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Norcross Quarry, Dorset, Vermont.

Rock to Stone — Assignment

Terms

Aggregate. Any of several hard, inert materials, such as sand, gravel, slag, or crushed stone, used for mixing with a cementing or bituminous material to form concrete, mortar, or plaster; or used alone, as in railroad ballast or graded fill.

Bed. The smallest lithostratigraphic unit, commonly ranging in thickness from a centimeter to a meter or two and distinguishable from beds above and below. The term is generally applied to sedimentary strata, but it may also be used for other types, as an ash bed.

Formation. A body of rock strata that consists dominantly of certain lithologic type or combination of types. Formations may be combined into groups or subdivided into members.

Hand specimen. A piece of rock trimmed to a convient size for megascopic study and for preservation in a reference or study collection.

Lithology. The description of rocks, esp. in hand specimen and in outcrop, on the basis of such characteristics as color, mineralogic composition, and grain size. The physical character of a rock.

Petrography. That branch of geology dealing with the description and systematic classification of rocks, esp. igneous and metamorphic rocks and esp. by means of microscopic examination of thin sections. Petrography is more restricted in scope than petrology.

Petrology. That branch of geology dealing with the origin, occurence, structure, and history of rocks, esp. igneous and metamorphic rocks. Petrology is broader in scope than petrography.

Regolith. The fragmental and unconsolidated rock material, whether residual or transported, that nearly everywhere forms the surface of the land and overlies the bedrock. It includes rock debris of all kinds -- volcanic ash, glacial drift, alluvium, loess, vegetal accumulations, and soil.

Rock. An aggregate of one or more minerals, e.g. granite, shale, marble; or a body of unifferentialted mineral matter, eg. obsidian, or of solid organic material, e.g. coal.

Sedimentary petrology. The description and clasification of sedimentary rocks.

Soil. In engineering geology, all unconsolidated materials above bedrock, i.e. the regolith.

Stone. A general term for rock that is use in construction, either crushed for use as aggregate or cut into shaped bocks as dimensional stone.

Structure. A feature produced by deformation or displacement of the rocks, such as a fold or fault.

Introduction

Undertake a brief visual survey of masonry buildings to determine what local stone (or aggregate, regolith, soil) was/is employed in the area's buildings.

Use of the dimensional stone may range from random rubble or roughly coursed ashlar for foundations; to trimwork for splash courses, window and door openings, and steps; to entire exterior walls ranging from random rubble to coursed ashlar; to roofing slate – and many other applications.

The stone may be any rock type: igneous, metamorphic or sedimentary. Or you may select sediments, aggregate, products from the regolith used in building construction.

Building Stone, Initial Research

1. Identify site/building by (historic) name, address, date of construction (and changess), architect and builder, and other historical information. Note if building is listed on the National Register as an individual site or as part of a district.
2. Write a brief (one paragraph) architectural description of the structure. If the National Register (or state survey) description is available, use and cite this resource, or others.
3. In detail, describe the characteristics of the stone as it is employed for architectural purposes. Note: elements employing the stone; dimensions of stock; quarrying and finishing techniques indicated by toolwork; appearance; condition (noting ways in which the material may be failing); architectural and physical relation with overall design intent and construction – in relation to other materials, design.
4. Look around the neighborhood, town to see what other buildings employ the same stone. Talk to people in the community: local historians, craftspeople, monument dealers (who see stone monumental stone from all over the world, but who may still know a lot about historic stone industries in the area). Is there a "Quarry Steet," "Furnace Street," or "Kiln Street," leading to historic industries?
5. Look for local historic maps (Wallings, Beers, Sanborn) indicating quarries; postcards, photographs; surveys; other resources. Reference citations, images, other sources.
6. Consider mid-19th-century state geological surveys (typically one volume); late 19th- and early 20th-century state geological publications (annual; special, industry-specific issues; maps of statewide surveys); U.S.G.S maps, historic annual reports, special reports.
7. Photograph (4"x6" color prints, or digital equivalent) an example of the use(s) of the building stone in a structure. Provide overview of site, building, and details. Use scale in images.

Rock

1. Reference research under "Building Stone."
2. Locate a (the) source rock for the building stone and obtain a sample. This may be a quarry, an outcrop, or roadcut that exhibits a similar rock type to that which was quarried and used.
3. Identify the location on a USGS topographic map, or download a digital image of the map, citing the source and topographic quadrant sheet. Photocopy, lasercopy or scan hard copy. Employ GPS coordinates if you wish. Include goeological maps, if possible.
4. Describe the gross geological, structural characteristics of the rock as it is exposed. Note: petrology and lithology; beds (if present); structure (folding, faulting, fracturing. etc.); weathering and erosion; other factors affecting its appearance and condition.
5. Describe, as much as possible, the rock type – its lithologic, petrologic characteristics and composition. If possible note geologic formation with group, member if indicated) reference geological maps or other published references. You may use, and cite, the published geologic description of the formation, lithology, and other characteristics. Reference pertinent scientific literature and sources.
6. If applicable, note quarrying operations.
7. Photograph the rock source, employing a scale in all photographs.
8. Obtain a hand specimen (sample) that represents the typical characteristics of the formation. If necessary, obtain more than one sample. Shape sample on site so it exhibits a weathered surface and freshly exposed surface. Provide a label noting location, collector, date.

Note! You will likely need a geologic or mason's hammer to obtain a sample. Wear protective eyewear whenever obtaining samples. Keep away from high and steep faces of rock (quarries, roadcuts, etc.), especially in the springtime as weathering during the winter may cause rocks to fall – on you.

Report

• Prepare a report along with photographs, photocopies (or lasercopies, digital images) of geological or topographic map, historical materials and maps, and rock sample, with geological and topographical identification. Hand in as hard copy and in digital form.

Presentation

• Bring in report and rock sample(s) for class examination and discussion.