When I first started researching the Panama Canal expansion, I never thought I would mention the preservation of the surrounding rainforest and discovery of 21-million-year-old fossils in the same sentence.

But I have since learned that they are all connected.

After almost two years of delays and $2bn in additional expenditure, the expanded 102-year-old waterway is scheduled to open on June 26 this year.

It took 30,000 workers seven years to build the expansion. The consortium of companies that built it boasts that it is "one of the most challenging engineering infrastructure projects worldwide".

A new third lane and existing channels that are deeper and wider will give bigger ships a short cut between the Pacific and Atlantic Oceans.

It's expected to have quite an impact on international maritime trade.

"The size of this canal is second to none and it is unique from the size, to the gates and all the controls," CEO of the consortium GUPC Giuseppe Quarta said.

"This is an expansion of a canal that already works very well. It builds up from a history of 100 years of working efficiently."

The expansion will give bigger ships a short cut between the Pacific and Atlantic oceans [Natasha Pizzey/Al Jazeera]

But there has also been a breakdown in the working relationship between the consortium of construction companies and the government.

They are engaged in a costly battle and are now in the midst of an international arbitration process that could take years to resolve.

The consortium says it has spent $2bn in unforeseen expenses and is seeking reimbursement from the government.

The Panama Canal Authority says the additional costs are due to failings of the consortium and taxpayers should not bear the brunt of its missteps.

Positive surprises

The expansion project has come with some positive surprises as well.

The Panama Canal needs high water levels in order to operate. It is surrounded by a gorgeous rainforest. With its abundant rainfall, it will help keep the water levels of the canal high.

That symbiosis has led the government to protect the rainforest in the area.

A community activist told Al Jazeera that if it was not for this lucky reliance on the rainforest, the area would eventually give way to high rises and resorts.

It took 30,000 workers seven years to build the expansion [Natasha Pizzey/Al Jazeera]

Fifty million cubic metres have been excavated during the expansion project.

Paleontologists from the Smithsonian Tropical Research Institute have taken full advantage of this.

They have been allowed to dig at the site and say it is a new frontier of discovery. One of their most celebrated findings is a 21-million-year-old monkey fossil.

That's when the isthmus of Panama rose from the sea.

Way to Central America

The monkey’s closest relative lives in Africa and that left scientists wondering how it managed to make its way to Central America.

"We are really opening a window to a world we didn't know existed," said Carlos Jaramillo from the Smithsonian Tropical Research Institute.

Through their research, the paleontologists say they are creating a geological timeline about the environment and the migratory patterns of animals in the region.

"For decades, scientists assumed that in the tropics you wouldn't find fossils because the rainfall is very high and no fossils could be preserved," Jaramillo said.

"It's a time of exploration, like paleontologists did in North America 120 years ago."

 

[Moderator_02]

And the second news article that was labelled "Plates" (https://www.sciencedaily.com/releases/2008/07/080729234142.htm):

Quote

Isthmus Of Panama Formed As Result Of Plate Tectonics, Study Finds

Date:

July 31, 2008

Source:

University of Florida

Summary:

Contrary to previous evidence, a new University of Florida study shows the Isthmus of Panama was most likely formed by a Central American Peninsula colliding slowly with the South American continent through tectonic plate movement over millions of years.

 

 

Location of the Panama Canal Basin and other depositional basins in southern Central America.

Credit: PLoS ONE

Contrary to previous evidence, a new University of Florida study shows the Isthmus of Panama was most likely formed by a Central American Peninsula colliding slowly with the South American continent through tectonic plate movement over millions of years.

The study, co-authored by Florida Museum of Natural History researchers Michael Kirby, Douglas Jones and Bruce MacFadden, is published in the July 30 issue of PLoS ONE, the online journal of the Public Library of Science. The study uses geologic, chemical and biologic methods to date rocks and fossils found in sides of the Gaillard Cut of the Panama Canal. The results show that instead of being formed by rising and subsiding ocean levels or existing as a string of islands as scientists previously believed, the Isthmus of Panama was first a peninsula of southern Central America before the underlying tectonic plates merged it with South America 4 million years ago.

"Scientists knew Panama was a North American peninsula, possibly as early as 19 million years ago because fossils that are closely related to North American land mammals, such as rhinos, horses, peccaries and dogs have been found in the Panama Canal during ongoing maintenance," said Kirby, lead author of the study. "But we were not certain when this peninsula first formed and how long it may have existed."

The canal's maintenance also exposes sediment layers and marine animal fossils, as well as strata of rocks and clay specific to numerous environments, including lagoon, delta, swamp, woodland and dry tropical forest.

Previous studies placed marine sediment as the youngest layers, suggesting the peninsula was submerged before finally joining with South America. The current study revises the time order of strata, however, and concludes that the Panamanian peninsula joined with South America roughly 4 million years ago.

Deep-sea deposits in one sediment layer suggest a short-lived strait may have existed across the Panama Canal Basin between 21 and 20 million years ago," said Jones, director of the Florida Museum of Natural History. "However, these short-lived straits probably had little impact on the long-term evolution of Central America's flora and fauna."

Kirby explained that because of numerous geologic faults resulting from tectonic plate movement that continues today, there is no area in Panama that allows a full view of the strata making up the land.

"We realized there was a problem with our previous understanding of the stratigraphy, or layering of sediments, in Panama," Kirby said.

The authors used alternative methods such as strontium isotope dating of fossils and re-analysis of vertebrate fossils to better determine the geologic sequence of the Canal.

"There's always missing information, like pages out of a book, when it comes to figuring out which layers came first and which were formed later," Kirby added.

Anthony Coates, a staff scientist emeritus at the Smithsonian Tropical Research Institute in Panama who has extensively studied the geological history of the rise of the Central American isthmus, said the study brings together a diverse array of geologic evidence that convincingly suggests Central America was a peninsula and not a group of islands.

"They have made an important contribution to the land-based geologic evidence of the plate tectonic history of the formation of the Isthmus," said Coates, who did not participate in the study. "Their results have important consequences for the nature of the global change engendered by the rise and closure of the isthmus."

One of the major effects of the formation of the Isthmus of Panama was the intensification of the Gulf Stream in the Atlantic Ocean. While the area that is now Panama was still a peninsula, ocean currents moving north along the north coast of South America spilled over to the Pacific Ocean through the wide Central American Seaway, also called the Atrato Seaway. As tectonic plate movement joined the peninsula with South America to form the present-day Isthmus of Panama, equatorial ocean currents between the Atlantic and Pacific were cut off, forcing water northward into the Gulf Stream current.

"The strengthened Gulf Stream, in turn, delivered enough moisture to allow the formation of glaciers across North America," Kirby said.