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112 Cards in this Set
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Stratigraphy |
the study of rock layers and layering. it deals with the classification, correlations and interpretations of stratified ricks which can be sedimentary, igneous, or metamorphic |
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Nicolaus Steno |
first steps toward understanding the strata architecture in earth's subsurface. Studied the rocks in Tuscany in the decade after the establishment of the royal society of london. Established the theoretical basis of Stratigraphy |
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Subdivisions of Stratigraphy |
1. lithostratigraphy: rock physical characteristics to study rock strata 2. biostratigraphy: Fossil Evidence to correlate and interpret rock strata |
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James Hutton |
introduced the principle of actuals - present is key to the past |
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William Smith |
produced first geological map of england, wales and southern scotland |
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George Cuvier |
proposed principle of catastrophism |
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importance of stratigraphy |
1. mineral exploration 2. Hydro carbon exploration 3. coal mining 4. engineering Geology a) road contruction b) tunneling c) bridges |
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Principles of stratigraphy based on Nicolaus Steno's conclusions |
1. principle of layer superposition 2. principle of successive layer formation 3.prinicpal of original layer horizontality 4. principal of original layer continuity 5. principal of inclusion 6. principal of cross cutting relationships 7. principal of rock cooking |
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principal of layer superposition |
in an undisturbed sequence older layers at the bottom and younger layers at the top |
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principle of successive layer formation |
when a layer is forming no layer exists above it other than fluid which layer material were precipitated
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principal of original layer horizontality |
layers of sedimentary rocks were originally deposited horizontally or near horizontal to earths surface, and deposition on steep slope will be washed away before lithification. inclined layers and folded layers are results of disturbance since original deposition |
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Principal of original layer Discontinuity |
assumes that layers were deposited over entire basin (over extensive area) demonstrating lateral continuity and the layers terminate by thinning at basin margins or grading into another type of sediment |
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principal of inclusion |
states that inclusions within igneous rocks are older than rocks that include them. Inclusions are termed Xenolith |
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Xenolith |
rock fragments that are identifiably different from the rock in which they are enveloped |
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Principal of cross cutting relationship |
states that younger features or rock cut across older feature or rocks prominently used in characterizing viens, dykes in igneous rocks |
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Principal of Rock cooking |
an igneous body that thermally alters a body of rock is younger than the altered rock |
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way up structures |
structures die to sedimentary processes with consistent upward or downward orientation |
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significance of way up structures |
1. enable reconstruction of stratigraphical succession 2. indicate top and bottom of sedimentary layers 3. indication of disturbance in sedimentary layers |
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mud cracks |
sedimentary structures in fine sediment that opens upwards (layer top) and narrows downward (layer bottom) to indicate the top and bottom direction in a layer |
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Burrowing |
structures produced by organisms in sediments in the course of their life activities. The burrows as a rule opens toward the top of a layer and closes towards the bottom of a layer |
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Ripple Marks |
sedimentary structures formed as a result of current action on unconsolidated particles at the top of a layer. they exhibit a structure that narrows toward the top of the layer and widens towards the bottom of a layer |
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unconformities |
they are buried erosional or non depositional surfaces between two rock layers. represent break in sedimentation or deposition within rock successions |
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Field indications of unconformities |
1. erosional surfaces showing relief 2. hard grounds 3. discordant dip angles 4. fossil record 5. turncation of bedding planes, dykes and faults 6. Ferrugination structures |
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Hiatus |
the missing time in stratigraphic succession representing the time in which there was a break in deposition
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Haitus' other name |
Lacuna |
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Factors of Unconformities |
1. crustal movements 2. erosion 3. igneous intrusions |
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Disconformity |
unconformity between parallel sedimentary layers. Break in deposition followed by uplift, erosion, and the deposition of the top layer |
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Non-Conformity |
results from the overlaying of eroded igneous or metamorphic rock surfaces formed deep beneath the earth surface by sedimentary layers |
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Angular unconformity |
formed between tilted and un-deformed sedimentary layers involves the deposition of layers horizontally or near horizontal, uplift and tilted followed by erosion and the deposition of a new horizontal bed |
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Geological Time Scale |
system of chronological measurement that relates stratigraphy to time. Used for describing the timing and relationship between events in earths history |
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History of GTS |
1. biblical age - bishop Ussher - 4004 BC 2. relative age 3. radiometric dating i) marie and pierre currie ii) absolute age iii) isotopes a) half life b) parent and daughter atoms |
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Geologic time scale units |
1. eons 2. eras 3. period 4. age |
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Eon |
1. largest unit 2. 4 eons 3. subdivided into eras |
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4 eons |
1. hadeon 2. archean 3. proterozoic 4. phanerozoic |
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Hadean Eon |
1. oldest eon in earth history 2. 4.5 -4 BYA 3. no rock recorf 4. began with our planet formation 5. only molten matter present |
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Archean Eon |
1. oldest record on earth 2. 4-2.5 BYA 3. fossil record established |
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Proterozoic Eon |
1. AKA Precambrian 2. oldest macro fossil record recorded 3. 2.5 - 0.5 BYA |
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Phanerozoic |
1. youngest eon in earths history 2. .5 - 0 billion years old 3. beginning of visible large fossils 4. eras i. paleozoic ii. mesozoic iii. cenozoic |
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what are the eras of the Phanerozoic Eon |
1. Paleozoic 2. mesozoic 3. cenozoic |
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Paleozoic |
1. small resemblance in fossils and modern fauna and floras 2. 500-250 MYA 3. 7 periods 1. cambrian 2. ordovician 3. silurian 4. denonian 5. mississippian 6. pensylveanian 7. permian |
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Mesozoic |
1. some resemblance in fossils to modern fauna and floras 2. 250-65 MYA 3. 3 periods 1. Triassic 2. Jurassic 3. Cretaceous |
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Permian/Triassic border |
90% of species in seas and oceans became extinct |
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Cretaceous/Triassic border |
extinction of major fossil groups ex. Dinosaur |
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Cenozoic |
1.clear resemblance in fossils and modern fauna and floras 2. 65-0 MYA 3. 3 period 1. paleogene 2. Neogene 3. Quarternary |
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stratigraphic correlation |
the study of establishing geochronological relationship between different regions based on geological investigations of rock successions |
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Lithocorrelation |
lithological characteristics |
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bio correlation |
use of fossil record |
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event correlation |
1. physical naturally occurring and induced properties of rock 2. well logging, geophysical investigations
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time correlation |
absolute dating |
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Evolution |
the change in the inherited characteristics of organisms or biological groups over succession of generations leading to diversity in species, morphologies and genetics |
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Fossil Record |
Documentation of life history by fossils |
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Taxonomy |
The study of the principles used in species classification at any hierarchal level |
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Carl Linnaeus |
1. classification based on morphological resemblance 2. systema Naturae - 1758 publication i. hierarchial classifications ii. higher rank groups more inclusive or diversified iii. lower rank groups less inclusive less diversified 3. species as fundamental |
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original Linnaean Hierarchy |
1. kingdom 2. class 3. order 4. Genus 5. Species |
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Improved Linnean Hierarchy |
1. kingdom 2. phylum 3. class 4. order 5. family 6. genus 7. species |
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Jean Baptiste Lamarck (1744-1829) theory of evolution |
1. significant variation in population of same specie 2. environment and morphological changes 3. inheritance of useful organ 4. adaptation |
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Charles Darwin (1809-1882) Theory of evolution |
1. first coherent theory of evolution 2. observation i. significant morphological variability in species ii. inheritance of some morphological variation iii. more individuals born than can survive 3. Species means by natural selection |
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Earth Record |
1. oldest layers usually devoid of fossils 2. microscopic fossils 3. older fossils simple and primitive 4. younger fossils i. complex ii.multicellular iii. exoskeletons |
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Pattern observed in the emergence of life |
earliest life are single celled evolved from inorganic substances through evolution |
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problems occurred with emergence of life |
1. patchy fossil record 2. small fragments of fossils 3. metamorphic processes affected rocks destroy fossils 4. molecules are not fossilized |
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Evidence for Evolution |
1. gradual increasing morphology related to geological events 2. rock formation related to changes in atmospheric composition |
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Dominant elemental composition of early life forms |
CHON 1. carbon C 2. Hydrogen H 3. Oxygen O 4. Nitrogen N |
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minor elemental compositon in early lifeforms |
1. sulphur S 2. Phosphorus P |
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the number of compounds of CHON(SP) that form most of living molecules |
30 |
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combinations of CHON(SP) |
1. CH4 2. NH3 3. CO2 4. H2O
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further combinations of monomers form what |
organic molecules |
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Alekxandr Oparin Model |
1. CHON formed before life forms 2. reducing atmosphere - accumulation of organic molecules 3. organic molecules dissolves into water to form primordial Soup |
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Stanley Miller and Harold Urey 1953 experiment |
1. hydrogenated gases dominant in primordial atmosphere i. CH4, NH3, CO2, H2O 2. formation of amino acids in the lab 3. polymerization |
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Plate tectonics |
the theory that explains the features and large scale motion of the earth's lithospheric place in the present and the past. it combines the concepts of continental drift and sea floor spreading |
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Continental Drift |
the movement of the earth's continents relative to each other |
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Sea floor Spreading |
the process by which new oceanic crusts are formed by volcanic activities at the mid ocean ridge |
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Natural remanent Magnetism |
the permanent magnetism of rock or sediment during formation preserving the record of the earths magnetic field |
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Pangea |
1. super continent during late Paleozoic 2. surrounded by super ocean Panthalassa 3. broke up by rifting i. laurasia ii. Gondwana |
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super ocean |
Panthalassa |
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Fossil Record Evidence of Pangea |
1. therasid Lystosarus found in A africa, india and australia 2. glossopteris Flora - equator to polar circle |
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Paleomagnetic evidence for Pangea |
reconstructed polar wandering path |
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mountain chain evidence for Pangea |
continuity ion mountian ranges appalachian to caledonians of ireland, britain, and scandanavia |
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Deep sea drilling Project |
started in 1968 glomar challenger - atlantic - pacific - indian - jean baptiste lamarck 1744-1829
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joides resolution |
started in 1985
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Chikyu |
started in 2001 significant variation in population of same specie |
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Contributions of Deep Sea drilling project |
1. validation of sea floor spreading 2. validation for continental drift 3. scientific understanding a. earth history b. climate change c. geohazard |
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investigation methods for ocean floor |
1. sonar sounding 2. coring
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ocean floor features |
1. abyssal plains 2. mid oceanic ridge 3. oceanic trenches 4. seamount 5. island arc |
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Abyssal PLain |
4-4.5 km in depth, planar with very low slope |
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Mid Oceanic Ridge |
1. mountain chain towards the centre of the ocean 2. several km in length and ~ 2 km in height 3. associated with volcanic eruption and earth quakes |
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Oceanic trenches |
1.deepest part of oceans 2. can be 11.5 km in depth 3. elongate structures covering small area 4. associated with earthquakes |
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Seamounts |
1. small sized structures 2. several thousand meters in Altitude 3. can rise above level to form island 4. tops can be eroded to form flat topped mountains 5. associated with volcanic activities |
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Island Arcs |
1. elongate chains of small sized islands 2. usually parallel to oceanic trench 3. situated away from continents 4. proximal areas associated with volcanic and earth quake activities |
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Sediment/oceanic crust age distribution |
1. distinct pattern in sediment age distribution 2. age increase as distance from the mid oceanic ridge increases 3. youngest sediment closest to the mid oceanic ridge 4. oldest sediment closest to the continent 5. symmetrical age distribution relative to the mid ocean ridge |
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magnetic zone distribution |
minerals align to magnetic fields during crystallization or deposition 1. normal polarity 2. reverse polarity |
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normal polarity |
magnetic north/south pole and the geographic north/south pole in the same hemisphere |
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reverse polarity |
magnetic north/south pole and geographic north/south pole in different hemisphere |
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alternations magnetic reversals |
polarity zones parallel to mid ocean ridge |
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Volcanoes |
1. common at plate boundaries 2. associated with seamounts 3. associated with island arcs - indonesia 4. can occur in clusters - iceland |
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earthquakes |
concentrated along plate boundaries |
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tectonics |
the study of the process which control the structure of the earth's crust and its evolution focuses on the movement of the crust and the forces initiating motion |
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types of tectonic plate movment |
1. divergent 2. convergent motion 3. transform motion |
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divergent motion |
1. lithospheric plates move AWAY from eachother 2. leads to BREAK of continent 3. mid atlantic ridge 4. ascending current from the asthenosphere initiates movement 5. molten matter from the earth's interior brought to the surface 6. formation of ocean basin |
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mid atlantic ridge |
1. ocean crust is formed 2. seafloor spreading 3. 1-5 cm per year ocean crust formed |
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formation of ocean basin |
1. continental uplift 2. continental rift formation 3. ocean basin initiation 4. mature ocean formation |
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continental uplift |
1. ascending current from asthenosphere 2. elevated altitude |
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continental rift |
1. continents stretching and thinning 2. formation of elongate depression zones 3. faulting 4. volcanism |
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early ocean basin formation |
1. continental crust split into two 2. sea floor spreading generated by molten influx |
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mature ocean basin formation |
1. continued sea floor spreading 2. more new crust formed -abyssal plain expansion |
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convergent motion |
movement of plates against each other |
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oceanic and oceanic crust convergent motion |
1. collision of two oceanic crust - one sunken and the other along an inclined plane 2. inclined plane called benioff or subduction plane 3. collision zone marked as ocean trench on seas floor 4. accretionary prism formed 5. earth's interior heat and friction lead to melting of subduction crust to produce magma 6. volcanic activity as result and lead to island arcs formation |
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ocean and continent crust convergent motion |
1. collision between continental and oceanic crust 2. oceanic crust subducted beneath the continental crust 3. marked by ocean trench parallel to shore line 4. accretionary prism formed 5. associated with earthquakes and magma generation 6. deepest part of oceans 7. can be 11.5 km deep 8. elongate structures covering small area 9. associated with earth quakes
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continent and continent convergent motion |
1. collision between two continental crusts 2. associated oceanic crust subjected 3. narrows and closes ocean 4. mountain chains formed parallel to collision zones 5. earth quakes and volcanism associated with zone 6. himalayas mountains - eurasia and india collision |
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wilson cycle |
the cycle of ocean initiation, expansion and closure John Tuzo Wilson |
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ocean initiation |
divergent motion |
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oceanic crust consumption |
subduction |
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ocean closure |
convergent |