The Plague Column
The purpose of this EarthCache is to introduce you to the basics of sandstone.
Sandstone is a sedimentary rock composed of sand-size grains of mineral, rock, or organic material. It also contains a cementing material that binds the sand grains together and may contain a matrix of silt- or clay-size particles that occupy the spaces between the sand grains.
Sandstone is one of the most common types of sedimentary rock and is found in sedimentary basins throughout the world. It is often mined for use as a construction material or as a raw material used in manufacturing. In the subsurface, sandstone often serves as an aquifer for groundwater or as a reservoir for oil and natural gas.
Weathering and Transport of Sand
The grains of sand in a sandstone are usually particles of mineral, rock, or organic material that have been reduced to "sand" size by weathering and transported to their depositional site by the action of moving water, wind, or ice. Their time and distance of transport may be brief or significant, and during that journey the grains are acted upon by chemical and physical weathering.
Types of Sand Grains
The percentage of grains in the sandstone depends upon their source and how they have suffered during transport.
Mineral grains in sandstones are usually quartz. Sometimes the quartz content of these sands can be very high - up to 90% or more. These are sands that have been worked and reworked by wind or water and are said to be "mature." Other sands can contain significant amounts of feldspar, and if they came from a source rock with a significant quartz content they are said to be "immature."
Uses
Sandstone was a popular building material from ancient times. It is relatively soft, making it easy to carve. It has been widely used around the world in constructing temples, homes, and other buildings. It has also been used for artistic purposes to create ornamental fountains and statues.
Some sandstones are very resistant to weathering, yet are easy to work. This makes sandstone a common building and paving material including in asphalt concrete.
If the sand is deposited close to its source rock, it will resemble the source rock in composition. However, the more time and distance that separate the source rock from the sand deposit, the greater its composition will change during transport. Grains that are composed of easily-weathered materials will be modified, and grains that are physically weak will be reduced in size or destroyed.
Questions:
1. What type of modern aging do you observe the stone has succumbed to?
2. What is the texture of the stone, does it feel durable?
3. Name one mineral grain that can be found in the composition of sandstone.
4. There is a statue pierced by arrows, how many arrows are there?
Dont wait for approval, send me the answer and log it as usual, if there's something wrong I will get back to you.
Coloana Ciumei
Scopul acestui EarthCache este de a prezenta elementele de baza ale gresiei.
Gresia este o roca sedimentara compusa din granule de marimea nisipului din minerale, roci sau materiale organice. De asemenea, contine un material de cimentare care leaga granulele intre ele si poate include particule de aluviuni sau argila, care ocupa spatiile dintre granule.
Gresia este unul dintre cele mai frecvente tipuri de roca sedimentara si se gaseste in bazinele sedimentare din intreaga lume. Adesea este extrasa pentru a fi folosita ca material de constructie sau ca materie prima folosita in industrie. I n subteran, gresia serveste adesea ca acvifer pentru apele subterane sau ca rezervor pentru petrol si gaze naturale.
Interperii si transportul nisipului
Granulele de nisip dintr-o gresie sunt de obicei particule de minerale, roca sau materiae organice care au fost reduse la dimensiunea „nisipului” prin intemperii si transportate la locul lor de depozitare prin actiunea miscarii apei, vantului sau ghetii. Timpul și distanta lor de transport pot fi scurte sau semnificative, iar in timpul acestei calatorii, boabele sunt afectate de intemperii chimice si fizice.
If the sand is deposited close to its source rock, it will resemble the source rock in composition. However, the more time and distance that separate the source rock from the sand deposit, the greater its composition will change during transport. Grains that are composed of easily-weathered materials will be modified, and grains that are physically weak will be reduced in size or destroyed.
Daca nisipul este depus aproape de roca sursa, acesta va semana cu roca sursa in compozitie. Daca roca sursa este separata de zacamantul de nisip mult timp si cat mai departe, compozitia sa se va schimba foarte mult in timpul transportului. Granulele care sunt compuse din materiale ce pot fi modificate usor de intemperii vor fi modificate, iar granulele foarte slabe din punct de vedere fizic vor fi reduse ca marime sau distruse.
Tipuri de granule de nisip
Cantitatea de granule din gresie depinde de sursa lor si cat au avut de suferit in timpul transportului.
Granulele de minerale din gresie sunt formate de obicei din cuart. Uneori, continutul de cuart al acestor nisipuri poate fi foarte mare - pana la 90% sau mai mult. Este vorba despre nisipuri care au fost lucrate și relucrate de vant sau apa si despre care se spune ca sunt „mature”. Alte nisipuri pot contine cantitati semnificative de feldspat si, daca provin dintr-o roca sursa cu un continut semnificativ de cuart, se spune ca sunt „imature”.
Utilizari
Gresia a fost un tip de piatra popular in constructii inca din Antichitate. Este o piatra relativ moale, ceea ce o face usor de modelat. A fost folosita in toata lumea la constructia de temple, case si alte cladiri. A fost folosita si pentru realizarea de statui sau fantani.
Unele gresii sunt foarte rezistente la intermperii, si cu toate acestea usor de modelat. Acest lucru face gresia un material numai bun de folosit in pavare sau in continutul betonului asfaltic.
Some sandstones are very resistant to weathering, yet are easy to work. This makes sandstone a common building and paving material including in asphalt concrete.
Intrebari:
1. La ce fel de intemperie "moderna" observati ca este supus monumentul?
2. Ce fel de textura are piatra, este durabila?
3. Numiti un tip de mineral ce intra in componenta gresiei.
4. O statuie este strapunsa de mai multe sageti. Cate se pot vedea?
Nu asteptati pentru aprobare, trimiteti raspunsurile si logati, daca e ceva in neregula va contactez.