how are geologic time frame different from the time frame used by other sciences?
458581
Geologic time goes back millions, if not billions of years. For example, dinosaurs first appeared on earth between 200 and 240 million years ago, in a time period known as the Triassic. They lived through the Jurrassic until the Cretaceous (65 million years ago) periods. \nIn short geologic time is a time scale that has been put together based on fossil and other evidence to depict the earths past from formation (4.5 billion years ago) to present time.
308686
Geologic time is divided up into 4 categories\n     - Eon (being the longest)\n     - Era\n     - Period\n     - Epoch (being the shortest)\n\nThe Eon that marks a significant bloom of life on Earth is the Phanerozoic. It spans from 543 million years ago to the present day. Within this Eon, there are three eras; the Paleozoic, Mesozoic, and Cenozoic.  the Paleozoic, or ancient Era, contains 6 Periods, the Cambrian, Ordovician, Silurian, Devonian, Carboniferous (which can be broken into the Mississippian and Pennsylvanian Epochs), and Permian Periods.  The Mesozoic Era, the age of the Dinosaurs, can be broken into three Periods; the Triassic, Jurassic, and Cretaceous (which can be broken into the Lower and Upper Epochs) Periods. The Cenozoic Era, the Age of Mammals, is a weird one. It is split into 4 Periods that overlap, the Paleogene, Tertiary, Neogene, and Quaternary Periods.  These are split evenly into 7 Epochs, the Paleocene, Eocene, Oligocene,Miocene, Pliocene, Pleistocene, and Holocene, the Epoch we are in right now.  Now that I'm through with the confusing part, I can show you what it looks like in a Diagram :)\n\nPhanerozoic Eon\n   -- Paleozoic Era\n        ---Cambrian Period\n        ---Ordovician Period\n        ---Silurian Period\n        ---Devonian Period\n        ---Carboniferous Period\n             ----- Mississippian Epoch\n              ----- Pennsylvanian Epoch\n        --- Permian Period\n   -- Mesozoic Era\n        ---Triassic Period\n        ---Jurassic Period\n        ---Cretaceous Period\n            -----Lower Epoch\n            -----Upper Epoch\n   -- Cenozoic Era\n        ---Paleogene Period\n            ------ Paleocene Epoch\n            ------ Eocene Epoch\n        --- Tertiary Period\n            ----- Oligocene Epoch\n            ----- Miocene Epoch\n        --- Neogene Period\n            ----- Pliocene Epoch\n            ----- Pleistocene Epoch\n        --- Quaternary Period\n             -----Holocene Epoch\n\nWe are currently in the Holocene Epoch of the Quaternary Period of the Cenozoic Era of the Phanerozoic Eon.\n\nTo answer your question, Eon is the longest division of geologic time :)
334211
Igneous, they tell us a lot about what the age of the Earth and location of the poles.\n\nSedimentary, tell us the climate of an area and preserve fossils.\n\nMetamorphic, they look cool but are hard to tell anything from.  Their general location tells us of orogenies and faults.\n\nAll rocks are important and different geologists study different things.  Oil bearing shale is important to some geologist since if we can figure out an economical method of extraction we wouldn't be dependent on other countries for oil.\n\nGeology is like a big puzzle, and it's interesting seeing how the pieces fit together.
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.
1011349
You know, it might be kinda fun asking questions through this format, but you will learn it better by actually doing the studying yourself. \n\nRemember that "conservation of matter" has to do with keeping stuff the same. The rock cycle is very broad and covers all the rock processes, both contact and regional metamorphism have changes in crystal types occurring, so sedimentation has to be the best illustration of conservation of matter. \n\nBut go back to your notes and your text and then rewrite the information in your own words to make it stick in your head.
570720
The age of a fossil may be specified in both relative terms (how old it is in relation to other fossils or rock units) and in absolute terms (approximately how many years old it is). One principle of relative dating is called superposition, which holds that in any one place, the lower rock layers (and fossils in them) are older than higher ones, unless there is evidence that the layers have been overturned. This is logical, since the lower sediments would have been deposited first. A related concept is correlation, whereby rock layers (strata) are compared with others in another location on the basis of their mineral composition, fossil content, and other features. When a rock unit or series closely matches those of another area, they are said to be correlated and considered to be of similar age. Correlations are especially reliable when they include index fossils, which are fossils with a limited age range. Good index fossils are easily recognized and widely distributed around the world, so that they aid both local and international correlations.\n\nAbsolute dating complements relative dating by providing a specific (not necessarily precise) chronological age for a given specimen, such as "50 million years before present." In recent years reliable forms of absolute dating became available through the development of radiometric dating methods. These methods are based on the known, regular decay of certain radioactive elements (isotopes) into other isotopes or "daughter products." By measuring the amount of "parent" and "daughter" products in a rock sample, its approximate age may be calculated.\n\nMany people have heard of the Carbon 14 method and assume that fossils are dated by it. Actually, in most cases the C-14 method is useful only on organic material less than about 50,000 years old, which includes many human remains and artifacts, but excludes most fossils. Absolute dating of fossils requires other dating methods such as the potassium-argon or rubidium-strontium methods, which involve isotopes with slower decay rates (longer "half-lives"). Such isotopes are rare in fossils themselves, but may occur in surrounding or adjoining rock layers, yielding an approximate age for the fossil-bearing unit. Using the principles discussed above, scientists also can deduce the approximate age of other layers correlated with the same formation, as well as an approximate age for layers above and below the formation (which would be somewhat younger and older respectively).\n\nThe terms "above" and "below" in this context are used in a relative or stratigraphic sense; that is, they are based on the positions of the units relative to each other (or correlated units), rather than their height above sea level. The branch of geology that deals with the correlation of rock layers is known as stratigraphy (or biostratigraphy when focusing on the fossils within the layers), and is an important tool of paleontologists.
1113546
Time is really comprehended in terms of the individual. Since we all interpret time in about the same way, based on 24 hour earth rotations and 75 year life spans, then we all share the same concept of time. If days lasted 400 hours and people lived 1000 years, then we would all have the same perception of time only it would be different from the way we perceive it now. Time is perfectly comprehend-able and that's why we have terms like the ones you mentioned... it's just relative.
1123972
The length of the year was about the same. The day has gotten a bit longer, so there were around 400 days in a year around 200 million years ago. For fossils only 6.5 million years old, there wouldn't be much difference (perhaps a day or two per year).
26447
Just because petrification can take place in less than one-hundred years (sources?), doesn't mean that all petrification has. \n\nPotassium/Argon dating provides an accurate way to date objects older than 100,000 years. \n\nWe don't assume that dinosaur bones are so old, we know they are.
969401
Time is a thing invented by man.  Planets and such like don't care about time, they just keep on going forever which is a really long time.
457200
Chronicling the duration of geologic eras via the strata of earth formations.
153621
No, based on the fossil record there is as yet no evidence of this. \n\nThere have been hundreds of these reversals in the history of the planet, not just a few.  In addition to that there are even more frequent major 'excursions' where the field changes strength. These take place as frequently as 50,000 year intervals. These excursions are quite useful in dating geologic events as they are preserved in the rock record. By combining high resolution (frequent) excursion measurements with isotopic dating of volcanic ash deposits that are less frequent many events can be dated with some precision. \n\nIt appears that most animals and birds which use magnetic fields to navigate during migration are able to adapt over the thousands of years it takes for the reversals to take place. Since the change in the magnetic field is so small for each generation of a species it appears there is no significant impact.  \n\nI've done paleomagnetic dating in areas like the Great Rift Basin of Africa.
671187
The generally accepted age for the Earth and the rest of the solar system is about 4.55 billion years (plus or minus about 1%). This value is derived from several different lines of evidence.\n\nUnfortunately, the age cannot be computed directly from material that is solely from the Earth. There is evidence that energy from the Earth's accumulation caused the surface to be molten. Further, the processes of erosion and crustal recycling have apparently destroyed all of the earliest surface.\n\nThe oldest rocks which have been found so far (on the Earth) date to about 3.8 to 3.9 billion years ago (by several radiometric dating methods). Some of these rocks are sedimentary, and include minerals which are themselves as old as 4.1 to 4.2 billion years. Rocks of this age are relatively rare, however rocks that are at least 3.5 billion years in age have been found on North America, Greenland, Australia, Africa, and Asia.\n\nWhile these values do not compute an age for the Earth, they do establish a lower limit (the Earth must be at least as old as any formation on it). This lower limit is at least concordant with the independently derived figure of 4.55 billion years for the Earth's actual age.
149545
There are a number of connections between evolution and geology:\n\n1. dating of organisms using geological stratigraphy\n2. fossil records are associated with both\n3. radiocarbon dating can be used in both\n4. geological changes creating new environments for organisms to adapt to\n5. plate tectonics creating new land formations and new climates for migration and adaptation\n6. evolution is used to interpret geological data\n7. geology is used to add details to evolutionary theory\n8. geological information about the earth can describe some of the conditions that organisms had to cope with (ice ages, interglacials, oceanic environments, volcanism, early atmospheres, etc).\n\n\nand I would imagine a lot more as well, but I am not a geologist or an evolutionary biologist!
784524
In general usage, an eon (sometimes spelled aeon) is a period of time arbitrarily designated by humans. Geologists refer to an eon as the largest subdivision of time on the geologic time scale. For example, the Phanerozoic Eon, which is about 550 million years long, covers the period of time during which animals with hard shells that fossilize would have been abundant.\n\nAn eon is composed of several geologic eras, which in turn are composed of geologic periods, which are composed of geologic epochs. We are currently in the Phanerozoic Eon, the Cenozoic Era, the Neogene Period, and the Holocene epoch. Formerly, only one eon existed besides the Phanerozoic: the Precambrian. More recently, the Hadean, Archean, and Proterozoic "eras" of Precambrian time have been considered eons. \n\nThe English word eon is derived from the koine Greek word aion.\n\nAlthough a proposal was made in 1957 to define an aeon to be a unit of time equal to one billion years (1 Ga), the idea was not approved as a unit of scientific measure and is seldom used for a specific period of time. Its more common usage is for any long, indefinite, period of time. The origin is from the Greek root "aion" for "age" or "life force." A similar Latin word "aevum" for age is still present in words such as Longevity and medieval. [1]
637398
1.) the species existed for a short span of geologic time - this is important because it makes it easier to identify certain strata. If they existed for longer periods of time then it would be harder to correlate rocks found in different places. It's like when you find it you say I KNOW this is definitely from ___ period.\n\n2.) they existed worldwide or over a very large area - in order to correlate the geologic age of rocks from continent to continent or across continents it is important that these specie exist all over the world.
737506
Hi. The first three are physical, the fourth is temporal, the rest are mathematical. We think of the fourth as time, but it really is not. Time, when you get down to it, is an infinite series of 'moments', not to be confused with seconds, years, picoseconds, etc. Humans tend to measure the passing of time in rather coarse terms. If you could see time then objects would be stretched out. A human, for instance, would look like a very long worm tapering from very small (an egg) to adult size to bones, which would last the longest.