Dolostone

Dolostone is estimated to be from the Cambrian period,
(500 million years ago).
A carbonate sedimentary rock of which more than 50% by weight or by areal percentages under the microscope consists of the mineral dolomite.

The area here has many examples of Dolostone.
the best example is the Ledger Formation at the posted coordinates.


Dolostone is a sedimentary rock in the class known as chemical sedimentary rocks. It is closely related to limestone, but includes magnesium in the form of calcium-magnesium carbonate. The main constituent is the mineral dolomite. The main pathway to the formation of dolostone is thought to be the replacement of some of the calcium in limestone with magnesium. Dolostone deposits are mainly ancient rocks, giving time for the replacement process in limestone. 

The Ledger Formation is one of the more easily recognized bedrock units throughout the area. This dolomitic unit has been and continues to be a prime target for mining, as confirmed by large and small quarries located throughout the area.
The Ledger is a very light gray to medium-light-gray to light-olive-gray or a pinkish- to light-brownish-gray, fine- to medium-crystalline dolostone. On fresh exposures, the beds are typically devoid (missing) of sedimentary structures, being at best faintly laminated. Laminations can be best observed on weathered bedrock surfaces. Some laminations are thin and regularly spaced and can expand into small (less than 3 cm) gently sloping mounds suggesting they may be algal in origin. No invertebrate fossils have been observed. Meaning no fossils have been found.
Planar partings combine to make it difficult to differentiate joints from bedding. As problematic as this trait may be, it is a very useful field criteria for identifying the Ledger.  Micaceous laminar partings are present but are not typical. Interbeds of medium-gray,  argillaceous dolostone have also been observed.

The uniqueness of this particular example is that it is so easily accessible and its massive size makes it easily distinguishable from the SRT bike trail.

Uses

Limestone and dolomite are major sources of
mineral raw materials for the construction, agricultural, and manufacturing industries of the Commonwealth. Except for coal, carbonates are the major rock type mined in Pennsylvania, accounting for about 80 percent of all nonfuel mineral production.
Significant uses of mined limestone and dolomite in Pennsylvania include
(1) crushed stone for roads, concrete, and railroads; 
(2) agricultural lime and grit;
(3) the manufacture of cement; 
(4) fluxstone and refractory materials for the steel industry; 
(5) acid neutralization; 
(6) raw material for the glass industry; and 
(7) mineral fillers and whiting. Thus, the carbonates in various parts of Pennsylvania should be recognized as a valuable mineral resource, and land use planners should take this into account.  
In horticulture, dolomite and dolomitic limestone are added to soils and soilless potting mixes as a pH buffer and as a magnesium source. Home and container gardening are common examples of this use.
 
Dolomite is also used as the  substrate in marine (saltwater) aquariums to help buffer changes in pH of the water.
 
Particle physics researchers like to build particle detectors under layers of dolomite to enable the detectors to detect the highest possible number of exotic particles. Because dolomite contains relatively minor quantities of radioactive materials, it can insulate against interference from cosmic rays without adding to background radiation levels.

• At what angle is the formation?
• What is the texture of the formation/rock? rough, smooth, glassy, chalky, etc.?
• what geometric shape does it resemble?
• What are some uses of Dolostone in today's society?
• What conclusions of the area can you draw from your observations?

NOTE: I will not respond to answer submissions unless there is an issue. Thank You for Visiting