how is evolution of karst submarine springs?
80459
Karst springs are commonly formed by the collapse of the roof of water filled cave passages. In other places the caves open into areas where some other form of erosion like stream and river channels have cut down through the cave and captured the water flow. Many rivers have karst springs in them that supply a great deal of the water to the river. Mammoth Cave in Kentucky, the world's longest cave at 367 miles, drains into the Green River through a spring. \n\nThe caves are initially formed by dissolution of limestone or other soluble rock (there are caves in gypsum and even quartzite) either by rainwater that carries dissolved carbon dioxide (carbonic acid) or by other types of acids that may be in the water. The dissolution of small cracks in the limestone eventually grows into large cave passages, and at some point often emerges from the earth surface at a spring. \n\nHere is an illustration that shows a "resurgent stream" or karst spring:\nhttp://www.cancaver.ca/docs/karst.htm
520870
fifth epoch of the Cenozoic era of geologic time
406328
Okay listen carefully,\n\nOil is not found in caves for Heaven's sake! Oil is found inside porous permeable rocks. That means that tiny holes are interconnected together like a network of capillaries. When you pump out the oil there is no real big void left to cave in. Besides water is sometimes found w/ the oil. Since oil is less dense it rides over the top of the water. So if anything fills the spaces left behind it will be water!\n\nNow the ground will cave in where they pump massive amounts of groundwater out of aquifers found in limestone bedrock.\n\nLimestone dissolves due to natural acids such as carbonic acid. Voids or caverns or caves, whichever you prefer to call them are created & fill w/ water. When the water is pumped out, there is nothing left to support the structures above. The ground caves in & poof you have a sinkhole.\n\nSinkholes have been known to swallow whole blocks in cities. Florida is entirely underlain w/ limestone bedrock. The whole state has sinkholes everywhere.\n\nSo don't be concerned about pumping oil out & leaving gaping holes behind. Those you don't have to worry about. You do have to worry about pumping too much groundwater.\n\nTurn off the water while you are brushing your teeth next time.
431352
Snakes lost their legs on land, not in the sea as previous scientists thought, according to new research by professor of biology S. Blair Hedges and postdoctoral fellow Nicolas Vidal.\n\n"Everyone agrees that snakes evolved from lizards and are close relatives to lizards," Hedges said. "What is controversial is the specific group, whether on the land or in the sea."\n\nScientists estimate that snakes evolved 150 million years ago, Vidal said. For many years, they believed in the terrestrial or land theory, which says that snakes evolved from lizards that burrowed underground.\n\nThen, seven years ago, the discovery of a fossilized marine snake with tiny hind legs fueled the marine hypothesis that snakes lost their legs in the sea. The marine snakes called mosasaurs are now extinct, but their closest cousins, the monitor lizards such as the Komodo Dragon, are still alive today.\n\nHedges and Vidal chose two genes and compared them in lizards and snakes to see how closely they are related. From statistical analysis of these gene sequences, they created a family tree.\n\n"These two genes have accumulated different mutations in the different species," Vidal said. "These differences between the species are used to build the evolutionary trees. Snakes are not closely related to the monitor lizards, which means that they cannot have marine origins."\n\nHedges and Vidal's research is significant because of the comprehensive scope of the snakes and lizards studied. They collected DNA from 64 species representing all 19 families of living lizards and 17 of the 25 families of living snakes, Vidal said.\n\n"We mostly acquired DNA from the soft tissues, blood, shed skin, scales and tips of the tails of the animals," he said. "A very small amount is needed, so we can get the sample without killing the animal."\n\nHedges and Vidal acquired samples from other colleagues, their own collections, fieldwork in South America and pet stores that trade exotic animals, Hedges said.\n\nSome of the samples were difficult to acquire because some snakes and lizards are limited to certain parts of the world, such as remote islands, but it was crucial to their study.\n\n"We felt it was important to analyze genes from all the lizard groups, because almost every lizard family has been suggested as being the one most closely related to snakes," Hedges said. "If we had failed to include genes from even one of the lizard families, we could have missed getting the right answer."\n\nA possible theory to explain why snakes dropped their legs on land is that limbs are not conducive to their burrowing habits, Vidal said.\n\n"The idea is that if you have limbs sticking out, it's difficult to get into small openings," Hedges said. "It's more advantageous, because it enables snakes to get more food and offers safety from predators."\n\nHedges and Vidal did not find the closest lizard relative to snakes, but they did succeed in eliminating the monitor and marine lizards as possibilities.\n\n"This study doesn't answer all the questions," Hedges said. "In most fields, questions aren't answered all at once. They're answered in increments, and in this study, we've ruled out the marine theory, but that still leaves a lot of possibilities."\n\nHedges and Vidal said they hope to find the closest relative to snakes in the next year.\n\n"The work by Dr. Hedges and Dr. Vidal is a tremendous contribution to the body of knowledge," said Bryan Fry, deputy director of the Australian Venom Research Unit at the University of Melbourne in Australia. "Their data provides strong evidence for the terrestrial loss of limbs."
145840
Cool. I hope you found some good ammonites. You may have been in the Cretaceous Western Interior Seaway, which once connected what we now call the Gulf of Mexico to what is now the Arctic Ocean. The Pierre Shale is full of clams, ammonites, and baculites. \n\nThe Western Interior Paleontological Society has some good publications:\nhttp://www.wipsppc.com/#\nHere is link to a Pierre Shale field trip of the WIPS in Colorado:\nhttp://www.paleocurrents.com/baculite_mesa/index.html\n\nHere is an awesome website put together by Dr. Ron Blakey at NAU. For your interests, the first place to start would be paleogeography of the Southwestern US, which has paleogeographic maps of each major period (that include southern Colorado):\nhttp://jan.ucc.nau.edu/rcb7/paleogeogwus.html\nThe top page of his site is at:\nhttp://jan.ucc.nau.edu/rcb7/\n\nYou might also want to buy a copy of "Roadside Geology of Colorado". This series of books is written by geologists who are familiar with the state they write about and describe the geologic features that can be found along the major highways. Here's the cite:\nChronic, H. 1980. Roadside geology of Colorado. Mountain Press Publ. Co., Missoula, Montana, 334 p.\n\nThe Colorado Geological Survey sells a map for $7 that is titled "Colorado Geologic Highway Map" that shows lots of geology information, as well as a lot of other high quality geology related publications:\nhttp://dnr.state.co.us/geostore/ProductInfo.aspx?productid=MI-38\n\nHere is the USGS page for Colorado:\nhttp://www.usgs.gov/state/state.asp?State=CO\n\n\nEnjoy.
1026078
Well,  there is a new island forming just south of the big island.  It is about 3000 feet under sea, and is not expected to break the surface of the ocean for another 10,000 years.  I'd say that is pretty fast in geological terms.
426850
Most people would think that experts agree on an explanation for the formation of such a grandiose site as the Grand Canyon. Surprisingly that isn't so. It is an enigma. The latest attempt to figure it out occurred as late as June last year at the Grand Canyon Symposium 2000. The Colorado River is held generally responsible for carving the Canyon. However, even before the Glen Canyon dam stemmed its awesome desert floods, the river seems hopelessly inadequate to have formed such a geological spectacle. The Colorado River flows west from the Rockies and encounters a raised plateau known as the Kaibab Upwarp. Instead of turning away from that barrier it continues through the plateau. How could it do that? The river is much younger than the Kaibab Upwarp so it could not have progressively cut the Canyon even if the land rose very slowly. In any case, most of the material that was removed from the Canyon seems to be missing, according to a report from the symposium, leaving little evidential support for the original theory that a simple progression of water erosion formed the Canyon we see today. Since the 1930's and 1940's, geologists have searched for other explanations -- that the Canyon once drained to the south-east (reversing the route of the present-day Little Colorado, then joining the Rio Grande and into the Gulf of Mexico. When problems arose with that explanation too, it was proposed that it once flowed NE along one of the present-day side tributaries such as Cataract Creek.
170598
Yes there are. This website tells about it ---\n\nhttp://www.ivc.edu/geology/ocgeo.aspx
98019
you can spend years here....zorathustrn granite,mica schists..various volcanics  in  canyons bottem  are  evidence trhat  an old mountain range...some say  as  high as  todays  rockies...[by base measurments]  was  eroded away  by  ice flows.....oceans came  and  left.....on  ariving  plant and  animal life  contribute  fossil remains and  calcite[the  making of limestone]mud stones and shales....the  various  banding  give us  ideas to the duration  andlife  of the times.....basically  the  areas  above the  river  are  sandstones  shales  and  mudstone....but there is  marble and dolomites....explore....thers  gotta  b   pics  on  net  somewhere
811250
hun.. this is a geology question  \n\n\nclimate change... temperature, co2 levels. \nmany dinasoars were to specialized and could not adapt to the new enviroments\nchange in water levels of world... can be due to temperature \nchange in temperature can lead to more extreem weather conditions of floods and draught\nmore precipitation can change salinity changes of oceans \nAsteroid\ndisease\nVolcanic eruptions.. poison gases into atmosphere.. hence the \nCo2 hypothesis\nCo2 (carbon dioxide) is also a greenhouse gas trapping heat
752486
These are all related to the crusts. \n\nA divergent boundary occurs when two Earth tectonic plates move away from each other, causing a depression or a range. \n\nSubduction occurs underwater when seawater tectonic plates converge into continental plates. Since seawater tectonic plates are more dense than continental plates, it 'subduct's and goes under. \n\nThere's more than 3 types of magma, depending on its temperature, density, and composition.\n\nAs you know, the plate tectonics theory says that the Earth's crust is moving constantly. By applying the observations of divergent boundaries through time (ex, Great Rift Valley created over centuries), that will -support- and -clarify- the plate tectonics theory. So, divergent boundaries being observed serves as evidence and support for the theory.\n\nSubduction occurs in sea-floor spreading, which explains why crusts closer to the mid-atlantic ridge are "warmer" and "younger", while the ones further away, and most likely closer to a subduction zone is colder. This shows that the Earth's crust is once again moving, once again indicating that the theory is true. \n\nMagma is formed when divergent boundaries move away from each other, and is replaced by new crusts formed by magma. The cycle of sea-floor spreading undergoing subduction, sinking under the continental crust, melting into magma, then re-forming  at the Mid-Atlantic ridge.
725776
Water under pressure (i.e. deep underground) can dissolve large amounts of CO2 if there is CO2 around then the water will become carbonated.
374572
to brandijo-ALL of it was under water.  That's how limestone, sandstone, and shale form.  Once the layers of rock were there water eroded them on a large scale to form the canyon.  The top layer at grand canyon is called Kaibab limestone and it is about 200 million years old.\n\nAs for strange things about grand canyon...In the canyon use to live a native american tribe called the Anazi(sp?).  They disappeared and no one knows where or why they went.  Their cliff dwellings have been explored and it's like one day they just up and left and didn't bother to pack like they were coming back someday.\n\nAnother strange incident is the story of a newlywed couple that disappeared on their honeymoon.  I can't remember their names or the details, but there is quite a bit about it in the book "Over the Edge: Death in Grand Canyon"  Really great book.
1049180
aquifers, undergound streams, etc. anything under ground
1072409
They fill naturally with water. \n\nOil is generally found in small pores in rock like sandstone or limestone. The pores range in size from hundredths of a millimeter, to a few millimeters in most cases. In some limestone a form of porosity can form that has much larger pores (vuggy porosity), ranging from centimeters to meters in size in the case of cavernous porosity.\n\nBelow the first few hundred feet of the earths surface all of the pores in rock are filled with water, or oil and natural gas. In most oil reservoirs the water that is there naturally is salt water. Most oil and gas reservoirs have a naturally high pressure when first found, and this natural pressure (often several thousand psi) drives the oil and gas upward and out of the well. Water pushes the oil and gas out of the well, replacing the oil and gas in the rock as it leaves the well. If water did not flow into the voids left by oil and gas, it would be impossible to pump oil out of a well. \n\nWhen the natural pressure is depleted the well is either abandoned or nearby wells can be used to inject more water and create artificial pressure to push the oil up out of the well.   \n\nIf you are wondering if the rock subsides or compacts as the oil is removed, in most cases it does not. The grains in the rock are well cemented and support each other regardless of what is in the pores. In the case of poorly cemented sandstones (called unconsolidated) there can indeed be some compaction and the surface can subside. This also happens with some water wells, and in some areas there has been significant subsidence from both water pumping and oil pumping.\n\nYou might be surprised to learn that in most oil wells only about 50% of the oil is ever recovered. Recovery can range from as low as 20-30% of the oil to as high as 60-70% of it when special methods are applied. Someday if we ever find a new technology that can recover more oil we may be able to go back to long-abandoned oil fields and pump more oil. Current methods of what is called secondary or tertiary recovery involve both water injection into special injector wells and carbon dioxide injection. The water or CO2 helps flush (push) more oil out of the underground sponge-like rock we call an oil reservoir.
165682
A complete answer to this question would require a very large book.  You will need better focus for a short answer.\n\nAcids dissolve most minerals and rocks.  Even water dissolves rocks or rock constituents over a long period of time.  There is fabulous erosion in calcium rich rocks creating tunnels and underground chambers...\n\nAcid rain enhances this process greatly.  Virtually all the salts in the oceans came by the erosion of rock salts over aeons of time spent under the never ceasing rainy seasons.\n\nSome conditions are rock forming or metamorphosing, others are rock dissolving.\n\nHeat and cold are also factors in the deterioration of rock, making it more vulnerable to water and acid rain.\n\nThere are many fabulous websites on rocks and minerals and gemstones.  Just Google some of that and you will pull up two or three super-excellent ones.\n\nTry also Googling "rock geological processes."  Keep it in quotes.
521447
This is same question as "a small stone is dropped from sky". here instead of air there is water, but logic is same. Water resistance plays a major role. Before hitting the floor the pebble achieves the terminal velocity, then moves with constant speed towards the ocean floor. Weight of the stone does not play a role, but shape of the stone does for terminal velocity value. A spherical stone is less resistant that any other shape. [I am assuming it rotates randomly while travelling down, so not considering submarine shape:)].\n\nHow long is still an unanswered question, due to missing data.