To Log This Cache:
1) Take a look around the tombstones near ground zero. What type of weathering is taking place here? Explain your answer.
2) What affects to you see these tombstones have from the weathering?
3) Take a quick look at the tombstones closest to the water. How has the material for tombstones changed today?
4) Take a selfie with the church in the background of your picture. If you do not want to be in the picture, take an original pic.
Weathering describes the breaking down or dissolving of rocks and minerals on the surface of Earth. Water, ice, acids, salts, plants, animals and changes in temperature are all agents of weathering. Once a rock has been broken down, a process called erosion transports the bits of rock and mineral away. No rock on Earth is hard enough to resist the forces of weathering and erosion.
Weathering and erosion constantly change the rocky landscape of Earth. Weathering wears away exposed surfaces over time. The length of exposure often contributes to how vulnerable a rock is to weathering. Rocks, such as lavas, that are quickly buried beneath other rocks are less vulnerable to weathering and erosion than rocks that are exposed to agents such as wind and water.
As it smooths rough, sharp rock surfaces, weathering is often the first step in the production of soils. Tiny bits of weathered minerals mix with plants, animal remains, fungi, bacteria, and other organisms. A single type of weathered rock often produces infertile soil, while weathered materials from a collection of rocks is richer in mineral diversity and contributes to more fertile soil. Soils types associated with a mixture of weathered rock include glacial till, loess and alluvial sediments.
Physical Weathering:
Freeze-Thaw:
Water seeps into cracks in the stone, freezes, expands, and can crack or break the stone, especially in areas with temperature extremes.
Expansion-Contraction:
The stone expands in heat and contracts in cold, leading to cracking and exfoliation (peeling of outer layers).
Wind Abrasion:
Wind can erode the surface of the stone, especially if the stone is weakened by other weathering processes.
Salt Weathering:
Salt crystals can grow within the stone, exerting pressure that can cause the stone to break down.
Chemical Weathering:
Dissolution:
Acid rain or other acidic substances can dissolve certain minerals in the stone.
Salt Crystallization:
Salts in groundwater can crystallize within the stone, causing expansion and cracking.
Factors Influencing Chemical Weathering:
Climate: Warm, humid climates accelerate chemical weathering.
Rock Type: Certain minerals are more susceptible to chemical weathering than others.
Surface Area: Rocks with a larger surface area weather more quickly.
Biological Weathering:
Lichen and Moss Growth:
Lichens and moss can grow on the stone, producing acids that can damage the surface.
Plant Roots:
Roots of plants can penetrate cracks in the stone and exert pressure, leading to cracking and breakage.
Examples of Biological Weathering:
Tree roots splitting sidewalks or rocks.
Lichen and moss growing on rocks, causing them to crumble.
Burrowing animals creating cracks in rocks.
The weathering of headstones in a cemetery.
The breakdown of carbonate rocks (like limestone and dolomite) by cyanobacteria, lichens, and fungi.
The weathering of rocks by bacteria and algae.