On his first voyage to the area in 1770, British navigator James Cook named this area Doubtful Harbour, as he thought it unlikely he could sail safely into the narrow entrance, turn the ship and come out again. It was renamed Doubtful Sound by European whalers in the 1880s.
But did they correctly identify it as a sound? Is Doubtful Sound a sound or a fjord?
Though fjords and sounds are both bodies of water, there are some distinctive differences between the two and these relate to how they are created.
A fjord forms when a glacier retreats and the sea fills the valley that remains. The valley often has steep, near vertical sides that extend deep under water. The sea floor is often flat and deeper at the landward end than the seaward end, due to glacial moraine deposits.
A sound is created by a river carving out a valley that is subsequently filled by sea water. This produces a long inlet where the sloping valley hillsides descend to sea-level and continue beneath the water to form a sloping sea floor.
The Questions
To log this Earthcache you will need to answer the following:
- Do you believe Doubtful Sound is a sound or a fjord?
- On what do you base this assessment?
- Why do you think the namers of the valley got it right or wrong?
Note that your assessment must be based on personal observation of the terrain and shape of the valley, any evidence you see of river or glacial activity and any other geological factors that might lead to your assessment. You do not need to be at the exact coordinates, but you must be far enough into Doubtful Sound to be able to make comprehensive observations. As this location is normally only accessible by boat, consideration of how you got here may also factor into your conclusions. (Feel free to mention your method of access in your log and add a photo.)
If hiking into the area, please ensure you take the necessary precautions to ensure a safe trip. There is a trail, but the area is remote and requires advanced skills.
Please do not put your answers in your logs, but email them to Doctor Owl for approval. Logs that have not been accompanied by the correct answers or which appear to be the result of armchair caching or mere googling will be discretely queried and (if necessary) deleted.