GRAVESTONES BITE THE DUST By Johnna Rizzo and Matthew Twombly [A wagon train moves across the plains.] in the 1800s, Texas saw... Mormon pioneers settling the West [Chinese workers lay down rails.] Chinese immigrants building the railroad [One gunfighter shoots another on a 19th century town street.] and notorious outlaws like John Wesley Hardin. [A dusty, rocky cemetery with different grave marker shapes and sizes with mountains in the background.] These figures rest in Concordia cemetery in El Paso, Texas. Their history remains written on well-preserved headstones in this dry, dusty place. [A well-landscaped grassy cemetery with lush green trees in the background. The grave markers are of different shapes and sizes.] Meanwhile... in other parts of the southwest, landscaping intended to make cemeteries look attractive may actually be destroying gravestones. [Silhouetted grave marker bakes in the heat.] Monday, 1 P.M. 110°F [Silhouetted water sprinkler sprays water.] Sprinklers often use well water to keep grass green and lush. Water underground sits around 60°F. [Silhouetted grave marker bakes in the heat with water spraying on it.] Tuesday, 1 P.M. 112°F [Silhouetted grave marker bakes in the heat with water spraying on it.] Wednesday, 1 P.M. 108°F [Silhouetted grave marker bakes in the heat with water spraying on it.] Thursday, 1 P.M. 106°F [Silhouetted grave marker bakes in the heat with water spraying on it.] Friday, 1 P.M. 110°F [Silhouetted grave marker bakes in the heat with water spraying on it.] Saturday, 1 P.M. 112°F [Silhouetted grave marker bakes in the heat with water spraying on it.] Sunday, 1 P.M. 115°F [Granite grave marker shatters.] Over time, the repeated thermal shock can have Ruinous effects.

[A square of granite stone with orange arrows pointing outward at each side and corner.] Stone, like most material, expands as it gets hot. [A smaller square of granite stone with purple arrows pointing inward at each side and corner.] And contracts as it gets cold. [A broken square of granite stone split in half with debris. The left side is larger with orange arrows pointing outward. The right side is smaller with purple arrows pointing inward. with purple arrows pointing inward at each side and corner.] As hot stone is shocked with cold water, exposed areas contract quickly, resulting in cracks. [A granite grave marker that has shattered in several places with debris on the ground. A sprinkler is watering the marker and the grass. Other grave markers in the background are also being watered by a sprinkler.] Granite, a common material for gravestones, is especially good at holding heat. These stones can reach temperatures more than 40 degrees higher than the surrounding air on a sunny day. And the darker the stone, the hotter it gets. Grounds are watered once a day, generally in the midafternoon, when the sun and temperatures are at their peak. [A grave marker with arcs of sprinkler water across it on lush green grass with other markers in the background.] Temperature is not the only problem. The water’s chemical composition plays a role. [Droplets of water, one with five lines drawn to periodic symbols of Iron (Fe, 26), Calcicum (Ca, 20), Silicon (Si, 14), Sulfur (16, S), and Magnesium (Mg, 12).] Southwestern groundwater is high in dissolved Minerals, such as iron, which can stain, and calcium, which can leave deposits. As the water evaporates, these minerals are left behind on the gravestone’s surface, over time forming a skin. Avoiding this buildup requires regular, careful cleanings, But there aren’t enough volunteers to clean every headstone. [Mourners (a young man, woman, and and older woman) stroll through the historic rocky cemetery depicted in the third panel. Some markers display American flags.] Watering in the early morning while graves are still cool can minimize mineral deposition and prevent thermal shock. Even better, keeping to native landscaping is a sure way to preserve the pieces of America's history among the headstones for generations to come. Source: National Center for Preservation Technology and Training, National Park Service

Transcript of “Gravestones Bite the Dust”
by Johnna Rizzo and Matthew Twombly

-IN THE 1800S, TEXAS SAW… MORMON PIONEERS SETTLING THE WEST
-CHINESE IMMGRANTS BUILDING THE RAILROAD
-AND NOTORIOUS OUTLAWS LIKE JOHN WESLEY HARDIN.
-THESE FIGURES REST IN CONCORDIA CEMETERY IN EL PASO, TEXAS. THEIR HISTORY REMAINS WRITTEN ON WELL-PRESERVED HEADSTONES IN THIS DRY, DUSTY PLACE.
-MEANWHILE… IN OTHER PARTS OF THE SOUTHWEST, LANDSCAPING INTENDED TO MAKE CEMETERIES LOOK ATTRACTIVE MAY ACTUALLY BE DESTROYING GRAVESTONES.
-MONDAY, 1 P.M. 110 DEGREES FAHRENHEIT.

SPRINKLERS OFTEN USE WELL WATER TO KEEP GRASS GREEN AND LUSH.
WATER UNDERGRAOUND SITS AROUND 60 DEGREES FAHRENHEIT.

-TUESDAY, 1 P.M. 112 DEGREES FAHRENHEIT.
-WEDNESDAY, 1 P.M. 108 DEGREES FAHRENHEIT.
-THURSDAY, 1 P.M. 106 DEGREES FAHRENHEIT.
-FRIDAY, 1 P.M. 110 DEGREES FAHRENHEIT.
-SATURDAY, 1 P.M. 112 DEGREES FAHRENHEIT.
-SUNDAY, 1 P.M. 115 DEGREES FAHRENHEIT.
-OVER TIME, THE REPEATED THERMAL SHOCK CAN HAVE RUINOUS EFFECTS.

STONE, LIKE MOST MATERIAL, EXPANDS AS IT GETS HOT. AND CONTRACTS AS IT GETS COLD. AS HOT STONE IS SHOCKED WITH COLD WATER, EXPOSED AREAS CONTRACT QUICKLY, RESULTING IN CRACKS.

-GRANITE, A COMMON MATERIAL FOR GRAVESTONES, IS ESPECIALLY GOOD AT HOLDING HEAT.
-THESE STONES CAN REACH TEMPERATURES MORE THAN 40 DEGREES HIGHER THAN SURRROUNDING AIR ON A SUNNY DAY. AND THE DARKER THE STONE, THE HOTTER IT GETS.
-GROUNDS ARE WATERED ONCE A DAY, GENERALLY IN THE MIDAFTERNOON, WHEN THE SUN AND TEMPERATURES ARE AT THEIR PEAK.
-TEMPERATURE IS NOT THE ONLY PROBLEM. THE WATER’S CHEMICAL COMPOSITION PLAYS A ROLE.
-SOUTHWESTERN GROUNDWATER IS HIGH IN DISSOLVED MINERALS, SUCH AS IRON, WHICH CAN STRAIN, AND CALCIUM, WHICH CAN LEAVE DEPOSITS.
FE: IRON (26)
CA: CALCIUM (20)
MG: MAGNESIUM (12)
SI: SILICON (14)
S: SULFUR (16)
-AS THE WATER EVAPORATES, THESE MINERALS ARE LEFT BEHIND ON THE GRAVESTONE’S SURFACES, OVER TIME FORMING A SKIN.
-AVOIDING THIS BUILDUP REQUIRES REGULAR, CAREFUL CLEANINGS, BUT THERE AREN’T ENOUGH VOLUNTEERS TO CLEAN EVERY HEADSTONE.
-WATERING IN THE EARLY MORNING WHILE GRAVES ARE STILL COOL CAN MINIMIZE MINERAL DEPOSITION AND PREVENT THERMAL SHOCK EVEN BETTER, KEEPING TO NATIVE LANDSCAPING IS A SURE WAY TO PRESERVE THE PIECES OF AMERICA’S HISTORY AMONG THE HEADSTONES FOR GENERATIONS TO COME.

SOURCE: NATIONAL CENTER FOR PRESERVATION TECHNOLOGY AND TRAINING, NATIONAL PARK SERVICE

National Center for Preservation Technology and Training
645 University Parkway
Natchitoches, LA 71457

Email: ncptt[at]nps.gov
Phone: (318) 356-7444
Fax: (318) 356-9119