Sand Banks - A Kame Delta-Wash Out EarthCache

Sand Banks - A Kame Delta-Wash Out

North Mountain is a narrow southwest-northeast trending volcanic ridge on the mainland portion of southwestern Nova Scotia, stretching from Brier Island to Cape Split. It forms the northern edge of the Annapolis Valley along the shore of the Bay of Fundy. The ridge traces its history to the Triassic period when this part of Nova Scotia occupied the center of the supercontinent Pangaea. It is a 201 million year old sequence of tholeiitic basalts, which contains columnar jointing. The hard ridge of basalt resisted the grinding of ice sheets that flowed over the region during past ice ages.

Sand Bank road lies west of Margaretsville and east of Port George on the NS route 362. It is a road that weaves its way down the northside of North Mountain. Sand Banks is a cliff of sand at the end of Sand Bank road just west of McNeily’s Brook.

Prior to the advance of the final ice  an ablating mass of ice sent water northward through the wind gaps, forming a delta in the Bay of Fundy . The surface of the delta is now at an elevation of about 110 feet above mean sea level and extends for two miles west of McNeily. Cobbles and pebbles of South Mountain granite in the kame deposits indicate transport took place of sediments of southern source northward across the Annapolis Valley and North Mountain.

A kame delta or ice-contact delta, morainic delta  is a delta formed by a stream flowing between a valley slope and the margin of glacial ice and is also known as delta moraine. Once it reaches the proglacial-lake located at the terminus of the ice, it deposits the sediments, and after the ice has melted an asymmetrical triangular shape glacial landform (Kame delta) appears.

In this instance the kame delta was formed through a valley on the north mountain and deposited the sand upon entering the Bay of Fundy.  The next ice age the ice pushed up the Bay of Fundy pushing the kame delta back up the mouth of the stream bed. At ground zero, you will see a large deposit of sand from the delta. Glacial till is deposited on the lateral sides of the delta, as the glacier melts.

Following the last glacial advance, which left ice-contact stratified drift on the overridden delta, drainage was re-established during dissolution of the ice mass "long enough to clear the channel of glacial debris, but not long enough to destroy the kames superposed on the delta top.

From the bedrock threshold at Spa Springs, 275 feet above sea level, the channel slopes regularly northward for 4.7 miles, following a rather sinuous course, and emerges on the shore 1.8 miles southeast of Peter's Point, Margaretsville. Here wave erosion is rapidly cutting into a large deposit of cross-bedded, well-sorted medium sand with lenses of fine gravel. The wave-cut front stands 110 feet above the sea and extends for almost two miles along the shore. The surface of the deposit is graded to the slope of the bedrock channel, and thus appears to be a delta formed when the channel was active.

To log this Earthcache visit the viewing location. Please answer the following questions and send in a timely manner to my geocaching profile or email. Answers not received will result in deleted logs.

Note: Geocache GCA1CPB is on the way to the Ropes

   You can park just past this cache in a turn-around area.

   The road is passable by a car.

   The Earthcache is on the shore at the end of the trail.

   Some rope climbing is required. Recommend to bring some gloves.

   Not recommended during high tides.

Questions:

1. How wide is the kame deposit?

2. Why does the beach below the kame have less big rock and more sand?

3. What 2 features do you see east of the kame field nearer the basalt formation?

4. What is the elevation at the beach and the top of the ropes?

5. Post a picture in your log with a personal item or hand in picture to prove you were there.

[REQUIRED] In accordance with the updated guidelines from Geocaching Headquarters published in June 2019, photos are now an acceptable logging requirement and WILL BE REQUIRED TO LOG THIS CACHE. Please provide a photo of yourself or a personal item in the picture to prove you visited the site.