Index

Page numbers in italics refer to Figures. Page numbers in bold refer to Tables. accretion, final stage of planetary 339–340 results 281 acid etching, Ar release by 83 results discussed 281–282 activation energy 83, 193, 194 origins of 277–278 adularia, Klokken 99 anorthosite, lunar, Ar source comparisons 176 adularia breccia 288, 291 apatite fission track (AFT) thermochronology 227 40Ar/39Ar dating Apollo missions, dating lunar events 176 methods Appalachian Province, source of hornblende laboratory techniques 291 247, 247 sampling 291 Araguainha impact structure 349 results 289, 290, 291–292 argon results discussed 292–293 atmospheric see also K feldspar in comparisons 11 age equations composition 15–16 40Ar/39Ar 11 contamination 14 K/Ar system 10 palaeo-ratios 179–180 age spectrum calculation by 40Ar/39Ar step-heating component release by non-thermal methods 83 applications component release by step-heating 82–83 chondrite meteorites 334 retention age concept 54 Dellen impact structure 351, 356, 358 solubility 138 exhumation studies 230, 231 various isotopes Haifanggoui Formation studies 280, 281 Martian sources 300 muscovite age standard 70 atmospheric and interior components phengite muscovite diffusion study 117, 307–309, 312 118–121 spectrum due to cosmic rays 300 polyhalite studies 215, 216, 217, 218–219 spectrum of sources 299 36 CO2 laser testing 83–84 Ar theory of 82–83, 91–92 ingress 138 age standards, importance of 2–3 problem in chondrites 335 albite spindles as domains 110 production by cosmic rays 175 Allende meteorite 183 production of 13, 34 Alps role of 14 36 Central, Togni Quarry as source for age Aratm 34 standard 69 36Ar/38Ar, trapped in meteorites 302–303 Northern Calcareous Alps 37Ar orogenic history 208 production of 13, 34 palaeotemperature and age analysis recoil 34 history of research 210, 210 effects of 34–35 methods 210–211 experiment to test results methods 35–36 40Ar/39Ar dates 215, 216, 217, 218–219 results 36–40 illite crystallinity 219 results discussed rock descriptions 211–212, 215 age correction 48–49 thin sections 213, 214 comparison with theory 47–48 vitrinite reflectance 219 Fish Canyon plagioclase 40, 43–46 results discussed 220–221 hornblende Hb3gr 47 results fluid inclusion analysis 219–220 summary of implications 49–51 saltmines 208–209 role of 4, 14 setting 208, 209 37Ar/39Ar in recoil gas 54 37 alteration ArCa 34 problems in dating 155 38Ar see also sericitization cosmic ray induction 175–176 Andean Cordillera, Pleistocene andesites ascent rate from 37Cl 178–179 calculations 147 production by cosmic rays 175 andesite, Pleistocene, ascent rate calculations 147 production by neutron absorption 175 angiosperms role of 4 40Ar/39Ar dating of first appearance spike calibration 53 methods, sampling 279–280 terrestrial production 177–178 methods laboratory procedure 280 use as tracer 11 368 INDEX argon (Continued) results 289, 290, 291–292 38Ar/37Ar results discussed 292–293 exposure ages 176–177 tectonic setting 285–286, 287, 288 isochron 178 Brione (Alps), source for age standard 69 39Ar Brunhes-Matuyama Chron boundary age 18, 26, 28 as proxy for K concentration 53 burn patterns, CO2 laser testing 80–81 recoil 33, 299 39 ArK 34 cadmium (Cd) shielding 13–14, 335, 337 39 Arm 34 calcium 40Ar 40Ca neutron activation 176 concentration measurement, isotope dilution 53 Ca/K ratio in plagioclase 168–171 diamond dating 180 correction factor 13, 14 problems of inherited 155 effects in nuclear reactor 13 problems of non-radiogenic 297, 299 interference by neutron fluence 177 40Ar* 11, 34, 82 Caledonian Province, source of hornblende 247, 247 40Ar*-40K, in mineral standards 63 calibration, statistical optimization approach 40Ar/36Ar future 29 atmospheric 13 misrepresentation 25–26 palaeo-atmospheric 179–180 misuse 24–25 40Ar/39Ar dating technique 1, 13 practicalities 21–22 assumptions to be fulfilled 12–13 use 22–23 development of 11 Canada, Heinrich events 245 measurement of isotopic ratios 13 Central Atlantic Magmatic Province (CAMP) 159, 162 overviews age of sericitization 171 methodological developments 2–4 handling sericitization problems 161–162, 163, 164 technique applications 4–5 Central China Orogen 189 secondary standards 53 Central Dabie Complex 191 Arrhenian non-linearity (ANL) plot 109, 110, 111, chassignites 297, 311, 317, 318 113, 114 chemical abrasion-thermal ionization mass spectrometry Arrhenius parameters 83 (CA-TIMS) 22 Arrhenius plot 265 China, Central China Orogen 189 40Ar/39Ar step-heating 91–92, 93–94, 93 chlorine (Cl) point of inflection 193 concentrations and mineralization dating 179 use in phengite muscovite diffusion study correlation with 40Ar in diamonds 180 Arrhenius data 121–123 problems in 40Ar/39Ar meteorite dating 301–302 Arrhenius data inversion 126–130 various isotopes astronomical calibrations 18, 23–24 36Cl astronomical tuning chronologies 21, 23–24, 63 evidence in early solar system 183–184 atomic absorption, for K concentration 53 half life 183 Australia, Pilbara greenstone, muscovite history of 175 thermochronology 100 interference by neutron fluence 177 in sodalite 177–178 Bakersville (North Carolina), oligoclase samples 138 37Cl neutron absorption 175, 178 basalt chondrite meteorites 3He monitoring 176 40Ar/39Ar dating Sa˜o Tome´ sample dating 86, 87 H type 339–341 Tristan da Cunha sample dating 88, 88, 182–183 L type 336–339 basaltic volcanic events, problems of dating 155 LL type 341–343 biotite problems associated 334–336 mineral standard summary of age data 343 recoil testing classification 333 method 55–56 Churchill Province, source of hornblende 247, 247 results 56, 56 clay minerals results discussed 56–61 dating problems 33 recoil-induced loss 34 recoil problems 53–54 Bishop Tuff, age 26, 28–29 special techniques for dating 54 blanks, furnace v. laser 84–86 climate change, relation to Heinrich events 254–257 blocking temperature 91 closure temperature and closure theory 91 Bouillante geothermal system concept of 193 adularia breccia 288, 291 hornblende 245, 247 40Ar/39Ar dating muscovite 123 methods plagioclase 137–138, 139 laboratory techniques 291 relation to staircase age spectrum of sampling 291 K feldspar 193 INDEX 369

CO2 lasers results initial development 79 40Ar/39Ar date 358–359 limitations 79 composition 355 new developments 80 trapped water 357 description 80, 81 results discussed system performance 88–89 inherited argon 360–362 system tests perthitic texture 359–360 blanks 84–86 water history 360 burn patterns 80–81 significance of results 362–363 rastering 86–87 Dellenite 352 step-heating 82–84 Denali Fault see Eastern Alaska Range noble gas extraction 3 depth-profiling, UV laser 137, 138, 266 Colorado, San Juan volcanic field, as source of application to Ar diffusion and solubility measurement mineral standard 63 methods Cone crater 176 samples 138 cooling ages, defined 193 sample treatment 138, 143 Cornubian batholith, mineralization dating 179 modelling 143–144 cosmic rays results 140, 141, 142, 144–146 exposure of meteorites 300 results discussed CRE ages 4, 176–177, 317, 339 diffusion 146–148 see also shergottites solubility 148–152 induction of noble gases in meteorites 175 deuteric coarsening 107 spallation 335 Devonian, atmospheric Ar ratios 179 Crete, astronomically tuned sections 18, 28 Dhofar shergottite (Dho378) 318, 319 crushing and Ar release by 83 diagenetic minerals, special techniques for dating 54 cryptocrystalline rocks, dating problems 33 diamonds crystal defects dating Zaire cubes 180 density effect 54 micro-inclusion composition 175 effect on dating 54 differential extraction and step-heating theory 82–83 crystallization degree in clays, effect on dating 54 diffusion Curtis, Garniss, early work 9 experimental techniques 2 experiments in vacuo 112–114 d0 value 34 geological realities 111–112 Dabie collisional complex 191 measurement of Ar in Itrongay feldspar 266 Dabie Mountains 191 methods of analysis Dabie Orogenic Belt 191 laser ablation 267–268 Dabie-Sulu orogen 189 sample preparation 266–267 Dakhleh impact event 349 results 268–270 decay constants results discussed 270–272 accuracy 3, 15–17 summary of model 272–273 for electron capture and beta decay of 40K22 measurement of Ar in phengite muscovite 117–118 problems of uncertainties 21, 24 Arrhenius data 121–123 Deccan traps, plagioclase dating problems 159, Arrhenius data inversion 126–130 160, 162 modelling mixing 123–126 deep pathway 137 pressure effects 130–133 defects in crystal structure 137 step-heating observations 118–121 density effect 54 summary 133–134 effects on dating 54 measurement of Ar in labradorite and oligoclase role in diffusion 265 methods degassing and diffusion see under diffusion sample preparation 138 degassing curves, use in sericite detection 161–162 techniques 138, 143 Dellen impact crater, glass age study model 143–144 description 352 results 144–146 geological setting 350, 351–352 results discussed 146–148 methods of study mechanisms 137, 266 40Ar/39Ar dating 354, 356 modelling 109 electron microprobe 354 consistency of 109–111 FT-IR spectroscopy 354 see also diffusion domains hydrogen isotope analysis 354 observations on 107–109 optical microscopy 353 rate relation to temperature 265 Raman spectroscopy 354 role of Fick’s Law 109 SEM 352, 354 role of phonons 108 previous age research 351, 352 in solids, mathematical treatment 108 petrography 356–357 use in technique development 2 370 INDEX diffusion domains Fish Canyon plagioclase (FCp) 35 multi-diffusion domain (MDD) experiment to test 37Ar recoil analysis 117 methods 35–36 model 266 results 36, 37, 38,39 model future results discussed 40, 43–46 extra-terrestrial material 102 Fish Canyon sanidine (FCs) K-Ar thermochronology 98–99 age 3, 16, 17–18, 21, 26 K-Ca thermochronology 99–102 correlation to orbital tuning 23 model merits 95–96 as mineral standard 63 model shortcomings 96–98 experiment to test relation to cooling history 190, 193 methods theory 92–95 40Ar/39Ar technique 65–66 multi-path (MP) diffusion model 190, 193, 265 sampling 64 diffusion v. fluid-mediated transport 107 separation 64–65 discrete domain theory 109–110 results 65,66 checking for consistency 109–111 Fish Canyon Tuff, exposure for standard mineral geological realities 111–112 sampling 64, 64 double-vacuum resistance furnace 79 fission track annealing 107 doubly-pumped window 79, 80 flame photometry, for K concentration 53 flood basalts see large igneous provinces (LIP) Eastern Alaska Range fluence monitor early research 226 defined 11 exhumation history Fish Canyon sanidine 17–18 methods of analysis fluid inclusion analysis laboratory techniques 228–230 mineralization dating 180–183 multi-domain diffusion model 230–231, 233 Northern Calcareous Alps, Haselgebirge Formation sampling 227, 228 methods 211 results results 219–220 biotite ages 233–235 Rhynie chert 179 feldspar age constraints 235 fluid-mediated transport v. diffusion 107 feldspar MDD thermal models 232, 235–236 French West Indies, Bouillante geothermal system results discussed 236–239 adularia breccia 288, 291 geological setting 226, 227–228 40Ar/39Ar dating electron microprobe (EMP) analysis, methods muscovite B4M 70, 72–74 laboratory techniques 291 Ethiopian traps, plagioclase dating problems 159, 162 sampling 291 Evernden, Jack, early work 9 results 289, 290, 291–292 exhumation rate 225 results discussed 292–293 Eastern Alaska Range tectonic setting 285–286, 287, 288 early research 226 Fuping Terrane 190 exhumation history methods of analysis Gangdiseˆ feldspar 110–111 laboratory techniques 228–230 geochronometers, controls on 107 multi-domain diffusion model 230–231, 233 geomagnetic polarity timescale 26, 28 sampling 227, 228 geothermal activity timing in Bouillante results adularia breccia 288, 291 biotite ages 233–235 40Ar/39Ar dating feldspar age constraints 235 methods feldspar MDD thermal models 232, laboratory techniques 291 235–236 sampling 291 results discussed 236–239 results 289, 290, 291–292 geological setting 226, 227–228 results discussed 292–293 extraterrestrial materials 4, 102 tectonic setting 285–286, 287, 288 see also meteorites glass-enveloped mass spectrometer 9 gold-bearing mineral veins, fluid inclusion Faneromeni section (Crete) 18, 28 dating 180 fast pathway diffusion 137 grain size fast-path diffusion 266 effect on recoil 33, 53–54 fault gouge, recoil testing 54 effect on standard mineral see muscovite B4M feldspar effect on thermochronology 98 alkali see albite; K feldspar impact on Arrhenius diagrams 109 plagioclase see under plagioclase feldspar Grande De´couverte-Soufrie`re (GDS) volcanic system Fennoscandia see Dellen impact crater adularia breccia 288, 291 Fickian diffusion and Fick’s Law 109, 112 40Ar/39Ar dating INDEX 371

methods mineral standard laboratory techniques 291 recoil testing sampling 291 method 55–56 results 289, 290, 291–292 results 56, 56 results discussed 292–293 results discussed 56–61 tectonic setting 285–286, 287, 288 Huaiyang metamorphic belt 191 greenschist facies, dating 157, 165–166 hydrogen, diffusion in silicon 108–109 Grenville Province, source of hornblende 247, 247 hydrothermal systems Guadeloupe, Bouillante geothermal system Bouillante geothermal system adularia breccia 288, 291 adularia breccia 288, 291 40Ar/39Ar dating 40Ar/39Ar dating methods methods 291 laboratory techniques 291 results 289, 290, 291–292 sampling 291 results discussed 292–293 results 289, 290, 291–292 tectonic setting 285–286, 287, 288 results discussed 292–293 dating 157, 180–183 tectonic setting 285–286, 287, 288 study and the role of 40Ar/39Ar 5

Haifanggou Formation I-Xe dating 178 40Ar/39Ar dating ice-rafted detritus, provenance studies 245 methods ideograms 335 laboratory procedure 280 igneous rocks, dating with K-Ar 10 sampling 279–280 illite crystallinity results 281 Northern Calcareous Alps, Haselgebirge Formation results discussed 281–282 methods 211 fossil content 278 results 219 lithological description 278–279, 279 illite-smectite, special techniques for dating 54 halogen ratios, fluid inclusions 181, 182 impact event studies Haselgebirge Formation 208, 209 Dellen impact crater, glass age study Hawk Mine, Bakersville (North Carolina), description 352 oligoclase samples 138 geological setting 350, 351–352 HED meteorites 341 methods of study Heinrich events 245 40Ar/39Ar dating 354, 356 H3 characteristics 252 electron microprobe 354 40Ar/39Ar hornblende ages 253–254 FT-IR spectroscopy 354 detrital carbonate 252 hydrogen isotope analysis 354 magnetic susceptibility 252 optical microscopy 353 oxygen isotopes 246, 253 Raman spectroscopy 354 radiogenic isotope provinces 252–253 SEM 352, 354 terrigenous biomarkers 253 previous age research 351, 352 230 Thxs 253 petrography 356–357 H3 mechanism 257–260 results relation to climate change 254–257 40Ar/39Ar date 358–359 sedimentary evidence 246 composition 355 helium (He) trapped water 357 induction in iron meteorites 175 results discussed retention 107 inherited argon 360–362 3He perthitic texture 359–360 cosmic ray induction 175–176 water history 360 Hawaiian basalts 176 significance of results 362–363 Hemerden tungsten (Cornwall), dating 178–179 impact crater record 333, 349 Higashi-akaishi peridotite, fluid inclusion role of 40Ar/39Ar 4 studies 181 Inter-Tropical Convergence Zone (ITCZ) 255 Himalaya, Main Central Thrust, muscovite iodine, subducting slab release 181 thermochronology 98 island arc volcanism dating by Bouillante hornblende geothermal system 40Ar/39Ar age and provenance 245, 253–254 adularia breccia 288, 291 sources in ice-rafted detritus 247–248 40Ar/39Ar dating closure temperature 247 methods Lone Grove pluton 35 laboratory techniques 291 experiment to test 37Ar recoil sampling 291 method 36 results 289, 290, 291–292 results 39, 40, 40, 41, 42 results discussed 292–293 results discussed 47 tectonic setting 285–286, 287, 288 372 INDEX isochron plots 80Kr, cosmic ray induction 175–176 inverse 307 81Kr in cosmic ray dating 176 regular 303–307 Itrongay feldspar (low sanidine/orthoclase) La Garita Caldera (Colorado), as standard age 266 mineral source 64 description 266 labradorite diffusion study Ar diffusion and solubility measurement methods of analysis methods laser ablation 267–268 samples 138 sample preparation 266–267 sample treatment 138, 143 results 268–270 modelling 143–144 results discussed 270–272 results 140, 141, 142, 144–146 summary of model 272–273 results discussed history of research 266 diffusion 146–148 solubility 148–152 J parameter 54 Lanqi (Tiaojishan) Formation Japan, Sanbagawa metamorphic belt, fluid inclusion 40Ar/39Ar dating studies 181 methods jet stream 254 laboratory procedure 280 sampling 279–280 K (potassium) results 281 abundance 1 results discussed 281–282 concentration measurement 53 fossil content 278 effect of neutron activation 3 lithological description 279, 279 K–Ar age, B4M muscovite 69 Lappajarvi impact 349 K–Ar decay scheme, constants 16 large igneous provinces (LIP) K–Ar thermochronology 98–99 problems of dating 155 K–Ca thermochronology 99–102 handling age reduction 159–160 various isotopes importance of filtering data for sericite 163–165 39K, neutron bombardment 33 study using 40Ar/39Ar 5 39K/Ar dating technique 1 laser heating/ablation 39K/40K ratio 11 benefits of technique 351 39K/41K ratio 10–11 history of use 79 40K new developments 79–80 abundance 10, 15, 16 scanning laser technology 80 atomic weight 10 system performance 88–89 calculation of mineral content 167–168 system tests daughter isotopes 10, 10 blanks 84–86 decay constant 10 burn patterns 80–81 decay scheme 12 rastering 86–87 half life 10 step-heating 82–84 40K/Ar*, mineral standards 63 laser depth-profiling 137, 138, 266 40K/39Ar dating technique 1 application to Ar diffusion and solubility applications 9 measurement assumptions to be fulfilled 12–13 methods igneous rocks 10 samples 138 primary standards 53 sample treatment 138, 143 K feldspar modelling 143–144 Ar retention compared with plagioclase 147 results 140, 141, 142, 144–146 diffusion styles 265 results discussed Gangdiseˆ feldspar 110–111 diffusion 146–148 laboratory degassing 108–109 solubility 148–152 Madagascar sanidine 112 lasers microtextures and temperature 107 application to noble gas extraction 3 see also adularia; orthoclase; sanidine role in fusing crystals 14 Karelian Province, source of hornblende 247, 247 Late Heavy Bombardment (LHB) studies 102 Karin family 339 lattice diffusion 137, 265 Karoo Magmatic Province 159, 162, 163 Laurentide Ice Sheet age of sericitization 171 Heinrich events 245, 254, 257–260 Kilimanjaro obsidian, dating 88, 88 lavas, ascent rate calculations 147 krypton (Kr) Lesotho lavas, dating 163 subducting slab release 181 Lesser Antilles magmatic arc see Bouillante various isotopes geothermal field 78Kr, cosmic ray induction 175–176 liquid scintillation counting (LSC) 16, 22 INDEX 373

Lonar crater 349 Meliata Ocean 208 Lone Grove pluton hornblende 35 melting and impact craters 333 experiment to test 37Ar recoil Meridional Overturning Circulation (MOC) 254 method 36 Messadit section (Morocco) 18 results 39, 40, 40, 41, 42 metamorphism, dating low grade 157, 165–166 results discussed 47 meteorites Los Angeles basaltic shergottite chondrites experiment to test argon age 303, 304 40Ar/39Ar dating isochron plots 303–307 H type 339–341 nature of trapped argon 307–309 L type 336–339 lunar crater dating 176 LL type 341–343 lunar maria, problems of dating 155 problems associated 334–336 lunar rock samples, dating 176–177 summary of age data 343 classification 333 McLean pluton, dating 24 cosmic-ray induced noble gases 175 Madagascar cosmogenic exposure 4, 175 gem feldspar (Itrongay) 193 dating by I-Xe 178 age 266 3He concentration 176 description 266 role of 40Ar/39Ar 4 diffusion study see also Mars methods of analysis metrological standard, defined 69 laser ablation 267–268 Mianlue suture 190 sample preparation 266–267 mica standards see biotite; muscovite results 268–270 microlites, problem of 351 results discussed 270–272 microtexture see texture summary of model 272–273 mineral standards history of research 266 defined 63 sanidine 112 importance of 2–3 Main Asteroid Belt 333 for neutron flux determination 63 Main Central Thrust (Himalaya), muscovite testing thermochronology 98 see biotite; hornblende; muscovite; plagioclase; mantle (upper), study of volatiles 175 sanidine Mars mineralization dating 178–179, 180–183 application of 40Ar/39Ar 4 Mississippi Valley Type (MVT) mineralization dating argon sources 299–300 179, 180–181, 182 resolution of components 300–303 model cooling history (MCH) method 194–195 Los Angeles basaltic shergottite modelling experiment to test argon age 303, 304 diffusion 109 isochron plots 303–307 diffusivity and solubility 143–144 nature of trapped argon 307–309 effect of sericitization 157–160 meteorites mixing 123–126 ages 297, 298, 312–313 multi-diffusion domains see under multi-diffusion classification 297, 311 domain (MDD) exposure to cosmic rays 300 multi-path (MP) diffusion see multi-path monitoring 176 diffusion shergottite NWA4797 shock melting study 318, thermal history 272–273 318–319 monazite age, Dabie Mountains 191 methods of analysis moon rock dating 176–177 40Ar/39Ar recording 321–323 Morocco, astronomically tuned sections 18 sample preparation 320–321 multi-diffusion domain (MDD) or multi-domain microscope images 320 diffusion (MDD) petrography 319–320 analysis 117 results modelling 266 calculated CRE age 325–327 model future groundmass 323 extra-terrestrial material 102 plagioclase grains 324–325 K–Ar thermochronology 98–99 vein 323–324 K–Ca thermochronology 99–102 results discussed 327–330 model merits 95–96 mass spectrometer model shortcomings 96–98 calibration 14–15 relation to cooling history 190, 193 pioneering design 9 theory 92–95 mathematical modelling see modelling multi-path (MP) diffusion 190, 193, 265 Matuyama-Brunhes (MB) boundary, multibeam collection 14 age 18, 26, 28 multiplier detectors 14 374 INDEX muscovite results 250–252 age standard B4M and petrological suitability 69 results discussed 253–254 K–Ar age 69 hornblende provenances 247–248 Rb–Sr age 69 North Atlantic ice-rafting events 245 checks for petrological equilibrium North Carolina (USA), oligoclase samples 138 methods of analysis North China Block 190, 190 40Ar/39Ar step heating 70 North Pennine orefield, mineralization EMP 70 dating 179 Rb-Sr 70 Northern Calcareous Alps size separation 70 orogenic history 208 XRD 70 palaeotemperature and age analysis results history of research 210, 210 Rb–Sr 70–71 methods 210–211 SMP 72–74, 73 results XRD 71–72, 72 40Ar/39Ar dates 215, 216, 217, 218–219 results discussed 74–77 illite crystallinity 219 K–Ar thermochronology with MDD model 98–99 rock descriptions 211–212, 215 K–Ca thermochronology with MDD model thin sections 213, 214 99–102 vitrinite reflectance 219 phengite muscovite and Ar diffusion 117–118 results discussed 220–221 Arrhenius data 121–123 results fluid inclusion analysis 219–220 Arrhenius data inversion 126–130 salt mines 208–209 modelling mixing 123–126 setting 208, 209 pressure effects 130–133 step-heating observations 118–121 obsidian, dating of Kilimanjaro sample 88, 88 summary 133–134 oceanic island basalts, problems of dating 155 oligoclase nakhlites 297, 311, 317 Ar solubility and diffusion measurement 138 21Ne, cosmic ray induction 175–176 methods 21Ne/22Ne ratio, spectral hardness 176 samples 138 near-surface diffusion pathway 137 sample treatment 138, 143 neutron absorption, by halogens 178–179 modelling 143–144 neutron activation 3, 178–179 results 140, 141, 142, 144–146 neutron capture 337 results discussed neutron dose (J value) 2–3 diffusion 146–148 neutron fluence, interference from Ca and Cl 177 solubility 148–152 neutron fluence monitor, FCs 63 optimization approach to calibration neutron flux, determination 63 future 29 neutron induced 37Ar recoil misrepresentation 25–26 causes of 351 misuse 24–25 effects of 34–35 practicalities 21–22 experiment to test use 22–23 methods 35–36 optimization model 3 results 36–40 orbital tuning 23–24 results discussed ore deposits age correction 48–49 dating 157 comparison with theory 47–48 dating using saline fluids 175 Fish Canyon plagioclase 40, 43–46 orogenesis, studies using 40Ar/39Ar 4 hornblende Hb3gr 47 orthoclase (Itrongay feldspar; low sanidine/orthoclase) summary of implications 49–51 age 266 neutron irradiation description 266 production of isotopes 3–4, 33, 53 diffusion study use of vacuum encapsulation 54 methods of analysis New Mexico (USA) laser ablation 267–268 polyhalite studies 207–208 sample preparation 266–267 labradorite samples 138 results 268–270 New Zealand, gold-bearing veins and fluid inclusion results discussed 270–272 dating 180 summary of model 272–273 Ningqiang meteorite 183 history of research 266 noble gas yields by cosmic rays 175–176 orthopyroxenite breccia, Martian 297, 311, 317 North Atlantic Deep Water (NADW) 254 outgassing rate, Earth 179 North Atlantic ice-rafting detritus (IRD) oxygen isotope studies hornblende provenance study Heinrich events 246, 253, 254, 255 methods of analysis 248–250 Martian meteorites 297 INDEX 375 patch perthite, role in diffusion 265 potassium (K) Pb/Pb dating, shergottites 318 abundance 1 perthite style, effect on diffusion 265 role in dating 1, 3 phengite muscovite and Ar diffusion 117–118 various isotopes see under K Arrhenius data 121–123 pressure impact on diffusion 130–133 Arrhenius data inversion 126–130 primary standards modelling mixing 123–126 defined 53, 63 pressure effects 130–133 recoil testing step-heating observations 118–121 method 55–56 summary 133–134 results 56, 56 phonon results discussed 56–61 defined 108 production ratios 13 role in diffusion 108 provenance studies, role of 40Ar/39Ar 4–5 Pilbara greenstone (Australia), muscovite hornblende age and provenance 245, 253–254 thermochronology 100 sources in ice-rafted detritus 247–248 plagioclase Pueblo Park, New Mexico, labradorite samples 138 Ar retention compared with K feldspar 147 pumpelleyite facies, dating 165–166 dating 137 pyroxene in Martian orthopyroxenite 297, in shock melted shergottite 318 311, 317 handling alteration to sericite 155, 156, 157 pyroxenite, deuteric alteration age 179–180 calculating 40K 168 detection, using degassing curves 161–162 Qinling granitoids 191 determining time of 162–163 Qinling Mountains 190 effects on mineral age Qinling–Dabie Orogenic Belt 189 mathematical modelling 157–158 geological setting 190–191 age reduction calculation 158–160 granitoid chronology plagioclase composition 159 methods time factor 159 model cooling history (MCH) 194–195 petrology 157 sampling 191, 192, 193 solubility and diffusion in labradorite and thermal model 193 oligoclase results methods geochronology 192, 195–197 experimental techniques 138, 143 thermochronology 198–200 sample description 138 significance of results 200–203 modelling 143–144 Qinling–Tongbai orogen 189 results 144–146 quality of samples, importance of 2 results discussed diffusion 146–148 R value, defined 63–64 solubility 148–152 Rajahmundry traps 160, 162 standard minerals raster tests, CO2 laser method 86–87 Fish Canyon plagioclase (FCp) 35 Rb–Sr isotopic age experiment to test 37Ar recoil B4M muscovite 69, 70,71 methods 35–36 Dabie Mountains 191 results 36, 37, 38,39 shergottites 318 results discussed 40, 43–46 recoil of 37Ar see also shergottites, NWA4797 causes of 351 plateau, defined 2 effects of 34–35 plateau plot 334 experiment to test Pleistocene lava, ascent rate calculations 147 methods 35–36 pollen analysis, relation to Heinrich events 255–257 results 36–40 polyhalite, Alpine 207 results discussed crystallization and recrystallization age correction 48–49 methods of analysis 210–211 comparison with theory 47–48 results Fish Canyon plagioclase 40, 43–46 40Ar/39Ar dates 215, 216, 217, 218–219 hornblende Hb3gr 47 fluid inclusion analysis 219 summary of implications 49–51 illite crystallinity 219 explained 3 rock descriptions 211–212, 215 problems of 33, 53, 299 thin sections 213, 214 quantification 34 vitrinite reflectance 219 recoil distance 54 results discussed 220–221 recoil testing with vacuum encapsulation 54 as geochronometer 207 method 55–56 history of dating research 207–208 results 56, 56 rheology 207 results discussed 56–61 376 INDEX recrystallization sericitization 155, 156, 157 role in geochronometers 107 calculating 40K 168 water-assisted 107 detection, using degassing curves 161–162 Reichenhall Formation 208 determining time of 162–163 relative probability plots 335 effects on mineral age Reynolds, J. H., early work 9 mathematical modelling 157–158 Rhynie chert, fluid inclusions 179 age reduction calculation 158–160 Rochechouart impact 349 plagioclase composition 159 Rutherford backscattering 137 time factor 159 petrology 157 36S Shangdan suture 190 in meteorites 175 shergottites 297, 311, 317, 318 in sodalite 183 Los Angeles basaltic Salado Formation 207 experiment to test argon age 303, 304 saline fluid and ore mineral dating 175, 178–179 isochron plots 303–307 San Juan volcanic field, as source of mineral standard 63 nature of trapped argon 307–309 Sanbagawa metamorphic belt, fluid inclusion NWA4797 shock melting study 318, 318–319 studies 181 methods of analysis sanidine 40Ar/39Ar recording 321–323 Fish Canyon (FCs) sample preparation 320–321 age 3, 16, 17–18, 21, 26 microscope images 320 correlation to orbital tuning 23 petrography 319–320 as mineral standard 63 results experiments to test calculated CRE age 325–327 40Ar/39Ar technique 65–66 groundmass 323 methods 64–65 plagioclase grains 324–325 results 65,66 vein 323–324 vacuum encapsulation technique 54 results discussed 327–330 recoil test method 55–56 problems of argon components 300–303 results 56, 56 problems of dating 297, 298, 299 results discussed 56–61 radioisotopic ages 318 Madagascar 112 shock deformation and impact craters 318, 333 mineral standards (FCT-3; TCR-2) problems in 40Ar/39Ar dating 334–335 recoil testing shock melting in shergottite 318 method 55–56 see shergottite, NWA4797 results 56, 56 shock metamorphism in meteorites 317 results discussed 56–61 induced melting 318 recoil-induced loss 34 Siberian traps, plagioclase dating problems see also K feldspar; orthoclase 159, 162 Sa˜o Tome´ basalt 86, 87 silicon, diffusion in 108–109 scanning laser technology size of grain initial development 79 effect on recoil 33, 53–54 limitations 79 effect on standard mineral see muscovite B4M new developments 80 effect on thermochronology 98 description 80, 81 impact on Arrhenius diagrams 109 system performance 88–89 Skiddaw granite, dating 179 system tests Sm-Nd mineral dating blanks 84–86 Dabie Mountains 191 burn patterns 80–81 Martian meteorites 297, 298, 312–313 rastering 86–87 shergottites 318 step-heating 82–84 smectite, special techniques for dating 54 Schmeissneria sodalite as an early angiosperm 277–278 36Cl study 177–178 40Ar/39Ar dating of first appearance 36S 183 methods, sampling 279–280 solar flare protons, role in Ar isotope production methods laboratory procedure 280 176, 177 results 281 solubility results discussed 281–282 measurement of Ar in labradorite and oligoclase 138 secondary standards methods defined 53, 63 sample preparation 138 recoil testing techniques 138, 143 method 55–56 model 143–144 results 56, 56 results 144–146 results discussed 56–61 results discussed 148–152 INDEX 377

South China Block 190, 190 tectonic studies, role of 40Ar/39Ar 4 Southern Alps, gold-bearing veins and fluid inclusion tectonothermal history and thermochronology 225 dating 180 Eastern Alaska Range spectral hardness and 21Ne/22Ne 176 early research 226 Stac Fada ejecta blanket 349 exhumation history staircase age spectrum, K feldspar 190, 193, 194 methods of analysis standard, defined 69 laboratory techniques 228–230 for neutron flux determination 63 multi-domain diffusion model 230–231, 233 primary v. secondary 53, 63 sampling 227, 228 standard minerals results importance of accurate ages 21 biotite ages 233–235 importance of 2–3 feldspar age constraints 235 recoil testing feldspar MDD thermal models 232, method 55–56 235–236 results 56, 56 results discussed 236–239 results discussed 56–61 geological setting 226, 227–228 testing temperature see Fish Canyon sanidine; Fish Canyon plagioclase; relation to diffusion rate 265 hornblende; muscovite B4M role in Ar component release 82–83 statistical optimization approach to calibration 21 role in Ar solubility in plagioclase 151 future 29 role in geochronometers 107 misrepresentation 25–26 temperature-time history 91, 225 misuse 24–25 role of 40Ar/39Ar 4 practicalities 21–22 terrestrial impact record 349 use 22–23 texture and microtexture, temperature step-heating effects 107 applications thermal history interpretation 91 chondrite meteorites 334 role of Fickian diffusion 109 Dellen impact structure 351, 356, 358 use of K/Ar 9 exhumation studies 230, 231 thermal neutrons Haifanggoui Formation studies 280, 281 capture 335, 337 muscovite age standard 70 fluence 13 phengite muscovite diffusion study 117, 118–121 thermochronology 91 polyhalite studies 215, 217 Itrongay feldspar CO2 laser testing 83–84 age 266 theory of 82–83, 91–92 description 266 subduction-related fluid inclusion analysis 181 diffusion study suevite 352 methods of analysis Superior Province, source of hornblende 247, 247 laser ablation 267–268 Susong metamorphic complex 191 sample preparation 266–267 Svecoffenian Province, source of hornblende 247, 247 results 268–270 Sveconorwegian Province, source of hornblende 247, 247 results discussed 270–272 Sweden, Dellen impact crater, glass age study summary of model 272–273 description 352 history of research 266 geological setting 350, 351–352 muscovite methods of study K–Ar muscovite 98–99 40Ar/39Ar dating 354, 356 K–Ca muscovite 99–102 electron microprobe 354 muscovite B4M 69–70 FT-IR spectroscopy 354 orogen studies 225 hydrogen isotope analysis 354 Eastern Alaska Range 226, 227–228 optical microscopy 353 early research 226 Raman spectroscopy 354 exhumation history SEM 352, 354 methods of analysis previous age research 351, 352 laboratory techniques 228–230 petrography 356–357 multi-domain diffusion model results 230–231, 233 40Ar/39Ar date 358–359 sampling 227, 228 composition 355 results trapped water 357 biotite ages 233–235 results discussed feldspar age constraints 235 inherited argon 360–362 feldspar MDD thermal models 232, perthitic texture 359–360 235–236 water history 360 results discussed 236–239 significance of results 362–363 Qinling Dabie Orogen 189, 190–191 378 INDEX thermochronology (Continued) results 56, 56 granitoid chronology results discussed 56–61 methods Vesuvius eruption products in dating 16 model cooling history (MCH) 194–195 vitrinite reflectance sampling 191, 192, 193 Northern Calcareous Alps, Haselgebirge Formation thermal model 193 methods 211 results results 219 geochronology 192, 195–197 volcanic events and rocks thermochronology 198–200 40Ar/39Ar dating 5, 137 significance of results 200–203 use of adularia breccia 288, 291 thermochronometry, use of K/Ar 9 methods 291 Tiaojishan Formation see Lanqi Formation results 289, 290, 291–292 time-temperature history 91, 225 results discussed 292–293 role of 40Ar/39Ar 4 ascent rate calculations 147 Togni Quarry (Brione), source for age standard 69 basaltic, problems of dating 155 Tristan da Cunha basalt, dating 88, 88, 182–183 Vesuvius AD79 16 tungsten, dating of mineralization 178–179 tweed perthite, role in diffusion 265 wadalite, S36 183 water-assisted recrystallization 107 U–Pb methods 21 water-rock reactions see hydrothermal systems age of shergottites 318 40 39 paired with Ar/ Ar for statistical optimization 21 x0 value 34 zircon ages Xe, various isotopes 181 Bishop Tuff 26, 28 cosmic ray induction 175–176 comparisons 16 Xingxueanthus Dabie Mountains 191 as an early angiosperm 277–278 Eastern Alaska Range 228 40Ar/39Ar dating of first appearance McLean pluton 24 methods, sampling 279–280 U/Th–He 333, 337 methods laboratory procedure 280 UV laser ablation 137 results 281 Ar release by 83 results discussed 281–282 UV laser depth-profiling 137, 138, 266 XRD, muscovite B4M 70, 71–72 application to Ar diffusion and solubility measurement methods Yakutat microplate 226, 226, 227 samples 138 impact on Eastern Alaska Range 238–239 sample treatment 138, 143 Yangtze blueschist belt 191 modelling 143–144 results 140, 141, 142, 144–146 Zagami meteorite 297, 299 results discussed Zaire cubes, dating 180 diffusion 146–148 zeolite facies, dating 165–166 solubility 148–152 zinc windows for laser work 79, 80 UV laser microprobe spot analyses 319, 334 zircon age with U–Pb, comparisons 16 Bishop Tuff 26, 28 vacuum encapsulation 54 Dabie Mountains 191 use in recoil testing Eastern Alaska Range 228 method 55–56 McLean pluton 24