Term
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Definition
| Measure of resistance to flow, the greater the viscosity the harder it is to get a material to flow. |
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Term
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Definition
| characterized by short lived explosive outbursts of pasty lava ejected a few tens of hundreds of meters into the air. |
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Definition
| Powerful, continuos gas blast eruption and the ejection of large volumes of pumice. |
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Term
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Definition
| large composite cones that may generate a type of mudflow. These destructive flows occur when volcanic debris becomes saturated with water and rapidly moves down steep volcanic slopes generally following gullies and stream valleys. |
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Term
| Types of pyroclastic flows |
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Definition
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Term
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Definition
| contains mostly vesiculated material |
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Definition
| contains denser material. glowing avalanches, capable of racing down steep volcanic slopes a speeds that can exceed 200 kilometers. |
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Definition
| consists of hot gasses infused with incandescent ash and larger lava fragments |
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Term
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Definition
| volcanic fragments, ash, volcanic glass, pumice, and crystals |
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Term
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Definition
| large depressions wit diameters that exceed one kilometer and have a somewhat circular form. |
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Term
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Definition
| mounds formed when lava is too viscous to flow away from the vent |
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Term
| Composite volcanoes stratovolcanoes |
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Definition
| Contain alternating layers of pyroclastic deposits and lava flows,Explosive eruptions producing ash clouds and pyroclastic flows,Found almost exclusively in volcanic arcs related to subduction zones. DANGEROUS EXPLOSIVE RING OF FIRE |
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Term
| Cinder cones (scoria cones) |
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Definition
| built from ejected lava fragments that take on the appearance of cinders as they begin to harden in flight. |
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Term
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Definition
| low viscosity magma flows up along km long cracks in the crust, often form continental rifts forms flood basalts |
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Term
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Definition
| lava spreads out over large areas |
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Term
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Definition
| produced by the accumulation of fluid basaltic lavas and exhibit the shape of a broad slightly domed structure that resembles a warriors shield. Low viscosity magma, LARGEST |
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Term
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Definition
| discordant bodies that cut across bedding surfaces or other structures in the host rock. diagonal odd looking deals |
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Term
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Definition
| nearly horizontal, concordant bodies that form when magma exploits weakness between sedimentary beds. |
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Term
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Definition
| ignious intrusions that can lift sedimentary strata, a relatively small lens shaped intrusive, flat on the bottom with the top convex upwards |
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Term
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Definition
| a large discordant intrusive, greater than 100 square kilometers (40 sq. mi.) in map area |
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Term
| viscosity is controlled by two things |
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Definition
temperature and composition
Higher T = lower viscosity
Higher silica content = higher viscosity. Felsic magmas don't like to flow |
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Term
| Explain the relationship between viscosity and gas to volcanic explosiveness. |
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Definition
| If you have a less viscous magma flow it will be more violent than a more viscous one, also if you have more Violates in the magma it also makes it more violent and explosive. Without the gas it leaves the magma more viscous and not as violent |
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Term
| Explain the difference between pahoehoe and aa lava |
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Definition
| aa lava flows have surfaces of rough jagged edges and spiny projection, it is slow moving and basaltic. Pahoehoe flows are fluid and ropy, they exhibit smooth surfaces that often resemble the twisted braids of ropes It means on which one can walk. |
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Term
| Explain difference between a dike and a sill. |
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Definition
| a dike is a discordant body that cuts across rock layers, sills are usually horizontal concordant bodies that form when magma exploits weakness between sedimentary beds. |
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Term
| Name the type of igneous rocks (intrusive and extrusive) found at the three types of plate margins |
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Definition
| 1 along convergent plate boundaries where plates move towards each other and one sinks beneath the other 2. along divergent plate boundaries, where plates move away from each other and new seafloor is created, 3 areas within the plates proper that are not associated with any plate boundary. |
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Term
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Definition
| refer to all changes in volume and or shape of a rock body. Most crustal deformation occurs along plate margins. As the plates interact along their boundaries, tectonic forces deform the involved rock units . |
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Term
| Ways that rocks can be deformed |
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Definition
| Elastically, plastically and fracture |
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Term
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Definition
| return to their original shape and size when the stresses are removed |
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Term
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Definition
| don't return to their original size and shape when the stress is removed. in ductile rocks causes folding and flowing. |
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Term
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Definition
| Break in many ways. occurs when the rock is brittle and in this case faults are formed. |
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Term
| Convergent Plate Boundaries |
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Definition
| Characterized by horizontal compression (directed pressure) |
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Term
| Divergent Plate Boundaries |
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Definition
| Characterized by vertical compression (directed pressure)Your book uses the term tension |
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Term
| Transform Plate Boundaries |
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Definition
| Characterized by horizontal shear (directed pressure) |
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Term
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Definition
| Limbs, Fold Axis, Axial Plane |
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Term
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Definition
| are the two sides of the fold |
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Term
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Definition
| is a line drawn along the points of maximum curvature of each layer. he fold axis is usually horizontal (parallel to the surface). However in more complex folding, it is often inclined at an angle known as the plunge. |
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Term
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Definition
| is am imaginary surface that divides a fold as symmetrically as possible. |
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Term
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Definition
| Fold hinge is not horizontal |
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Term
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Definition
| Anticline syncline and overthrust |
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Term
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Definition
| usually arise by upfolding or arching, of sedimentary layers and are sometimes spectacularly displayed along highways that have been cut through deformed strata. |
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Term
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Definition
| almost always found in association with anticlines are downfolds or troughs. |
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Term
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Definition
| when they start to overlap each other |
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Term
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Definition
| when younger layer is above older layer; when hanging wall block moves down relative to the footwall block. |
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Term
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Definition
| when older layer is above younger layer. dip slip faults in which hanging wall block moves up relative to the footwall block |
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Term
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Definition
| Reverse faults having dips less than 45 degrees so the overlying block moves nearly horizontally over the underlying block. |
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Term
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Definition
Footwall blocks form linear ridges; movements along normal faults produces alternating uplifted block faults...
is the development of two reverse faults causing a block of rock to be pushed up |
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Term
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Definition
Hanging-wall blocks form valleys; down dropped blocks
is produced when tensional stresses result in the subsidence of a block of rock. On a large scale these features are known as Rift Valleys |
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Term
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Definition
| fault that cuts through lithosphere and accommodate motion between two large tectonic plates. Strike slip |
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Term
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Definition
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Term
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Definition
| fractures or discontinuities in a rock with no relative sliding or movement on either side, They are resulting from the release confining stresses |
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Term
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Definition
| Form by crustal tectonic stresses as opposed to stresses induced by topography. Normally vertical |
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Term
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Definition
Deepening upward.
Fining upward. |
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Term
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Definition
Shallowing upward.
Coarsening upward |
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Term
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Definition
| the oldest life form known |
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Term
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Definition
| slug-like animals that are covered in spines and have two large shells at either end of their bodies |
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Term
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Definition
| a variety of marine environments. Change in the sea level, newly exposed land in the north was eroded by rivers carrying sediments to the sea in the south, Permian completely exposed. |
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Term
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Definition
| shallow marine deposition |
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Term
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Definition
| shallow marine deposition, sea levels decreasing |
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Term
| Why are meteorites important? |
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Definition
| They are some of the oldest rocks around, |
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Term
| Why the earth must be very old: |
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Definition
| sedimentary strata, the total thickness of strata, and the time needed to accumulate so much takes wayy longer. |
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Term
| Because there is little physical evidence that Earth's physical processes in the past were acting at faster rates, |
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Definition
| we can conclude that the Earth must have been around for a significant amount of time |
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Term
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Definition
Deepening upward.
Fining upward. |
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Term
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Definition
Shallowing upward.
Coarsening upward |
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Term
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Definition
| the oldest life form known |
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Term
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Definition
| slug-like animals that are covered in spines and have two large shells at either end of their bodies |
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Term
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Definition
| a variety of marine environments. Change in the sea level, newly exposed land in the north was eroded by rivers carrying sediments to the sea in the south, Permian completely exposed. |
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Term
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Definition
| shallow marine deposition |
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Term
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Definition
| shallow marine deposition, sea levels decreasing |
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Term
| Why are meteorites important? |
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Definition
| They are some of the oldest rocks around, |
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Term
| Why the earth must be very old: |
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Definition
| sedimentary strata, the total thickness of strata, and the time needed to accumulate so much takes wayy longer. |
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Term
| Because there is little physical evidence that Earth's physical processes in the past were acting at faster rates, |
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Definition
| we can conclude that the Earth must have been around for a significant amount of time |
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Term
| Uniformitarianism definition: |
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Definition
The present is the key to the past, Geological processes have remained uniform over time and slight changes over long periods can have large scale consequences
the physical chemical and biological laws that operate today have also operated in the geologic past. |
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Term
| Uniformitarianism does NOT mean: |
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Definition
Catastrophes never occur,
Physical conditions on earth never change
Physical processes always occur at the same rate or intensity |
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Term
| Uniformitarianism DOES mean |
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Definition
we can test whether catastrophes have occurred
we can test if physical conditions on earth have changed and if so how? |
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Term
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Definition
| means placing rocks in their proper sequence of formation, first second third etc |
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Term
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Definition
| basic principals for deciphering the spatial and temporal relationships of rock layers |
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Term
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Definition
| layers of sediment are generally deposited in a horizontal position |
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Term
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Definition
| the oldest layer occurs at the base and is overlain by progressively younger rock layers |
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Term
| Law of Cross Cutting Relations |
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Definition
| if a body or discontinuity cuts across a stratum it must have formed after that stratum |
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Term
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Definition
| if a rock body (rock B) contained fragments of another rock body (Rock A) it must be younger than the fragments that it contained. The intruding rock (rock A) must have been there first to provide the fragments. |
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Term
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Definition
| correlating rocks demonstrates equivalency between rock units. Based on rock type, sequence of lithostratagraphic units. |
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Term
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Definition
| formations are basic units, and each are subdivided into members, lump formations together to get group Lump groups together to get super groups |
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Term
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Definition
| relative ages of rocks can be correlated using too fossils |
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Term
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Definition
fossils succeed each other in a recognizable order throughout time
In any sequence of sedimentary layers with fossils, the fossils will change from layer to layer.
The pattern of change is consistent for any particular area.
Once the pattern is recognized can be identified in other areas. Just as the rocks become progressively younger upwards, so do the fossils in these rocks |
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Term
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Definition
abundant
easily identifiable fossil
a wide geographic distribution
a short geologic range |
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Term
| Principal of Unconformities |
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Definition
| represents a buried surface of erosion, which means a break in disposition |
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Term
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Definition
| older underlaying layers are tipped and the erosional surface is irregular. |
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Term
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Definition
| rocks above and below the surface of erosion are sedimentary and parallel each other |
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Term
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Definition
| rocks underlying the surface of erosion are crystalline igneous or metamorphic. |
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Term
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Definition
Protons and neutrons have roughly the same mass, and each is about 2000 times as massive as the electron
The number of protons is the same as the number of electrons which orbit the nucleus |
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Term
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Definition
| Nuclei of a given element which have different numbers of neutrons |
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Term
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Definition
| All about probability, the time required for one half of the nuclei in a sample to decay |
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Term
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Definition
| (carbon 14) the radioactive isotope of carbon which is produced continuously in the atmosphere and is used in dating events from the very recent geologic past (the last few tens of thousands of years) |
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