What is a bay?
A bay is a recessed, coastal body of water that directly connects to a larger main body of water, such as an ocean, a lake, or another bay. The land surrounding a bay often reduces the strength of winds and blocks waves. Bays may have as wide a variety of shoreline characteristics as other shorelines. In some cases, bays have beaches, which are usually characterized by a steep upper foreshore with a broad, flat fronting terrace.
Formation of Bays and Headlands:
Bays form where less resistant rocks, such as sands and clays, are eroded, leaving bands of stronger, or more resistant rocks, (such as chalk, limestone, and granite), which form a headland or rocky peninsula. Refraction of waves occurs on headlands concentrating wave energy on them, so many other landforms, such as caves, natural arches, and stacks, form on headlands. Wave energy is directed at right angles to the wave crest, and lines drawn at right angles to the wave crest (orthogonal) represent the direction of energy expenditure. Orthogonal converge on headlands and diverge in bays, which concentrates wave energy on the headlands and dissipates wave energy in the bays. In the formation of sea cliffs, wave erosion undercuts the slopes at the shoreline, which retreat landward. This increases the shear stress in the cliff-forming material and accelerates mass movement. The debris from these landslides collects at the base of the cliff and is also removed by the waves, usually during storms, when wave energy is greatest. This debris provides sediment, which is transported through longshore current for the nearby bay. Joints in the headlands are eroded back to form caves, which erode further to form arches. These gaps eventually collapse and leave tall stacks at the ends of the headlands. Eventually, these too are eroded by the waves. Wave refraction disperses wave energy through the bay, and along with the sheltering effect of the headlands, this protects bays from storms. This effect means that the waves reaching the shore in a bay are weaker than the waves reaching the headland, and the bay is thus a safer place for water activities like surfing or swimming. Through the deposition of sediment within the bay and the erosion of the headlands, coastlines eventually straighten out. But then the same process starts all over again.
What is a pocket beach (also known as a quiet beach)?
A Pocket beach is usually a small beach, between two headlands. In an idealized setting, there is very little or no exchange of sediment between the pocket beach and the adjacent shorelines. Pocket beaches are formed by wave refraction. Waves converge on headlands, causing erosion, and diverge in coves, causing deposition of sediment. The shape of pocket beaches is determined by the form of the surrounding bedrock. The forces of waves, currents and tides determine the type and amount of sediment deposited. There are several factors that threaten pocket beaches. The construction of seawalls and other artificial structures reduce the amount of sediment available to replenish pocket beaches. In such a case, all the small sediment will eventually be washed out to sea. The sediment source of a particular pocket beach may not be readily apparent since sediment can be transported along the shoreline for some distance.
What is Honeycomb Weathering?
Honeycomb weathering is a form of cavernous weathering. It consists of regular, tightly adjoining, and commonly patterned cavities that are developed in weathered bedrock; are less than 2 cm (0.79 in) in size. Honeycomb weathering typically develops in siliceous rocks. It can be found in all climate types but is most prolific in salt-rich environments, such as deserts and coastal zones. The common factors in the environments in which it is found are high salt concentrations and frequent or occasional desiccating conditions. Many explanations have been proposed for honeycomb and other cavernous weathering. These explanations include marine abrasion; wind corrosion; mechanical weathering resulting from short-term temperature variations; chemical weathering of the interior of the rock (core-softening) under a protective crust (case-hardening) followed by the mechanical removal of the softened material; biogeochemical weathering by lichens; temperature variations acting on salt efflorescence in coastal regions; and salt weathering. Most commonly, researchers have advocated salt weathering as the primary explanation for the formation of honeycomb weathering. Currently, it is considered to be polygenetic in origin; being the result of the complex interaction of physical and chemical weathering processes, which include salt weathering.
Logging Requirements:
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Using the information that you’ve learned in the description and the observations that you saw at the GZ, is this area considered to be a bay? If so, what are some characteristics of bays that you see at Clarence Cove?
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How were the waves at the GZ? Were they rough or calm? Do they seem to be eroding the pocket beach?
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Travel to the waypoint near the GZ. You will notice a large limestone rock formation near the ocean. Is this rock formation affected by honeycomb weathering? If so, how large are the holes in the rock?
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Sources:
https://geographyas.info/coasts/features-of-erosion/
https://en.wikipedia.org/wiki/Headlands_and_bays
https://en.wikipedia.org/wiki/Pocket_beach
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