Photography, rowing and the pursuit of data.....and Renee  

Scenery is created by the deposition of rocks, the uplift of rocks, and the erosion of rocks. It is then modified by the vegetation that the  land supports.  Scenery can be broadly classified by the underlying geology all based on silicate chemistry of magma, biomaterials, erosion to form sandstone, extreme pressure and thermal processes, and hydrothermal concentration. ​

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Deposited as 

• Volcanic rock

• Sandstone

• Biomaterials - a significant source of chemical change and concentration in rocks

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Processed by plate tectonics

• Subducted to form  Metamorphic rock

• Chemical conversion by chemical reactions  

• Physical conversion by hydrothermal recrystallization, and temperature/pressure densification. 

• Uplifted to expose to weathering 

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Eroded by 

• Fresh water 

• Ice

• Oceans

• Meteors

• Volcanic explosions

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Leaving bare rock unless overgrown by 

• Evergreen forest

• Deciduous forest

• Tropical forest 

• Grassland 

• Ice

• Redeposited sand as beaches and silt ​

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Today's scenery is the latest snap shot of the  accumulation of multiple cycles of uplift and removal, dominated by the partial erosion of the last uplift. The erosion is mostly caused by liquid water creating "V shaped" valleys often following fault lines, and cliffs at the ocean. Glacier ice erodes creating "U- shaped" valleys. Secondary sources of erosion are wind, meteor impact, volcanic explosion. Where there is water, vegetation overgrows the rock. 

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Plate tectonics is the engine of change in our scenery. Volcanic activity leads to magma forming real time land growth mostly along plate boundaries such as the Cascades on the  "Ring of Fire" and at stationary hot spots such as Hawaii and Galapagos. The plate structure and hot spots are thought to be caused by thermal and chemical non-uniformities in the lower mantle a 200 km layer above the core. They have been mapped as "Large low-shear-velocity provinces" using seismic tomography https://en.wikipedia.org/wiki/Large_low-shear-velocity_provinces.

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Sandstone is created from erosion debris settling out of the water. Uplift of sandstone from plate motion creates dry land that is then subject to water erosion to create places such as Zion, Grand Canyon and the Canadian Rockies. 

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Motion at plate boundaries also drive sandstone down towards the molten core. High pressure and temperature, and injections of magma causes chemical changes in sandstone to create metamorphic rock. Subsequent uplift from plate motion exposes the rock to erosion.  The youngest mountains such as the Sierras were uplifted 6-5My ago. The Himalayas and Rockies were uplifted  60My-40My ago. The Appalachians were uplifted 300My ago during the creation of Pangea. 

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The oldest rocks that are visible today are 4500My ago in western Australia, because Australia is in relative tectonic isolation. 

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Deposition

Igneous

Igneous rocks are formed through the cooling and solidification of magma or lava. ​Most magma is rich in silica, and crystallize as quartz (silicon dioxide) and complex "tectosilicates" with a variety of cations. The melt crystallization of magma naturally separates into a mixture of different crystal minerals, the slower the cooling the larger the crystals. Rare nonsilicate magma can form by local melting of nonsilicate mineral deposits or by separation of a magma into separate immiscible silicate and nonsilicate liquid phases.  ​

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Silicate magmas are molten mixtures characterized by oxide contents. Silicon oxides, the most abundant chemical elements in the Earth's crust, with smaller quantities of   oxides of aluminium, calcium, magnesium, iron, sodium, and potassium, and minor amounts of many other elements.    https://geo.libretexts.org/Bookshelves/Geology/Mineralogy_(Perkins_et_al.)/06%3A_Igneous_Rocks_and_Silicate_Minerals/6.02%3A_Compositions_of_Igneous_Rocks/6.2.01%3A_Mafic_and_Silicic_Magmas

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Most magmas contain liquid mineral mixtures,  fragments of exotic rocks known as xenoliths and fragments of previously solidified magma. The crystal content of most magmas gives them thixotropic and shear thinning properties.[48] In other words, most magmas do not behave like Newtonian fluids, in which the rate of flow is proportional to the shear stress. Instead, a typical magma is a Bingham fluid, which shows considerable resistance to flow until a stress threshold, called the yield stress, is crossed.

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The most common igneous rock is fine grained "Basalt", a low viscosity, low silica content material "mafic" from the magma  core.  Creates thin planes of flowing lava as seen in Iceland and Hawaii. Slow cooling magma can form hexagonal pillars such as "Devils postpile". Granite is igneous inclusions that have cooled as they are injected into metamorphic rock.  Gabbro is slow cooled large grained "mafic" basalt. Basalt is composed mostly of quartz, and complex "tectosilicates" of sodium, potassium, iron and magnesium.  

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Rhyolite is an extrusive igneous rock, formed from magma rich in silica that is extruded from a volcanic vent to cool quickly on the surface rather than slowly in the subsurface. It is generally light in color due to its low content of mafic (Mg and Fe) minerals, and it is typically very fine-grained (aphanitic) or glassy. 

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Obsidian  is a naturally occurring volcanic glass formed when lava extruded from a volcano cools rapidly with minimal crystal growth.   Produced from felsic lava, obsidian is rich in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium.  Obsidian is hard, brittle, and amorphous; it therefore fractures with sharp edges. In the past, it was used to manufacture cutting and piercing tools, and it has been used experimentally as surgical scalpel blades.

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In a couple of locations on the planet, Great Lakes is one, high copper containing magma has resulted in the accumulation of pure copper crystals in basalt fissures. This is possibly associated with very low Sulphur content magmas, avoiding the formation of sulphides. Copper is one of the few pure naturally occurring metals. 

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While the first iron ore was likely meteoric iron, and hematite was far easier to smelt, in Africa, where the first evidence of iron metallurgy occurs, limonite is the most prevalent iron ore.

• Limonite is a form of hydrated iron oxide. It is found as a host for many metals including gold and nickel

• Hematite  is a common iron oxide compound with the formula Fe2O3 and is widely found in rocks and soils.

• Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe2+Fe3+2O4. It is one of the oxides of iron, and is ferrimagnetic.

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Volcanism produces the most recent structures along the fault lines of the tectonic plates. The best examples are all along the "Ring of Fire" around the Pacific Ocean. ​​

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Sandstone 

Sandstones are deposited in layers of eroded rock in shallow seas. Away from the plate boundaries, the sandstone layers remain pristine. These are then uplifted and eroded to produce classic stair step valley walls, The best examples of sandstones are in the layers in the  "Giant Stair Case" that extends from  Arizona to Utah, including Bryce Canyon, Zion, Monument Valley, and  Grand Canyon.

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Most sandstone is composed of quartz (silicon dioxide) or feldspar (aluminum tecto-silicate) because they are the most resistant minerals to the weathering processes at the Earth's surface. If there is  iron in sandstones they turn red after atmospheric oxidation. If the sandstones become water logged, the iron can get washed out producing the white sandstone seen in Zion NP.   When water logged and subjected to deformation they can form all sorts of twisted layers. White Pocket in Utah is a spectacular example. 

Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g., kaolin, Al2Si2O5(OH)4) and tiny fragments (silt-sized particles) of other minerals, especially quartz and calcite.[1] Shale is characterized by its tendency to split into thin layers (laminae) less than one centimeter in thickness produced by  self aligned mineral flakes. This property is called fissility.  Shale is the most common sedimentary rock.[2]​

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Clays are formed by acid weathering of feldspar (aluminum tecto-silicate)-rich rock, such as granite, in warm climates tends to produce kaolin. Chemical weathering  by acid hydrolysis is caused by low concentrations of carbonic acid. The acid breaks bonds between aluminium and oxygen, releasing other metal ions and silica (as a gel of orthosilicic acid).)

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Biomaterials

Biominerals provide an important source of non-magma materials, a significant source of chemical change and concentration in rocks. It is the process by which living organisms produce minerals, often resulting in hardened or stiffened mineralized tissues. It is an extremely widespread phenomenon: all six taxonomic kingdoms contain members that can form minerals, and over 60 different minerals have been identified in organisms. Examples include silicates in algae and diatoms, carbonates in invertebrates, and calcium phosphates and carbonates in vertebrates. These minerals often form structural features such as sea shells and the bone in mammals and birds.

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Limestone is composed mostly of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate CaCO3. Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life. Because of the solubility of limestone in water, caves are often formed with stalagmite and stalactite pillars of redeposited calcium carbonate. 

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Scenery based on hard limestone is often called "Karst" scenery e.g. Islands of Thailand and Raj Ampat in south Asia deposited around 280 Mya in Permian. ​Also Malham Tarn in the UK Peak district  350-300 Mya Carboniferous, and Texas hill country with layers of both Carboniferous and Cretaceous limestones, with dinosaur footprints in the Cretaceous layers. Corals are the calcium carbonate exoskeleton of collections of animals called "polyps". Combinations of 3 different crystal symmetries gives rise to the range of structures. 

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Marl is a compressed mud with high levels of calcium carbonate.

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Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of Phyto-plankton   "coccolithophores" that had settled to the sea floor. The White Cliffs of Dover are a great example from the Mesozoic 250-66Mya. ​

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Chert is typically composed of the petrified remains of siliceous ooze, the biogenic sediment that covers large areas of the deep ocean floor, and which contains the silicon skeletal remains of diatoms, silicoflagellates, and radiolarians.[5] Precambrian cherts are notable for the presence of fossil cyanobacteria. The unique feature of diatoms is that they are surrounded by a cell wall made of silica (hydrated silicon dioxide), called a frustule.

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Flint is a type of Chert or sedimentary cryptocrystalline form of the mineral quartz (SiO2),  categorized as the variety of chert that occurs in chalk or marly limestone as the conditions that encourage coccolithophores also encourage diatoms to thrive. Historically, flint was widely used to make stone tools and start fires, with sharp edges just like broken glass. Flint occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones. One hypothesis is that a gelatinous material "siliceous ooze" fills cavities in the sediment, such as holes bored by crustaceans or molluscs, and that this becomes silicified, all at low temperatures that leave the limestone intact.  ​

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"Diamataceous earth", primarily silicates, is formed from sediments of diatom exoskeleton. Formed more recently, 66-2Mya, in volcanic regions that are a source for soluble silicate.  Used as a filtration aid. 

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Examples of biogenic minerals include:

• Calcium phosphate; 

  • Apatite in bones and teeth

  • Hydroxyapatite formed by mitochondria

• Calcium carbonate

  • Aragonite, calcite, fluorite in vestibular systems (part of the inner ear) of vertebrates

  • Aragonite and calcite in travertine and biogenic silica (siliceous sinter, opal) deposited through algal action

  • Shells, algae exoskeletons

  • Raphides - oxalate (bicarbonate)  needles in some plants, also strontium and barium sulfate [140]

• Iron oxides;

  • Goethite found as filaments in limpet teeth

  • Magnetite and greigite formed by magnetotactic bacteria

• ​Iron sulphides;  Pyrite -fools gold and marcasite in sedimentary rocks deposited by sulfate-reducing bacteria

• Silicon dioxide;  Quartz formed from bacterial action on fossil fuels (gas, oil, coal) in diatoms​​

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Coal is a land based fossil fuel formed when dead plant matter decays into peat which is converted into coal by the heat and pressure of deep burial over millions of years. Vast deposits of coal originate in former wetlands called coal forests that covered much of the Earth's tropical land areas from 300-250 Mya during the late Carboniferous (Pennsylvanian) and Permian times.

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Petroleum is a sea-based  fossil fuel formed over millions of years from anaerobic decay of organic materials from buried prehistoric organisms, particularly planktons and algae. This time frame coincides with the appearance of limestones made from the exo-skeletons of algae and similar. It is estimated that 70% of the world's oil deposits were formed during the 250-66Mya Mesozoic, 20% were formed in the 66-0 Mya Cenozoic, and only 10% were formed in the 550-250 Mya Paleozoic.

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Processed by plate tectonics 

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Subducted to from Metamorphic 

Subduction is paired with uplift at tectonic plate boundaries. The rock is exposed to extreme pressure and thermal cycling which produces physical conversion by  densification,  solubility,  and re-crystallization. There is also significant chemical conversion particularly in  reactions  with super heated water. However the important point is that metamorphic rock retains the layer structure of the original rock. This suggests that there is primarily densification NOT melting. The concentration of minerals comes solution recrystallization.  

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Metamorphic tectonite is a rock in which the fabric elements reflect the history of deformation. Metamorphic rocks started as sandstones. Near plate boundaries, sandstones are driven down and magma injected in at high pressure creating new crystals structures "recrystallization". These rocks are typically much harder and resistant to erosion. As a result Metamorphic rocks form some of the steepest and most majestic mountains. 

• Gneiss is old metamorphic sandstone that is banded but does not form layers 

• Shist is metamorphic sandstone that does form layers caused by recrystallization under pressure. 

• Granofels, uniform and solid showing no obvious foliation or schistosity.

• Slate is  recrystallized Shale sandstone

• Marble is recrystallized limestone. Turkey is largest source, used by European sculptors.

• Plutonic describes metamorphic rock that includes igneous rock formed by solidification of magma at considerable depth beneath the earth's surface.

• Granite is an igneous inclusion in the metamorphic eg. Yosemite in Sierra Nevada  ​

• Flysch consists of repeated sedimentary cycles with uplifted to form upwards oriented  sediments to form vertically deeply layered rock.  They progress from deep-water and turbidity flow deposits to shallow-water shales and sandstones. Flysch typically consists of a sequence of shales (fine grained) rhythmically interbedded with thin, hard, graywacke-like sandstones (coarse crystal/clay).  It is deposited when a deep basin forms rapidly on the continental side of a mountain building episode. Examples are found near the North American Cordillera, the Alps, the Pyrenees and the Carpathians. 

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Water is the principle chemical modifier of deposited rock. Rain water is acidic from absorbed CO2 forming carbonic acid. Acidic water dissolves limestone (calcium carbonate) deposits creating caves, then redeposits forming stalagmites and stalactites.  Hard water in limestone country contains calcium and magnesium carbonates, acids cause carbonates to dissolve, alkali causes  precipitation. Saltwater is basic so limestone islands in "Karst" scenery do not dissolve away.  

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Volcanic hydrothermal sources are often associated with hydrogen sulphide gas and are strongly acidic and corrosive. Quartz deposits are dissolved and then cooled and regrown in cracks or voids (becoming geodes) in rocks. It seems that the most spectacular crystals are grown from solution rather then melt sourced igneous rocks.

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Basic (alkaline) water sources are sea water and ammonia solutions from decomposing vegetation. 

https://www.ebsco.com/research-starters/earth-and-atmospheric-sciences/hydrothermal-solutions-and-mineralization​​​​​​

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The majority of quartz crystallizes from molten magma, quartz also chemically precipitates from hot hydrothermal veins as gangue, sometimes with ore minerals such as gold, silver and copper. Large crystals of quartz are found in magmatic pegmatites. A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than 1 cm (0.4 in) and sometimes greater than 1 meter (3 ft). Most pegmatites are composed of quartz, feldspar (aluminum tectosilicate), and mica (plates of quartz), having a similar silicic composition to granite. However, rarer intermediate composition and mafic pegmatites are known. ​ Quartz also forms in hydrothermal environments, where hot, mineral-rich water flows through cracks in the Earth's crust. As the water cools and evaporates, it leaves behind deposits of quartz, often in the form of stunning, well-formed crystals. These crystals can fill veins in rocks or form in cavities, where there is ample room for the crystals to grow over millennia. These environments are responsible for producing the quartz found in geodes and veins, often with other minerals like gold, pyrite, or even amethyst.

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​The concentration of minor contaminants by differential crystallization combined with  precipitation out of basic or reducing hot water solutions produces veins of gold in quartz crystals. Gold is often found inside quartz veins or associated with it due to its high resistance and its connection to hydrothermal systems. The quartz veins cut through metamorphic mountains such as schist, greenstone, and serpentinite, near old zones affected by heat and mineral-rich fluids (hydrothermal zones) and areas with iron oxides (yellow–brown–red staining), pyrite (Iron disulphide), galena (lead sulphide), and chalcopyrite (copper iron sulphide) near quartz veins.  Gold can be transported as Au(I)–OH−/NH3 complexes in sulfur-poor and ammonia-rich (basic) hydrothermal fluids.

https://www.sciencedirect.com/science/article/abs/pii/S0016703719307884
 

Spectacular examples of banded crystals are formed in chalcedony a cryptocrystalline form of silica, composed of very fine intergrowths of  quartz with a trigonal crystal structure, with moganite which is monoclinic.  Agate is a well known example. Best examples are found in  Geodes which are hollow, vaguely spherical rocks, in which masses of mineral matter (which may include crystals) are secluded. The crystals are formed by the filling of vesicles in volcanic and subvolcanic rocks by minerals deposited from hydrothermal fluids; or by the dissolution of syngenetic concretions and partial filling by the same or other minerals precipitated from water, groundwater, or hydrothermal fluids. The many crystals are seeded at the surface, but as the layer grows, these seeds merge producing larger crystals.  The colorful banding in geodes results from the  changes in composition of the water.  Geodes are found in sedimentary rocks in Utah and Idaho, and also in igneous rocks in S America. 

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Amethyst is a violet variety of quartz (SiO2) and owes its violet color to irradiation, impurities of iron (Fe3+) and in some cases other transition metals, and the presence of other trace elements, which result in complex crystal lattice substitutions.  The continuous exposure to natural gamma radiation from radioactive isotopes, such as potassium-40, present in the surrounding volcanic basalt. causes the iron (Fe+3) ions that replace Si in the lattice to lose an electron and form a [FeO4]0 color center.

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Emerald is beryllium silicate doped with chromium.

Opal is a hydrated amorphous form of silica due to the amorphous (chemical) physical structure, it is classified as a mineraloid, unlike crystalline forms of silica, which are considered minerals. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl, and basalt.

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Sapphire and ruby are doped perfect crystalline aluminum oxide, and with imperfect  crystals in corundum. Corundum occurs as a mineral in metamorphic rocks based on silicates or calcium carbonate. It also occurs in low-silica igneous silicate intrusives. 

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Diamonds, pure crystalline Carbon  is formed with ages between 1 billion and 3.5 billion years. Most were formed at depths between 150 and 250 kM (93 and 155 mi) in the Earth's mantle, although a few have come from as deep as 800 kM (500 mi). Under high pressure and temperature, carbon-containing fluids dissolved various minerals and replaced them with diamonds. Much more recently (hundreds to tens of million years ago), they were carried to the surface in volcanic eruptions and deposited in igneous rocks known as kimberlites and lamproites (low silicate & high magnesium). The pipes or vertical columns were formed by explosive eruptions driven by CO2 and no water. The atmosphere needs to be anoxic (reducing and oxygen free).

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Uplifted 

Uplift associated with tectonic plate boundaries  exposes the metamorphic rock There have been multiple rearrangements of the land masses on earth over the ages. The boundaries between the plates mark the uplift or growth between plates, and are associated with earthquakes and volcanoes.

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The most recent uplifts are:

India with Nepal forming the Himalayas, 

Africa with Europe forming the Alps

Pacific plates with the Americas forming the Sierras and Andes.​​​​​​​

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REMOVAL

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The flow of liquid water is probably makes the single biggest natural impact on our scenery. It flows downhill though any weakness in the rock forming anything from slot canyons to wide V-shaped valleys. In colder climes, ice flows much more slowly but is hard and abrasive. Glaciers from the ice ages 400Ky - 20Ky ago covered roughly half the globe creating U shaped valleys. Today's glaciers are receding due to global warning.  On the coast, ocean waves are another aggressive source of erosion. 

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Volcanic explosions forming craters and calderas, the Yellowstone caldera was one of the larger ones. 

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Meteors forming impact craters, the extreme example is the K/T Meteor that ended the dinosaurs. Some elements represent our galactic ancestors. Gold in the universe is produced through several cosmic processes and was present in the dust from which the Solar System formed.[62] Scientists have identified three main cosmic sources for gold formation: supernova nucleosynthesis, neutron star collisions,[63] and magnetar flares.

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