for National Geographic News
Tom Meierding has always been fascinated by graveyards. Over the last 25
years, he's visited more than 700 cemeteries and measured about 15,000
tombstones to see what kind of environmental secrets they might
reveal.
Meierding is a geomorphologist at the University of
Delaware. He uses the tombstone data to determine past environmental
conditions and compare them with modern pollution
levels—information that's useful to art conservationists, policy
makers, urban planners, and others.
"Cemeteries have been among the most durable of cultural landscapes, preserved even in cities where competition for land is intense," he said. "If you know the scientific basis for environmental degradation, you can fight it more effectively."
His tombstone studies showed, for example, that much of the degradation to stones, monuments, and buildings in the Northeast United States is the result of environmental factors of 70 years ago. The assumption had been that the destruction was caused by the more recent effects of acid rain.
Rocks of Ages
Geomorphologists study the rates at which landforms develop and change, and the human and natural forces that affect that change, such as ice, wind, rain, waves, climate, and gravity.
Two decades ago, Meierding realized that "no one had quantified the weathering rate of rocks in rainy versus dry weather."
Baseline weathering rates enable scientists to determine whether rocks in a given area are weathering as a result of normal processes or at an accelerated rate as a result of environmental or other unusual conditions.
"The problem with studying weathering in nature is that you have no date on the rocks, no way to know if they've been moved, or how long they've been in a place," said Meierding.
Marble tombstones, on the other hand, offer an ideal testing medium because they are usually engraved with dates.
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