Logging Requirements: (You must visit this cache location, answer the questions below. Please use the Message Centre link above on this cache page to send the answers to to the cache owner.
- Using your GPSr measure and report the closest distance and the bearing from the beach at the edge of Lake Ontario to the Lighthouse.
- Based upon the cache description and your observations on the beach, which of the two types of water movement was predominant in creating the Toronto Islands?
- Based on the information in the cache description and your observations on the beach can you explain, in geological terms, why the lighthouse is found at it’s present proximity to the lake rather than it's original proximity?
- From your position on the beach are you be able to take a picture that captures both the beach and the lighthouse in the same frame?
- While standing on the beach and looking between 75 deg and 90 deg magnetic, report anything that is man-made and would now interfere with the geological process that created and maintained the Toronto Island sand-spit.
Optional
- A photograph of the lighthouse from as far away as possible, towards the beach.
- To illustrate the curvature of the earth, the true visible horizon can be calculated. Using the formula
d ~= 3.57*sqr(h), (where d is the approximate, theoretical distance to the horizon in kilometers and h is the approximate height of the lighthouse in meters.) Report, theoretically, disregarding refraction, how far someone at the top of the lighthouse could see to the true southern horizon.
The Toronto Islands is a rare urban example of sand-spit formation in the Great Lakes region. There are many sand-spits with which you may already be familiar. Locally, in Canada, Long Point, ON and in Europe, the Curonian Spit in Lithuania and Kaliningrad (Russia) are both EarthCaches on UNESCO World Heritage Sites.
A spit is a type of bar or beach that develops re-entrant (an angle pointing inwards). This spit once connected to a headland near the Don River in Toronto. In 1852, a storm flooded sand pits on the peninsula, creating a channel east of Ward's Island. The channel was widened and made permanent by a violent storm in 1858. The channel became known as the Eastern Gap. The process of longshore drift formed the Toronto Islands.
Longshore drift most often occurs where waves (caused by winds in the Great Lakes) meet the beach at an oblique angle, and backwashing perpendicular to the shore ensues, moving sediment down the beach in a zigzag pattern. In the Toronto part of Lake Ontario the prevailing wind is southwesterly. Longshore drifting can also occur from longshore currents, which transport sediment through the water alongside the beach.
The flow from the Niagara River to the south across Lake Ontario causes a counter-clockwise east-to-west current, which has, over time since the end of the last ice age, about 10,000 years ago, deposited alluvial deposits from the erosion of the Scarborough Bluffs at the south end of the harbour. The islands were originally a 9 km peninsula or sand spit extending from the mainland.
To the east of the Toronto Islands is the man-made Leslie Street Spit. It was started in the late 1950's and it continues to be the site for the disposal of dredged material from the Outer Harbour and surplus fill from development sites within Toronto. There are also a number of features along the south shore of the islands, such as break waters and groynes, that help prevent shoreline erosion.
The cache coordinates will take you near to the Gibraltar Point Lighthouse, which is located on the Toronto Islands. Construction of the lighthouse started on the shoreline in 1803 and was completed in 1808. It is the oldest existing lighthouse on the Great Lakes. It was extended to it’s present height of about 25 meters in 1832. Please use this location (and the cache page) as the starting place to gather information to answer the questions required to log this cache.
To reach the Toronto Islands you will need a boat or you can see the ferry schedule here. It is about 3.5 km from the Ward's Ferry, or about 2.0 km from the Hanlan's Ferry to the Lighthouse.
Armchair logging will not be permitted and any logs so determined will be deleted.
This cache page was inspired by information derived from Wikipedia