Where are Precambrian rocks most likely to be exposed at the surface?
479973
There are some famous places where Precambrian rock is exposed such as the Canadian Shield. It spans across Canada & parts of Greenland.\n\nThe basement rock in the Grand Canyon (rock on the bottom) is also visible.\n\nMost Precambrian rock is covered w/ sediment & or sedimentary rock where lowlying areas of it exist.\n\nAnywhere where Precambrian rock has been uplifted is a good place to look. Like the Teton Mtn. Range in Wyoming. That would be your best bet. At the feet of fault block mtn. ranges.
863614
This depends a bit on what we call a "mountain range". However;\nThe big ranges (Andes, Himalaya, Alps etc) are all very young, most uplift in the past 30 million years and much in the past 3-5my\nThe mountain belt including the Scandinavian peninsula, the Scottish Highlands, English Lake District and Wales were part of an "Andean" type range about 400my ago.  The Apalachians in the US are actually part of the same chain, "broken off" so to speak.\n\nSome parts of the Scottish Highlands, in the north west, were formed in the core of a much older range, up to 2,500my, but it is debatable whether you can call that a "mountain range".\n\nThe very ancient granites and gneisses (>4,000my) in Canada, Australia, Southern Africa and Greenland were likewise probably part of a mountain building episode, though the Plate Tectonics that formed later mountains probably hadn't kicked in then.  And these days, those areas are mostly rather level and eroded.  The South Africa/Swaziland border where some of these rocks are found is pretty rugged, but whether you could call it a "mountain range" is again debatable.\n\nPart of the problem is that there are ancient rocks within some very young mountain ranges - the rocks are old but the uplift forming the mountains is recent.\n\nIf we call a mountain range a "linear feature of land with steep and rugged terrain significantly higher than the land either side" , and an old range is one that has always been relatively high, not recently pushed up, then we need to find such a feature made of Pre-Cambrian rocks to meet the definition of "oldest mountain range".\n\nOff the top of my head, I'd plump for parts of the Appalachians.  The main range is "only" a few hundred milion years old, but the Pre-Cambrian blocks within were probably standing as elevated mountain blocks when the plate collision forming the range began.  So there has been an elevated upland in that area for perhaps a billion years.
193598
well, there is the theory of plate tectonics which tells us that the earth's crust is comprised of plates that converge, spread, subduct,  and slide with one another.  This is the main culprit of orogeny, which is mountain building.  Then you have to consider weathering which is performed mainly by wind and water, ie..rivers, lakes, streams, ocean currents and tides.  Once that has taken place erosion takes effect and carries the weathered material away and deposits it somewhere else.
518888
You may be talking about the Banded Iron Formations (in Minnesota) that formed about 2 billion years ago. This was prior to large amounts of oxygen in the atmosphere, thus the iron was in a reducing environment. That is all I can remember about them, if it is what you are refering to.
111289
Your question is way to vague.  There are so many variables to consider that there is no way to answer your question.  \n\nWhat kind of deposite is it?  Is it near surface or very deep?   What kind of other minerals are there?  What kind of permiting is required.  Is it an enviromentaly sensitive area, or in existing workings?  What kind of impurities are involved?  \n\nA feasability study is your first step.
509040
The Earth is not Hollow. Below the 60 Km crust is the semi-liquid Mantle. The core at the center is Solid.
36464
Check out this site: http://www.expanding-earth.org/\nSome scientists may dispute the notion that additional solid matter is created from solar energy by photosynthesis in plants and other living organisms, but they should consider coal beds that were formed from trees in the Carboniferous (~360 to ~290 Ma) but are now buried under deep overburden that accreted later. The huge fossilized tree trunks found in the Petrified National Forest near Holbrook in eastern Arizona are additional evidence of mass from solar energy. Also consider the massive deposits of limestone created by marine fauna (fish, coral, bivalves, microfossils, etc.) in earlier epochs and this growth continues today. Today, piles of leaves, wood chips and fallen trees are rapidly converted to soil by nematodes.  The whole question of added mass needs further research to more accurately determine the volume and sources.
58110
It is quite simple really. There is no 'theory' as some of the posts have indicated. The earth is composed of a number of large plates, which move constantly (the Pacific Ocean today is spreading at 4-5 cm per year). As these plates move, they sometimes slide under one another. As this happens, the upper plate is lifted. This moves rock that was deposited in an ocean environment slowly upwards and often to the top of mountains. The process takes millions of years, so it is likely the rocks that contain the shells on the top of the mountain your husband refers to are tens of millions of years old, or older. \n\nA perfect example is Mount Everest, which has carbonate rocks (with shells) at the peak. Other examples are many parts of the Rocky Mountains in North America, and the Alps in Europe. The Sierra's in California also contain carbonate rocks in many places that did in fact originate in what is now the Pacific Ocean. It is not rare and not mysterious or theoretical. \n\nThe names of these processes, in case you want to learn more, are plate tectonics (previously called continental drift), subduction (one plate under another), orogeny (mountain building), and carbonate sedimentology( deposition of carbonate rocks).  I'm including some links with basic explanation of the concepts. \n\nAnimated illustrations of plate tectonics:\nhttp://www.ucmp.berkeley.edu/geology/tectonics.html\n\nIllustration of subduction:\nhttp://www.platetectonics.com/book/page_12.asp\n\nOrogeny:\nhttp://www.uwgb.edu/dutchs/platetec/orogeny.htm\n\nCarbonate sedimentology (great pictures of carbonates in mountains (sea shells):http://epswww.unm.edu/sed/home.htm\nOther carbonate sedimentology links:\nhttp://www.unige.ch/sciences/terre/geologie/w_groups/carbonate_sedimentology/webmain.html\n\nIf you want to see my explanation for how sea shells form in the ocean go to this question:\nhttp://answers.yahoo.com/question/index;_ylt=AiyMjODIRNiCqQ3uGA0_ICPsy6IX?qid=1006011004317
754788
www.geology.com\n\nSeriously...\nGo there.
799885
This is a great way to begin understanding the different forces that shape the land.  It is important to remember how the rocks came to be found, Metamorphic rocks from Michigan that may have been dug up from a deep quarry or found on the surface exposed by glacial action.  In N Carolina they could be sedimentary rocks exposed by water erosion.  In Florida they could very likely be calcium carbonate deposited by ancient coral reefs.  A simple understanding of these and other rock forming processes would make a prize winning 4th grade report.  Good Luck!
635398
This is dependent on how much sediment is deposited on top of the bedrock.\n\nIn some places, the bedrock is exposed. In others, the bedrock is very deep.\n\nIn areas closer to the coast, termed "coastal plains", the bedrock is usually deeper than anywhere else. This is b/c of all the sediments deposited due to rises & falls of sea levels.\n\nAs you move closer to mountainous areas, the bedrock is relatively shallow.\n\nAs for your other question, it would depend on the type of bedrock as to whether it would be stable & sturdy enough to do what you are proposing.\n\nMetamorphic & igneous bedrock are stable. Some places like in Florida have sedimentary limestone bedrock. That would not be a good place for a "bomb shelter".
391814
Plutonic rocks are those which have have solidified from magma while still underground. the significance of finding them at the surface is that their presence implies that the ground has been uplifted sufficiently for all the overlying rock to have been eroded.
893155
anywhere that was undetwater for a significant time in geologic history
530611
The Precambrian is more of an eon than an era.  The Precambrian period refers to everything that occurred before about 600 million years ago.  Since the Earth is about 4.6 billion years ago, that means the Precambrian was 4 billion years long.\n\nIn terms of geological events in the Precambrian, everything from the formation of the planet, the hypothesized impact that tore off the chunk of rock that would become our moon, the cooling of the molten Earth and formation of the continental plates, the condensation of water and formation of the oceans, the abiogenesis of life, the formation of single-celled organisms, the development of photosynthesis, and the subsequent atmospheric pollution that created our oxygen atmosphere, even the first multi-cellular life all occured in the Precambrian Eon.\n\nThe next period, from 600 million years ago on, is known as the Phanerozoic Eon.  It is split up into the Paleozoic, Mesozoic, and Cenozoic.\n\nThe Paleozoic was the longest period, from 600 million years ago to about 240 million years ago.  It was during this time that every living Phylum of multicellular animal evolved.  At first the seas were the only place where life existed, dominated by things like trilobites, crinoids and ammonites.  Fishes evolved in this period, and about mid-way through the very first land plants started to take root on the continents.  Insects soon followed, and then amphibians, which evolved into reptiles by the end of the period.  The Paleozoic ended with the largest mass extinction the Earth has yet seen, at the end of the Permian.  More than 90% of all species on Earth at the time went extinct.\n\nFollowing the Paleozoic was the Mesozoic.  Sometimes called the Age of Reptiles, the Mesozoic is split into three periods, the Triassic, Jurassic, and Cretaceous, and lasted until about 65 million years ago.  It was during this time that dinosaurs evolved, and became the dominant life on the planet.  There were other notable reptile groups as well, such as pterosaurs, plesiosaurs, icthyosaurs and mosasaurs, and groups such as the mammals and birds also evolved during this period.  Flowering plants also made their first appearance near the end of this period.\n\nFollowing another mass extinction at the end of the Cretaceous came the Cenozoic Era, also known as the Age of Mammals.  Adaptive radiation after the dinosaurs went extinct took the mammals from small, scurrying possum and shrew-like things into the wide array of hippos, horses, cats, dogs, bears, indricotheres, elephants, bats, monkeys and brontotheres of this age.  Partway through the Era, in the Oligocene, grasses evolved and changed much of the landscape of the planet as open prairie became a dominant ecozone.  This is the era we still live in today, our modern Holocene period is the latest section of the Cenozoic.
530600
Physical and Chemical weathering of rock \n\nerosion is only related to the transport of rock and sediment
426456
http://www.geology.sdsu.edu/how_volcanoes_work/subducvolc_page.html\n\nstratovolcanoes\n\nbut on land your answer is probably going to be basaltic
664494
Regional metamorphism as the name implies happens over a large area and is related to large scale tectonics such as ocean closure.  Mountain ranges are areas of regional metamorphism for example.\n\nYou would be more likely to find localised thermal metamorphism in volcanically active areas due to the influx of magma.  This would probably erase any signs of regional metamorphism in the immediate area unless the regional was very high grade.\n\nIt all depends on the type of volcano as subduction related vulcanism occurs on a wide area and may have associated regional metamorphism, where as hotspot or spreading ridge vulcanism doesn't have the compression forces.\n\nComplicated but that's Geology for you