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Open Access e-Journal
Earth Science India- www.earthscienceindia.info
Popular Issue, VI (IV), October, 2013, p. 1-13
Geology of the Isthmus of Panama, history of the
Panama Canal and a visit to the Barro Colorado Island
Arun Kumar
Around twenty million years ago the Central
American Seaway once separated the continents of
North and South America that allowed the waters
of the Pacific and Atlantic Oceans to mix easily.
Since then the two plates, the Cocos and the
Caribbean, of the Earth’s crust began to collide
into one another, forcing the Cocos Plate to slide
under the Caribbean Plate thereby creating
underwater volcanoes.
The
Fortieth Annual Meeting of the American Association of Stratigraphic
Palynologists (AASP) was held in Panama City, Panama, between September 8 and 12, 2007. I
attended this conference, which was quite memorable for me because this event gave me an
opportunity to travel to Central America and see the exotic Neotropical plants and meet the
people from this part of the world. I saw the functioning of the world famous Panama Canal and
also visited the tropical Barro Colorado Island (BCI) famous for its very high biodiversity and its
unique native flora and fauna.The Smithsonian Tropical Research Institute (STRI) based in
Panama City has a research center on this island that carries out research on diverse aspects of
biology, the environment and paleontology. The center is visited by interested researchers and
students from all over the world. In this article, I present a short account of the geology of this
region and briefly describethe geological evolution of the Isthmus of Panama. An interesting
account of the history of the Panama Canal and a discussion about the biodiversity, flora and
fauna of the BCI is also presented. I was able to meet my Panamanian economist friend, Dr.
Hernan Arboleda, from my student days at Michigan State University, USA, who treated me to a
dinner at an exclusive Argentine Steak House and drove me all around Panama City till very late
in the night. I had met Hernan after 32 years without any contact in between. He got the surprise
of his life when I called him from my hotel room and I was able to find his phone number from
the local telephone directory. View this very interesting video of Panama Canal Timelapse
(Website 14).
Panama is a small country in Central America bordered by Costa Rica in the north and
Colombia in the south (Figure 1). Panama City, a large, modern metropolis is the capital city
located on the Pacific coast of the country (Figures 2 and 3).This country has around 15,000
people of Indian origin who are mainly employed in the shipping industry and in the wholesale
and retail trades. Most of them are Hindus while Muslims and Sikhs are the minorities. People of
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Open Access e-Journal
Earth Science India- www.earthscienceindia.info
Popular Issue, VI (IV), October, 2013, p. 1-13
Indian origin first came to Panama in the middle of the nineteenth century to work on the
Panama Railways and later in the early 20th century during the US phase of the building of the
Panama Canal. These people were primarily from the various Caribbean Islands and Guyana
where a large number of people from India lived. Since then the Indian community has grown
and new immigrants have come from Gujarat and Sindh (Websites 2 and 3). Panama has a few
Hindu Temples; the one on top of a hill in Tumba Muerto is the biggest and most famous (Figure
4) (Website 3).
Geology of the Isthmus of Panama
The geological evolution of the Isthmus of Panama has been studied by several geologists
and geophysicists and a fair amount of literature is available on this subject. Coates (1997)
provided an extensive description on the formation of the Isthmus of Panama using the Plate
Tectonic Model and explained how the formation of this isthmus led to the Ice Age. Montes et
al. (2012) and Bacon et al. (2013) are among the more recent papers on this subject. The website
of the STRI in Panama has listed a large number of research papers on the various aspects of the
geology of Panama. The following account is rather generalized and simple for a popular
geology article.
Figure 1: Map of Central America showing the location of Panama. (Website 1)
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Open Access e-Journal
Earth Science India- www.earthscienceindia.info
Popular Issue, VI (IV), October, 2013, p. 1-13
Figure 2: Map of Panama showing the location of Panama Canal. (Website 2)
Around twenty million years ago the Central American Seaway once separated the
continents of North and South America that allowed the waters of the Pacific and Atlantic
Oceans to mix easily. Since then the two plates, the Cocos and the Caribbean, of the Earth’s crust
began to collide into one another, forcing the Cocos Plate to slide under the Caribbean Plate
thereby creating underwater volcanoes. Some of these volcanoes formed islands as early as
fifteen million years ago. More volcanic islands filled in the area over the next several million
years. Movement of these two tectonic plates was also pushing the sea floor above the sea level.
Constant erosion of the North and South American landmasses through time resulted in massive
amounts of sediment being deposited in the gaps between the newly formed volcanic islands.
This process continued until the gaps were completely filled. By about 3 million years ago, an
isthmus had formed between North and South America (Coates, 1997; Websites 2 and 5).
The false-colour image of Panama using data obtained in February 2000 by the Shuttle
Radar Topography Mission (SRTM) shows the colours’ relationship to height. Green shows the
lowest elevations just above sea level. Yellows and then tans show progressively higher
elevations with white being the highest (Figure 5). The ability of the SRTM to penetrate clouds
and make three-dimensional measurements has allowed the first complete high-resolution
topographic map of all of Central America (Website 5).
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Open Access e-Journal
Earth Science India- www.earthscienceindia.info
Popular Issue, VI (IV), October, 2013, p. 1-13
Impact of the Isthmus of Panama on the earth's climate,
environment and biodiversity
Earth scientists believe the formation of the Isthmus of Panama is one of the most
important geologic events in the last 60 million years because it had an enormous impact on the
evolution of planet Earth's climate and environment. By shutting down the flow of water
between the two oceans, the land bridge rerouted the ocean currents in both the Atlantic and
Pacific Oceans. The Atlantic currents were forced northward and eventually established into a
new current pattern that we now call the Gulf Stream. With warm Caribbean waters flowing
toward the northeast Atlantic, the climate of northwestern Europe and eastern North America
grew warmer. It also influenced ocean and atmospheric circulation patterns, which regulated
patterns of rainfall, which in turn sculpted landscapes (Website 2).
Evidence also suggests that the creation of this land mass and the subsequent warm, wet
weather over northern Europe resulted in the formation of a large Arctic ice cap and contributed
to the last ice age (Haug & Keigwin, 2004). Those warm currents and associated heated air
flowing over the warm Gulf Stream hold more moisture resulting in increased precipitation that
contributed to the snow pack (Website 2).
Figure 3: An aerial view of Panama City, Panama. (Website 4)
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Open Access e-Journal
Earth Science India- www.earthscienceindia.info
Popular Issue, VI (IV), October, 2013, p. 1-13
Figure 4: The Hindu Temple on the top of Tumba Muerto hill in Panama. (Website 3)
The formation of the Isthmus of Panama also played a major role in the development of
biodiversity on the North and South American Continents. This isthmus made it easier for
animals and plants to migrate between the two continents. This event is known in paleontology
as the Great American Interchange. For instance, in North America today, the opossum,
armadillo and porcupine trace back their ancestors from South America. Likewise, ancestors of
bears, cats, dogs, horses, llamas and raccoons all made the trek from north to south across the
isthmus (Website 2).
Brief history of the Panama Canal
The 77 km long Panama Canal that allows ships to freely travel between the Atlantic
Ocean and Pacific Ocean saves about a 12,875 km long journey around Cape Horn located at the
southern tip of South America (Website 6). Historically Panama was part of Colombia but when
Colombia rejected American plans to build a canal across the Isthmus of Panama, the USA
supported a revolution that led to the independence of Panama in 1903. The Hay-Bunau-Varilla
Treaty allowed the USA to build the Panama Canal and provided for the control of a zone eight
km wide on either side of the canal. The French had earlier attempted construction of a canal in
the 1880s but had failed.
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Earth Science India- www.earthscienceindia.info
Popular Issue, VI (IV), October, 2013, p. 1-13
Figure 5: Topographic map of Panama showing lake in the center, the Panama Canal connects
this lake to the Pacific Ocean. (Websites 3 and 5)
Figure 6: Newly exposed outcrops of the expansion project of the Panama Canal where
geologists and paleontologists study and collect fossils (Website 9).
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Open Access e-Journal
Earth Science India- www.earthscienceindia.info
Popular Issue, VI (IV), October, 2013, p. 1-13
The Panama Canal was successfully built by the Americans between 1904 and 1914.
Thus, Panama got divided into two parts by the U.S. controlled Canal Zone which caused
political tension throughout the twentieth century. The canal contributed almost nothing to the
Panamanian economy. In 1977, U.S. President Jimmy Carter, signed a treaty to return 60% of the
Canal Zone to Panama in 1979. The canal and remaining territory was returned to Panama on
December 31, 1999.After the 1999 hand-over, the U.S. and Panama jointly shared duties in
defending the canal. It takes approximately fifteen hours to traverse the canal through its three
sets of locks and about half the time is spent waiting due to traffic (Website 6).
In September, 2007, work began on a $5.2 billion project to expand the Panama Canal.
This will allow ships double the size of the current Panamax to pass through the canal,
significantly increasing the amount of goods that can pass through the canal. It is expected to be
completed by 2014(Website 6).
Panama Canal Expansion Project and the ‘gold mine’ of fossils
A lot of new geological information and a variety of large numbers of plant and animal
fossils, both large and microscopic, have been unearthed by the massive Panama Canal
Expansion project. Geologists and palaeontologists are getting access to fresh outcrops that are
usually not available in the thickly forested and deeply weathered tropical regions with thick
soils. By analyzing more than 2,000 fossils and the stratigraphic records revealed by each new
rock cut, paleomagnetic data, isotope ratios, carbon signatures, etc., geoscientists are getting a
better understanding of the ancient tropical rain forest of Central America (Website 7).
Figure 7: An aerial view of the Barro Colorado Island. (Website 15)
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Open Access e-Journal
Earth Science India- www.earthscienceindia.info
Popular Issue, VI (IV), October, 2013, p. 1-13
Figure 8: An aerial view of the Barro Colorado Island and STRI facilities. (Website 16)
During the construction of the Panama Canal numerous fossils were collected which
provided evidence for the geological history of Panama when the North and South American
continents were separated by about 150 miles of sea about 20 million years ago. At that time
Panama was the southernmost extent of North America. Fossil finds here have helped us learn
about the animals that inhabited this region and in other regions of North America before the
land bridge between the continents was formed; they include miniature horses and tiny camels
that were just a couple of feet tall. There was also a fearsome predator the size of a black bear,
called a bear dog. Paleontologists are researching the animals and plants that were here at the
time when North and South America finally made contact (Website 8).
Once again miniature camels and horses, a rhinoceros and a giant bear-dog, are among
the fossils unearthed in the recent excavations of the Panama Canal expansion project. These
new findings add significantly to our knowledge of events several millions of years ago that
altered the Earth’s climate and dramatically changed the geographic distribution of plants and
animals (Website 9).
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Open Access e-Journal
Earth Science India- www.earthscienceindia.info
Popular Issue, VI (IV), October, 2013, p. 1-13
The Barro Colorado Island and its biodiversity
The BCI along with its extended five peninsulas is located in the Gatun Lake in the
middle of the Panama Canal (Figure 7). This island was formed when the Chagres River was
dammed, resulting in the rise of the water level that covered lower altitudes of the existing
rainforest leaving only the hilltops as islands in the middle of the lake. The US government set
aside this island as a nature reserve on April 17, 1923. Since 1946 this island has been
administered by the Smithsonian Institution as the Barro Colorado Nature Monument (BCNM).
The BCNM covers an area of 54 km2. The larger fauna of this island disappeared after the lake
was flooded in 1914. The National Geographic Society produced a documentary on the island
titled "World's Last Great Places: Rain Forests" which was released in 2007 (Website 10).
Figure 9: The docking facility of the Barro Colorado Island. Small and large boats sail from here
to other places along the Panama Canal. (Photo: The author)
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Open Access e-Journal
Earth Science India- www.earthscienceindia.info
Popular Issue, VI (IV), October, 2013, p. 1-13
Figure 10: A group of palynologists at the wharf of the Barro Colorado Island (the author is
standing second from right). (Photo: An unknown member of our group)
BCI is home to thousands of species of animals and plants. This island is a very special
place to study tropical biology and is one of the most extensively studied places on Earth and is a
prototype for measuring diversity of plant and animal life around the world. The STRI had
established a research station here in 1928 where scientists from all over the world come to work
(Figures 8, 9 and 10). The island and its flora and fauna are well protected. The BCNM at the
core of the island is the oldest protected area in Latin America. Results of long term global
changes to the forest are unknown, but the climate data from here for the past one hundred years
suggests that the dry seasons might be getting longer and more severe; consequently trees are
more successful in the forest (Website 11).View this interesting BCI Video (Website 12).
Sudden Death of BCI’s Iconic Tree
While reading about the BCI in the STRI’s newsletter (Website 13) I saw a news item
titled “FAREWELL, BCI’S BIG TREE” that described the tree and its aftermath. I was surprised
and wanted to know how this giant tree suddenly died. I contacted Dr. Carlos Jaramillo, of the
STRI, Panama City, who informed me that the tree had just died. Its crown collapsed following a
heavy rain. I feel sad because I had seen this icon of the BCI in September 2007 (Figures 11 and
12).The following description is from the STRI’s newsletter.
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Open Access e-Journal
Earth Science India- www.earthscienceindia.info
Popular Issue, VI (IV), October, 2013, p. 1-13
Figure 11: The trunk of the big tree Ceibapentandra of the Barro Colorado Island in September,
2007. (the author is at right end) (Photo: An unknown member of our group)
Figure 12: The trunk of the big tree Ceibapentandra of the Barro Colorado Island in June, 2013.
Its crown fell due heavy rain and the tree died. (Website 13)
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Open Access e-Journal
Earth Science India- www.earthscienceindia.info
Popular Issue, VI (IV), October, 2013, p. 1-13
On June 1, Karla Aparicio guided a group toward the BCI’s Big Tree; she noticed that the
BCI’s tree was no longer standing. "The whole crown of the tree was on the ground and there
were tons of bees and ants milling around looking lost!" The Big Tree, a kapok
(Ceibapentandra), belonged to the family Malvaceae and was an island icon; tourists and
scientists used it as a backdrop for photos. The tree was host to a large number of plants and
animals like epiphytic orchids, cacti, bromeliads, Spanish moss, sloths, monkeys, bats and birds.
The big tree held the world record for the largest crown and its superlative description is as
follows:
"The very large base was 13m in one direction, tapering to a 2m cylindrical trunk above the
buttressing; ending in a wide crown whose highest leaf reached 47m. What was most remarkable
about the BCI tree was the crown spread, which based on 8 crown radii, averaged 60m in
diameter. This was by far the largest crown known on the planet for a tree with a single stem.
There are several banyans in India and elsewhere larger than this, but none with a single stem.
For a self-supporting crown with no cables or other human impacts, I have only ever measured
two species to exceed 50m in diameter - Ceiba and Albitziasaman." (Website 13).
Acknowledgements: I thank my son Anshuman Kumar for linguistic improvements to this
article.
Suggested Readings:
Bacon, C., Mora, A., Wagner, W.L., and Jaramillo, C. 2013.Testing a new geological model of
evolution of the
Isthmus of Panama in a phylogenetic framework using palms (Arecaceae). Botanical Journal of the Linnean
Society 171: 287-300.
Coates, A. G. 1997. Chapter 1: The Forging of Central America. In. Central America; A Natural and
Cultural
History (Ed. A. G. Coates). Yale University Press, New Haven. 277 p.
Haug, G. H. and Keigwin, 2004. How the Isthmus of Panama Put Ice in the Arctic: Drifting
continents open
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and close gateways between oceans and shift Earth's climate. Oceanus. 42:
http://www.whoi.edu/oceanus/feature/how-the-isthmus-of-panama-put-ice-in-thearctic
Montes, C., Cardona, A., MacFadden, R., Moron, S.E., Silva, C.A., Restrepo-Moreno, S.,
Ramirez, D.A.,
Wilson, J., Farris, D., Bayona, G.A., Jaramillo, C., Valencia, V., and Flores, J.A. 2012. Evidence for middle
Eocene and younger emergence in Central Panama: implications for Isthmus closure. Geological Society of
America Bulletin, DOI: 10.1130/B30528.1.
Web references
Website 1: http://www.worldatlas.com/webimage/countrys/camerica.htm
Website 2: http://en.wikipedia.org/wiki/Indians_in_Panama
Website 3: http://answers.yahoo.com/question/index?qid=20111020141544AAQIJl6
Website 4: http://www.tourist-destinations.net/2013/07/panama-travel-guide.html
Website 5: http://earthobservatory.nasa.gov/IOTD/view.php?id=4073
Website 6: http://geography.about.com/od/specificplacesofinterest/a/panamacanal.htm
Panama Canal
Website 7: http://suvratk.blogspot.ca/2009/07/panama-canal-expansion-boon-to.html
Website 8: http://www.theworld.org/2013/02/panama-canal-fossil/
Website 9: http://smithsonianscience.org/2013/04/first-five-years-of-panama-canal-excavations-reveal-fossil-finds/
Website 10: http://en.wikipedia.org/wiki/Barro_Colorado_Island
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Open Access e-Journal
Earth Science India- www.earthscienceindia.info
Popular Issue, VI (IV), October, 2013, p. 1-13
Website 11:http://newswatch.nationalgeographic.com/2013/08/13/barro-colorado-island-of-magic-diversity-in-themiddle-of-panama-canal/
Website 12: http://www.youtube.com/watch?v=tRGG-XmNMhk
Website 13: http://www.stri.si.edu/english/about_stri/headline_news/news/article.php?id=1681
Website14:
http://www.youtube.com/watch?annotation_id=annotation_655031&feature=iv&src_vid=vi19z4LEi0&v=fA-pnN54uPw
Website15:
http://www.tripadvisor.ca/Travelg294479c3241/Panama:Barro.Colorado.Island.Via.The.Smithonian.html
Website 16: http://www.people.fas.harvard.edu/~crofoot/images/BCI_Stationsmall.jpg
About the author
Dr. Arun Kumar is an Adjunct Professor, Department of Earth Science, Carleton University
1125 Colonel By drive, Ottawa, ON K1S 5B6, Canada.
Email: [email protected]
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