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Sandstone Showdown


Submitted by drkodos on 2004-03-07

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Sandstone: Is it sand or is it stone?



It is not sand, nor is it stone.

It is sand, frozen in time, pretending to be stone.

I am sure that sounds like weird pseudo-science mumbo-jumbo and is a tough cookie to wrap one’s brain around, but a sort-of-factoid nonetheless. Anyone familiar with the South Philadelphia Italian Frozen desert Water Ice knows the enigma well. It is neither of the things that it is made of, but at the same time a little bit of both, but in a way that makes a delicious new form of matter to be enjoyed.

How can sandstone not be the very best rock for climbers?

Technically speaking, sandstone is: any stone that is an agglutonation of grains of sand, whether calcareous, siliceous, or of any other mineral nature. Siliceous sandstones are the most common, varying in compactness from scarcely cemented sand to a hardness approaching that of quartz rock. The grains are cemented together by silica, lime, etc.



Sandstone, by its very nature, has the widest variety of formations and compactness (hardness) of any rock type. From the crumbly, hardened mud of the Fisher Towers in Utah to the bullet hard Nuttall Sandstone at the New River Gorge, there is a wide and disparate chasm between the two ends of the sandstone spectrum.

Here is why sandstone is clearly the best rock for climbers:

Granite has its geeks, but nobody drives for days to climb a granite chosspile. People come from all over to climb the Fisher Towers, Wall Street, and the Moab area in general. Even the lousiest sandstone is world famous and inspires the boldest climbers.

No other rock allows such a variegated weathering and erosion facade with which to work. Limestone, another sedimentary rock, as varied as it is, tends to produce thematic holds, moves, and protection (none!)

Sandstone has the ability to mimic any other rock form. It is the chameleon of the geologic world. No other rock is as mistaken for so many other types of rock as is sandstone. From the conglomerates at the Gunks, to the gritstone at Stanage Edge, more people mistake sandstone for something else than any other rock.

Another interesting feature of sandstone is also embedded in its geologic nature. As its name openly suggests, sandstone is not quite stone.

Every piece of sandstone has a remarkable and fantastic history to tell and has taken roadtrips beyond anything most climbers could ever envision. Sandstone is rock that has been other rock that has become tiny little rocks and then have been eroded and transported and turned into grains of sand, then subjected to all types of suffocation and oppression only to be remade and revealed once again as a different type of rock and to start the whole rock cycle process again. Some sandstone has been sand and then stone, then sand, then stone, and back and forth again many times throughout the passing ages. This process alone makes sandstone the most interesting to climb upon. Sandstone is the most interesting, the most varied and the best.



The only problem to be solved, then, is what is the best sandstone. To this problem I lend my services. I will endeavor to provide a thorough and well-documented answer. I will make the sacrifice, answer the call of duty and climb as much sandstone as possible in as many areas as possible and quantify every last bit of it in as subjective a fashion as climbing dictates.

In order to do so, first we will take an in depth and scientific look into the world that is sandstone. As climbers we all too often group together and categorize all types of sub-genres yet many never take the time to learn about the medium that makes everything they do possible.

The Science of Sandstone

Sandstone is a name given to rocks in which sand-size grains predominate. It is a member of a larger class of rocks called sedimentary.

Sedimentary rocks account for about 75 percent of all the Earths surface rock outcroppings (1). Erosional agents such as running water, waves, wind and ice remove particles of all types of rocks, igneous, metamorphic, and sedimentary, and move them to a new location. These pieces are often broken down further throughout this process. Following deposition, this new material is called sediment. Over long periods of time, cementation and compaction transform the new material into solid sedimentary rock.

Many sedimentary rocks are important economically. Coal is a sedimentary rock, and many natural resources such as petroleum and natural gas are found in association with sedimentary rocks.

There are two types of sedimentary rocks:

Detrital Sedimentary Rocks & Chemical Sedimentary Rocks

Since sandstone is a detrital type of sedimentary rock we will talk about chemical first.

Chemical Sedimentary Rocks:

Chemical sedimentary tray rocks are formed when the sediment source is a soluble material that is produced by chemical weathering. When substances are precipitated by inorganic or organic processes the material is known as chemical sediment. Limestone is a chemical sedimentary rock. So are dolomite, chert, and many of the evaporates, such as gypsum.



Detrital Sedimentary Rocks:

Particle size is the primary basis for distinguishing among the various detrital sedimentary rocks. The size all of particles is not only a convenient way of dividing the types of rocks but the size of the greens also provides useful information about the environment in which the rock was formed. Currents of water or air sort the particles by size. The stronger the current the larger the particle size carried. Gravels are moved by swiftly flowing rivers as well as by landslides and glaciers. Less energy is required to transport sand and thus it is common to such features as windblown dunes, as well as for some river deposits and beaches. Because clay settles so slowly, accumulations of these tiny grains are generally associated with the quiet waters of a lake, lagoon, certain marine environments.

Shale:

Shale is a rock consisting of silt and clay sized particles. It is common to apply the name of shale to all the fine grained sedimentary rocks, however in the our scientific use of the term to shale must have the ability to split into thin layers along well developed and closely spaced planes if the rock breaks into trunks or blocks the name mudstone is applied another fine-grained rock which like mudstone is often grouped with shale is siltstone. As the name implies siltstone is composed mostly of silt particles and contains less clay and shale and mudstone.

Shale beds do not usually form striking cliffs and prominent outcroppings. Many shales serve as a basic or raw material for pottery, bricks, ceramic tiles, and when mixed with limestone, shale is used to make Portland cement.

Conglomerates:

Conglomerates consistent largely of gravels. These particles they range in size from large boulders to particles as small as garden peas. The particles are commonly large enough to be identified as distinctive rock types, thus they can be valuable in identifying the source areas of sediments. More often than not conglomerates are poorly sorted because the openings between large gravel contain sand or mud.

As with many other sedimentary rocks conglomerates contained clues to their history. Their particle sizes revealed the strength of the currents that transported and the degree of rounding on each particle indicates how for the particles traveled. The fragments within a sample identify the source rocks that supply the particles.

Two of the more well-known conglomerate rock climbing areas in the United States are the Shawangunks (Gunks) in New York and Maple Canyon in Utah.

Sandstones:

Sandstone is the name given to rocks in which sand size grains predominate. Sandstones form in a variety of environments and often contain significant clues about their origins. Sorting is one result of the movement of sediment transported by turbulent air or water. Sorting is the degree of similarity in particle size in a sedimentary rock. By looking at the degree of sorting the kind of depositing materials can be determined. Deposits by windblown sand are usually better sorted than deposits sorted by wave activity and particles washed by waves are commonly better sorted than materials deposit by streams. Accumulations of sentiments that exhibit poor sorting are usually the results of the particles being transported for only a relatively short time and then rapidly deposited. The mineral composition of sentiment will also provide clues to the length of transport.

Because quartz is very durable it is usually the mineral that survives the long trip and turbulent environment. And due to its durability quartz is the predominant mineral in most sandstone. When this is the case the rock is often called quartz sandstone. When the sandstone contains appreciable quantities of feldspar the rock is called arkose.

Back to Climbing

OK, enough of all this scientific techno talk. Let us get back to what this piece is really all about and that's climbing the rocks themselves, and then deciding which ones are the best to climb on. It is important though, before we could go and get subjective by adding our emotions to the fray, to define terminology and scientific understanding, and set down the parameters we will be using over the course of this extensive study.

Another reason why scientific understanding of rock formation is important is because it determines the type of holds that are formed for climbers to use. Many rock types have a limited menu from which to choose when it comes to a holds, cracks, protrusions or other weaknesses from which to achieve suitable purchase for free climbing. Because of the nature of its formation and the wide variety of original rock sources which serve to make up sandstone, a greater variety of holds are available for climbers to choose from.

We will see that the beauty of sandstone climbing, and what makes it superior to any other single type of rock scaling, is not only that one can pick and choose what type of holds they prefer, what type of movement, what type of work-out, and customize their climbing needs by selecting the best type of rock for their purpose. But that sandstone itself is infinitely more fascinating, more varied, more of everything that a climber could want in a rock than any other rock.

The sedimental journey begins.
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