Sri Lanka is an Island State constituting of a total area of 65,610 sq km;
land: 64,740 sq km
water: 870 sq km
The highest point is 2,524 meters at the Pidurutalagala mountain.
The coordinates of Sri Lanka is 7°N 81°E, making it not too far from the equator currently.
There, you will see mountains jetting high,
Plenty of white sand beaches.
And Plains. Most of the island consists of shallow sloped rock formations that range from 30 to 200 meters.
Let us go on the adventure through how and when these landscapes were formed.
 |
| Major Geologic Units of Sri Lanka and Major Cities http://www.geo.shimane-u.ac.jp/spfs/g_students/mext/08sansfica/Sansfica08_2L.jpg |
Rock type: around 85% of Sri Lanka's surface lies on a 2 billion year old Precambrian Strata. This is subdivided into these five main regions.
1. Limestone- Hornblende gneiss. From the tertiary period
 |
| Limestone https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwkX3RCldZIIVNTC8BtGI2m7fCYbIS5XcAffoYXOBnT4qUtngoMatL3h2f-VKVIT8dhMlNRNVSUQKncjVuKbyenRu_CdV0j4-bFxA5SVXNaxOmNO-ecdYu4cYs1b1mqzvHyeiBczrTVejY/s320/Rama's-Bridge-or-Adam's-bri.jpg |
 |
| Standing Buddha in layered garnet-biotite gneiss of Highland Complex, Pollonnaruwa, northern Sri Lanka. http://www.staff.uni-mainz.de/kroener/Sri%20Lanka.htmHighland Complex- |
3. Kadugannawa Complex- Large deposit of mica, hornblende, and amphibiotic minerals (meaning it was living in water during the early stage of its development, and on land the rest).
4. Vijayan Complex- Consisting of migmatities (a mixture of metamorphic and igneous rocks). About 1100 million years old.
5. Wanni Complex- Another large swath of migmatites- a combination of gneisses and granitoids. 1000 to 1100 million years old.
 |
| Highly deformed amphibolite layer (mafic dyke) in granitoid gneiss, Wanni Complex, NW Sri Lanka.http://www.staff.uni-mainz.de/kroener/Sri%20Lanka.htm |
The metamorphic rocks in these complexes have created the jetting mountains and surrounding lowlands. They have mixed together with the previous igneous rocks from Pangaea, have been pressurized over time, and have degraded. The violent interactions between the two rock types has settled over time to create the features of modern Sri Lanka.
Now, I'm going to take you back to when what is now Sri Lanka was nothing more than molten lava in the mantel of the Earth. Immense pressure (and possibly drifting over a vertical plume) caused this liquid rock to rise through the lithosphere, and break through the oceanic and continental crust in a violent upheaval of silica, carbon, and other elements.
Sri Lanka's major complexes were formed long ago, when the supercontinent Pangaea was being ripped apart by the continental plates. forming a new continent by the name of Gondwana!
The image below illustrates the formation of what is now Sri Lanka from what was Gondwana. Sri Lanka use to be nestled with Antarctica and Africa before getting swept North by the Indian Plate for the smooth ride. The rare minerals found in Tanzania and Antartica correlate with ones found in Sri Lanka, which gives evidence of the similar geologic activities.
 |
| http://upload.wikimedia.org/wikipedia/commons/1/10/Snider-Pellegrini_Wegener_fossil_map.svg |
If you full screen the video below and look at the lower left hand corner under what is outlined as India, there is a red circle that symbolizes Sri Lanka. The original landmass came from Gondwana and then experienced new geologic activity during the separation of the continent. It took a very interesting and individualized path.
In GEOLOGIC TIME, Sri Lanka has not been in it's location for long. It now lies smack dab in the middle of the Indian Plate, meaning there are not many instances of the plate interactions causing volcanic activities, earthquakes, or major plate movements. As India is colliding with the Eurasian plate, it is subducting into the mantel under the Eurasian plate. The violent process is piling up geologic material (or converging) that is creating the Himalayas. Sri Lanka is coasting clear from the effects of being eaten up by other continental crusts.
BUT...
Even though Sri Lanka has been in a steady state since Gondwana, Sri Lanka's geology is not sailing through the Bay of Bengal without complete safety from geologic
 |
| Shifting plates cause tsunami's like the event in 2004, which hit Sri Lanka. http://upload.wikimedia.org/wikipedia/commons/4/47/2004_Indonesia_Tsunami_Complete.gif |
This geologic structure has been perceived by humans as being useful industrial and agricultural resources. A boom of gems and precious stones are being mined in Sri Lanka- sapphires, rubies, alexandrite, along with the discovery of Rare Earth Elements which have high medical and technological uses. Silica, quartz, graphite, marble, limestone, clay, phosphates, mica, feldspar, cement, and mineral sands. Sri Lanka exported $42.7 million worth of minerals in 2012 alone.
 |
| Serendibite. $1.8-2 Million/Carat Consists of calcium, magnesium, aluminum, silicon, boron, and oxygen. http://listverse.com/2007/12/02/top-10-rarest-gems/ |
 |
| Photo from a private mining company website in Sri Lanka. http://www.miramaminerals.com |
 |
| http://www.sndgems.com/Sapphire-Ring-Buying-Guide-How-to-Evaluate-Identify-and-Select-Certified-Sapphires-and-Fine-Sapphire-Jewelry-Online.htm |
Sources
http://www.geo.shimane-u.ac.jp/spfs/g_students/mext/08sansfica/sansfica08.htmlhttp://geography.about.com/library/cia/blcsrilanka.htm
http://www.sinhalite.com/images/my-collection/Sri-Lanka-Madagascar-Gondwana.pdf
http://www.pdn.ac.lk/cjsbs/abstract/40.2/9.%2040.2.9%20Burdigalian.pdf
http://www.pdn.ac.lk/cjsbs/abstract/40.2/9.%2040.2.9%20Burdigalian.pdf
http://0-www.sciencedirect.com.skyline.ucdenver.edu/science/article/pii/0301926894900418
https://www.princeton.edu/~achaney/tmve/wiki100k/docs/Geography_of_Sri_Lanka.html
http://thakshana.nsf.ac.lk/pdf/JNSF1-25/JNSF8_1/JNSF8_1_75.pdf
http://minerals.usgs.gov/minerals/pubs/country/2012/myb3-2012-ce.pdf
No comments:
Post a Comment