This EarthCache is located at the Museum of Nebraska Art (MONA) which was the original U.S. Post Office in Kearney NE. To claim this EarthCache you must visit the museum during the posted hours of operation. There is no entrance fee required. The location for this EarthCache is in the Lobby of the main entrance as well as the exterior. There are other geological features on the exterior of MONA which will be used to compare to the MARBLE located in the lobby. There are two examples of MARBLE in the lobby. You will learn about a type of Metamorphic Rock: Marble, and be able to distinguish Metamorphic Rock from Igneous and Sedimentary Rock.
Permission has been granted by MONA for placement of this EarthCache. Please sign the guest book when entering the Lobby of the museum.
REQUIREMENTS:
Email your answers to me to verify your smiley. Do not post your answers with your log.
1) Read the text for this EarthCache carefully for answers and information necessary to complete this cache.
2) Respect the site and let the receptionist at the desk know you are EarthCaching. Sign the register. You can sign with your real name or your Geocaching Name.
3) Describe the pattern of marble on the floor of the lobby.
4) Describe the marble on the walls. Describe the coloration of this marble.
5) Are the steps leading to the front entrance made of: Igneous or Sedimentary Rock?
6) On the Exterior of the Building, distinguish between the lower (basement) stone, and the stone above that. Which is granite and which is Sandstone?
7) How does the appearance of the granite (Igneous) and sandstone (Sedimentary) compare to the Marble (Metamorphic) you saw in the lobby of MONA.
8) Enjoy MONA. Optional: Take your picture on the steps of MONA and post to the gallery.
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METAMORPHIC ROCK #1 VERMONT MARBLE
THE INTERIOR WALLS OF THE LOBBY OF THE MUSEUM OF NEBRASKA ART ARE CLAD IN WHITE VERMONT MABLE.
Marble, a metamorphic rock composed principally of calcite, is found in western Vermont. The marble in Vermont was formed by the metamorphism of Cambrian to Ordovician age limestones. Marble from Vermont's Danby quarry has been used in famous buildings such as the Thomas Jefferson Memorial in Washington, D.C., the United Nations Building in New York, and the Chiang Kai-Shek Memorial in Taiwan.
Much of the Vermont marble industry is located within the Champlain Valley and Vermont Valley physiographic province. The Valleys are composed of the shallow marine Cambro-Ordovician shelf sequence, deformed by Taconian folding and faulting. Carbonate sediments have been altered into low-grade marbles, and tight folding has thickened the limbs of associated folds, significantly increasing the size of the ore deposits.
White marble deposits of the Columbian member of the Ordovician Shelburne Formation are located on the western limb of the Middlebury Synclinorium. Next to Italy’s Carrara districts, they yielded the world’s greatest volume of dimension marble. The marble beds are gently to steeply dipping as one moves northward along strike. In the Dorset area, in the southern part of the synclinorium, the beds are relatively flat-lying. Further north, along strike, an “s” fold structure has thickened the beds, providing the location for the Danby Imperial quarry, which has been in operation since 1903.
METAMORPHIC ROCK #2 SIENA MARBLE
THE FLOORS OF THE LOBBY OF MONA ARE COMPOSED OF TERRAZZO WITH WHITE AND SIENNA MARBLE woven in a pattern with Tennessee granite.
Sienna Marble comes from Siena in Tuscany, Italy. It is known for its yellow with violet, red, blue, or white veins. The marble from Tuscany is from the Apennines Mountains. The Apennines were created in the Apennine orogeny beginning in the early Neogene (about 20 mya, the middle Miocene) and continuing today. Geographically they are partially or appear to be continuous with the Alpine System.
This marble is a rock resulting from metamorphism of sedimentary carbonate rocks, , most commonly limestone or dolomite rock. Metamorphism causes variable recrystallization of the original carbonate mineral grains. The resulting marble rock is typically composed of an interlocking mosaic of carbonate crystals. Primary sedimentary textures and structures of the original carbonate rock (protolith) have typically been modified or destroyed.
Pure white marble is the result of metamorphism of a very pure (silicate-poor) limestone or dolomite protolith. The characteristic swirls and veins of many colored marble varieties are usually due to various mineral impurities such as clay, silt, sand, iron oxides, or chert which were originally present as grains or layers in the limestone. Green coloration is often due to serpentine resulting from originally high magnesium limestone or dolostone with silica impurities. These various impurities have been mobilized and recrystallized by the intense pressure and heat of the metamorphism.
Marbles may be variously colored or banded, depending on their chemical and mineralogical compostion (mostly Calcite), e.g. Carrara marble is pure white but Siena marble, quarried in Tuscany, has red mottling. MARBLE is a Metamorphic Rock.
COMPARISON OF ROCKS
Rocks are classified as Igneous, Sedimentary and Metamorphic.
Igneous rocks are formed from the solidification of molten rock material. There are two basic types: 1) intrusive igneous rocks such as diorite, gabbro, granite and pegmatite that solidify below Earth's surface; and 2) extrusive igneous rocks such as andesite, basalt, obsidian, pumice, rhyolite and scoria that solidify on or above Earth's surface.
Sedimentary rocks are formed by the accumulation of sediments. There are three basic types of sedimentary rocks: 1) clastic sedimentary rocks such as breccia, conglomerate, sandstone and shale, that are formed from mechanical weathering debris; 2) chemical sedimentary rocks such as rock salt and some limestones, that form when dissolved materials precipitate from solution; and, 3) organic sedimentary rocks such as coal and some limestones which form from the accumulation of plant or animal debris.
Metamorphic rocks have been modified by heat, pressure and chemical process usually while buried deep below Earth's surface. Exposure to these extreme conditions has altered the mineralogy, texture and chemical composition of the rocks. There are two basic types of metamorphic rocks: 1) foliated metamorphic rocks such as gneiss, phyllite, schist and slate which have a layered or banded appearance that is produced by exposure to heat and directed pressure; and, 2) non-foliated metamorphic rocks such as marble and quartzite which do not have a layered or banded appearance.
MONA
Completed in 1911, the Kearney Post Office’s exterior construction includes a foundation of New Hampshire granite and a façade featuring Tuscan columns made of Bedford Limestone. The style of the building is classic, with Corinthian details and touches of Italian Renaissance. The basement walls above ground are of New Hampshire granite, and above these the walls are of Bedford sandstone.
MONA is located at 2401 Central Avenue Kearney, NE 68847. Phone: (308) 865-8559
Hours: Tue. - Sat.: 11 a.m. - 5 p.m. / Sun.: 1 - 5 p.m. / Closed Mondays and major holidays. MONA is handicapped accessible.
REFERENCES
A Dictionary of geology and Earth Sciences, pp 358-359. “Marble”
http://geology.com/rocks/igneous-rocks.shtml
http://www.bchs.us/WalkingTourBookletrevisied61813.pdf
http://en.wikipedia.org/wiki/Apennine_Mountains
http://en.wikipedia.org/wiki/Red_Verona_marble
http://en.wikipedia.org/wiki/Marble
http://www.anr.state.vt.us/dec/geo/staterx.htm
http://mona.unk.edu/mona/about.html
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