Hampton Beach - A Story in Pebbles EarthCache

Hampton Beach - A Story in Pebbles

Hampton is a community in the Canadian province of Nova Scotia, located in Annapolis County. It overlooks the Bay of Fundy with a lighthouse that was originally lit by kerosene when it was built in 1911. The light was changed to electric in the 1940's.  In 2001, the lighthouse became the second in the Maritime Provinces to be passed over to a non-profit community group through the federal government's lighthouse transfer initiative.

Hampton has a large beach of smallish to medium size well rounded stones of various sizes and colors. The beach is U-shaped with a fresh water feed from Gaskill brook on the west side and Chute Cove on the east side. Chutes cove is also the location of the Hampton wharf.

Beach stones - How are pebbles formed?

The rock that makes up the land beneath our feet is called bedrock. After many years, bedrock fractures and breaks due to physical and chemical weathering. Resulting fragments are moved by wind, water, and ice (eroded), then transported and eventually deposited in sedimentary environments like rivers, lakes, and beaches. During transportation, fragments collide with one another and become smooth and rounded. This tumbling process creates smooth pebbles or stones.

As with all other rocks, there are three beach stones types according to how they originated: Igneous, Metamorphic and Sedimentary beach rocks. Igneous rock is formed by the cooling of magma (molten rock) inside the Earth or on the surface. Sedimentary rocks are formed from the products of weathering by cementation or precipitation on the Earth's surface. Metamorphic rocks are formed by temperature and pressure changes inside the Earth.

Minerals make up rocks

A mineral is a naturally occurring inorganic element or compound having an orderly internal structure and characteristic chemical composition, crystal form, and physical properties. Common minerals include quartz, feldspar, mica, amphibole, olivine, and calcite.

A rock is an aggregate of one or more minerals, or a body of undifferentiated mineral matter. Common rocks include granite, basalt, limestone, and sandstone.

The Bay of Fundy's seafloor is covered with glacial landforms created by a continental ice sheet that once covered the entire area and retreated about 14,000 years ago. The glaciers created complex and highly variable seafloor geology within the bay.

Lava flows may harden along the coast and form cliff structures before making contact with the sea. Wave action erodes the rock into grains and clasts which eventually get washed up as black sand on beaches. Much of the dark sand found on beaches originates from mafic rocks like basalt and gabbro.

What causes pebble beaches?

Pebble beaches often form where cliffs are being eroded, and where there are higher-energy waves.  A sandy beach typically has a gentle sloping profile, whereas a shingle beach can be much steeper. The size of the material is larger at the top of the beach, due to the high-energy storm waves carrying large sediment.

There are many factors that determine what kind of beach occurs on any part of the coast. The shape of the coastline, the local geology and the prevailing weather conditions are all significant factors. The size of particles that make up a beach are often a reflection of the energy of the waves that hit the shore. In low-energy environments, such as shallow bays or estuaries, we often see very fine particles such as silt or mud deposited. Higher-energy beaches are often characterized by larger particles, such as pebbles or even boulders.

Impact of Shape of Cove and High energy?

Coves usually form through the process of weathering. Weathering is the process of breaking down or dissolving rocks on Earth's surface. Rain, wind, ice, chemicals, and even plants can weather rock. The rocks surrounding a cove are often soft and vulnerable to weathering.

Depending on the location, coastlines can be categorized as high energy or low energy. High energy coasts are usually characterized by:-Strong wave action, typically during the winter months-The rate of erosion usually exceeds the amount of material that is deposited. Main features usually are big cliffs and headlands. Low energy coasts are generally found where:-Wave energy is less powerful-More sediment deposited than lost-Landforms include beaches and spits.

Clasts

Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock. A clast is a fragment of geological detritus, chunks and smaller grains of rock broken off other rocks by physical weathering.

Clastic rocks are formed by erosion, reworking, and transportation of rock components, deposition and sedimentation of the material, and compaction and diagenetic processes. Typical members of this important group of rocks are conglomerate, sandstone, siltstone, shale, and claystone. The classification in the main types (sandstone, siltstone, and claystone) follows the grain size classification for clastic sediments.

Here is an example of the clast found along the coast of the Bay of Fundy. Look at all of the different sizes of clasts in there! The wave energy in this particular area is very high, which you can tell by the lack of small sand grains and the prevalence of much larger clasts (pebbles-boulders).

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Note: Lower tide levels will be needed to view all the differences

Questions:

1. How wide and deep is the beach cove?

2. Which type of stones Igneous, Metamorphic and Sedimentary are on the beach?

3. Which type of stone is the most common?

4. What causes the rocks on this beach to be so smooth and rounded?

5. What makes the stones different colors?

6. How many different coloured stones can you find?

7. Why do these different types of rocks accumulate on this beach?

8. 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.