The GraveNet Project

Physical and Chemical Weathering
Grave sites, like all natural and man-made objects, are subject to physical weathering forces. Among these forces are wind, water, ice, movement of the earth's crust and plant growth. At this grave site found in Evergreen Cemetery, Leominster, Massachusetts we see a maple tree (approximately 100 years old) that has created considerable damage to the granite post and iron fencing that originally surrounded this resting place. If you click on the photograph you will see that the corner post and lower iron rail have virtually become part of this tree's trunk. The top rail is now missing from two sides. The tremendous pressure placed on the granite by the slow growth of this tree has been great enough to split the post in half!
When you look at this site today you can imagine that family members planted the tree to provide shade for their visits to the grave. Little did they know that over time this tree would play a major role in destroying the monument they erected.
Chemical weathering can also play a major role in destroying gravestones over a long period of time. Among the major foces of chemical weathering we find extreme temperature changes and acid precipitation. At this grave site, again in Evergreen Cemetery, we see a limestone monument that has been seriously erroded by these forces over the past hundred or so years. If you click on the photograph you will have a closer view of the damage to this gravestone. Can you identify the animal that rests atop this marker? Why do you think limestone markers are affected more by acid rain than those of granite or slate?

Weathering of Grave Site In this marker we see another example of physical weathering ... or do we? Unfortunately on a rare occasion you will encounter acts of vandalism in cemeteries. At this grave site we can see a slate gravestone that has broken at the base and fallen to the ground. It's interesting that this marker is still serving its purpose. It actually resembles modern-day "flat" markers that are quite common.
Plan a trip to a cemetery in your town to look for evidence of physical and chemical weathering. Record your findings with writings and photography and submit them to CommunityNet Student Publishing.