Elephant Island History
Elephant Island is located about 250 kilometers (150 miles) northeast of the tip of the Antarctic Peninsula. Some say Elephant Island got its name from the sighting of elephant seals along its shores; others suggest it comes from its appearance as an elephant head.
Historically, Elephant Island is known as the refuge for explorer Ernest Shackleton and the crew of Endurance when they lost their ship to crushing pack ice in the Weddell Sea in 1915. Shackleton realized their chances of getting rescued from Elephant Island by passing ships were low, so he and five crewmates took a lifeboat to look for help. The remaining crew built makeshift huts by resting their two remaining lifeboats upside down on rocks. To combat the perpetual darkness, they made lamps out of sardine tins, used surgical bandages for wicks, and burned seal blubber oil. Four and a half months later, Shackleton and crew returned with a ship and rescued all 22 men.
Tectonic Plates Overview
The Earth's crust is constantly in motion. Sections of the crust, called plates, push against each other due to forces from the molten interior of the Earth. The areas where these plates collide often have increased volcanic and earthquake activity. The image below shows the locations of the plates and their boundaries in the Earth's crust.
- Convergent boundaries are areas where two plates are pushing against each other and one plate may be subducting under another. The oceanic material of one tectonic plate dives below the material (oceanic or continental) of another tectonic plate into the mantle. The force of one plate going under the other produces a seismic zone, while the other plate's ascent gives rise to mountainous reliefs.
- Divergent boundaries have two plates pulling away from each other and indicate regions where new land could be created such as rifts and valleys.
- Transform boundaries are places where two plates are sliding against each other in opposite directions. The San Andreas fault In California is an example of a transform boundary.
Elephant Island and the Scotia Plate
Geologically, Elephant Island is part of the Scotia Plate. This relatively small plate was formed from oceanic crust and continental fragments that once formed a land bridge between South America and Antarctica. The Scotia plate was formed during the Eocene as the Drake passage opened up. This was part of the process of the breakup of the supercontinent, Gondwana.
The Scotia Plate is a relatively minor tectonic plate situated beneath the Scotia Sea positioned at the southern edge of the South Atlantic Ocean and the northern boundary of the Southern Ocean. Stretching approximately 800 km in width and 3,000 km in length, the plate is in constant motion, drifting WSW at a rate of about 2.2 centimeters (.86 inches) per year. The Scotia Plate links the southernmost Andes to the Antarctic Peninsula.
The Scotia Plate shares its borders with significant neighboring plates: the South American Plate to the north and the Antarctic Plate to the south and west. To the east it borders a much smaller plate, the South Sandwich Microplate which separated from the Scotia Plate about 15 million years ago.
Elephant Island lies in the vicinity of the active boundary of the Scotia and Antarctic Plates. Based on the ages of its rocks, it is thought that Elephant Island was uplifted during the opening of the Drake Passage, about 30 million years ago.
Logging Requirements
Please send a message with answers to the following questions:
- Which type of plate boundary activity most likely created Elephant Island over 30 million years ago?
- What most likely controls how much the Scotia Plate moves in any direction?
- From GZ you will see a smaller island at the tip of the main island. Which of the following two-dimensional shapes best represents the smaller island's shape when looking at it from GZ? (A.) Circle (B.) Rectangle (C.) Triangle
- On which tectonic plate do you reside?
- Post a photo of your gps, caching name, or yourself with Elephant Island in the background.
You may go ahead and log your find, but answers must be received within 10-14 days or your log will be deleted.
Sources
NASA
Latin American and Caribbean Geographic
Science Direct
World Atlas
Wikipedia