Constraints on plateau architecture and assembly from deep crustal xenoliths, northern Altiplano (SE Peru)
Newly discovered xenoliths within Pliocene and Quaternary intermediate volcanic rocks from southern Peru permit examination of lithospheric processes by which thick crust (60-70 km) and high average elevations (3-4 km) resulted within the Altiplano, the second most extensive orogenic plateau on Eart...
Ausführliche Beschreibung
Gespeichert in:
| Autor*in: |
Alan D Chapman [verfasserIn] |
|---|
| Format: |
Artikel |
|---|---|
| Sprache: |
Englisch |
| Erschienen: |
2015 |
|---|
| Rechteinformationen: |
Nutzungsrecht: © COPYRIGHT 2015 Geological Society of America, Inc. |
|---|
| Schlagwörter: |
|---|
| Übergeordnetes Werk: |
Enthalten in: Geological Society of America bulletin - Boulder, Colo. [u.a.] : Geological Society of America, 1890, 127(2015), 11-12, Seite 1777-1797 |
|---|---|
| Übergeordnetes Werk: |
volume:127 ; year:2015 ; number:11-12 ; pages:1777-1797 |
| Links: |
|---|
| DOI / URN: |
10.1130/B31206.1 |
|---|
| Katalog-ID: |
OLC1968145478 |
|---|
| LEADER | 01000caa a2200265 4500 | ||
|---|---|---|---|
| 001 | OLC1968145478 | ||
| 003 | DE-627 | ||
| 005 | 20220217014102.0 | ||
| 007 | tu | ||
| 008 | 160206s2015 xx ||||| 00| ||eng c | ||
| 024 | 7 | |a 10.1130/B31206.1 |2 doi | |
| 028 | 5 | 2 | |a PQ20160617 |
| 035 | |a (DE-627)OLC1968145478 | ||
| 035 | |a (DE-599)GBVOLC1968145478 | ||
| 035 | |a (PRQ)c1670-28682ef8dcc5db5634300e66a5e1da5e0c00fdd17de39992c96f89d3c3cdec270 | ||
| 035 | |a (KEY)0093391020150000127001101777constraintsonplateauarchitectureandassemblyfromdee | ||
| 040 | |a DE-627 |b ger |c DE-627 |e rakwb | ||
| 041 | |a eng | ||
| 082 | 0 | 4 | |a 550 |q DNB |
| 100 | 0 | |a Alan D Chapman |e verfasserin |4 aut | |
| 245 | 1 | 0 | |a Constraints on plateau architecture and assembly from deep crustal xenoliths, northern Altiplano (SE Peru) |
| 264 | 1 | |c 2015 | |
| 336 | |a Text |b txt |2 rdacontent | ||
| 337 | |a ohne Hilfsmittel zu benutzen |b n |2 rdamedia | ||
| 338 | |a Band |b nc |2 rdacarrier | ||
| 520 | |a Newly discovered xenoliths within Pliocene and Quaternary intermediate volcanic rocks from southern Peru permit examination of lithospheric processes by which thick crust (60-70 km) and high average elevations (3-4 km) resulted within the Altiplano, the second most extensive orogenic plateau on Earth. The most common petrographic groups of xenoliths studied here are igneous or meta-igneous rocks with radiogenic isotopic ratios consistent with recent derivation from asthenospheric mantle (...Sr/...Sr = 0.704-0.709, ...Nd/...Nd = 0.5126-0.5129). A second group, consisting of felsic granulite xenoliths exhibiting more radiogenic compositions (...Sr/...Sr = 0.711-0.782, ...Nd/...Nd = 0.5121-0.5126), is interpreted as supracrustal rocks that underwent metamorphism at ~9 kbar (~30-35 km paleodepth, assuming a mean crustal density of 2.8 g/cm...) and ~750 ...C. These rocks are correlated with nonmetamorphosed rocks of the Mitu Group and assigned a Mesozoic (Upper Triassic or younger) age based on detrital zircon U-Pb ages. A felsic granulite Sm-Nd garnet whole-rock isochron of 42 ± 2 Ma demonstrates that garnet growth took place in Eocene time. Monazite grains associated with quenched anatectic melt networks in the same rocks yield ion microprobe U-Pb ages ranging from 3.2 ± 0.2 to 4.4 ± 0.3 Ma (2...). These disparate geochronologic data sets are reconciled by a model wherein Mesozoic cover rocks were transferred to >30 km depth beneath the plateau in the Eocene and progressively heated until at least Pliocene time. Isothermal decompression and partial melting ensued as these rocks were entrained as xenoliths in volcanic host magmas and transported toward the surface. Mafic granulites and peridotites from the same xenolith suite comprise the basement of the metasedimentary sequence, exhibiting isotopic characteristics of Central Andean crust. Calculated equilibrium pressures for these basement rocks are >11 kbar, suggesting that the basement-cover interface lies beneath the northernmost Altiplano at ~30-40 km below the surface. Together, these results indicate that crustal thickening under the northernmost Altiplano started earlier than major latest Oligocene and Miocene uplift episodes affecting the region and was coeval with a flat slab-related regional episode of deformation. Total shortening must have been at least 20% more than previous estimates in order to satisfy the basement to cover depth constraints provided by the xenolith data. Sedimentary rocks at >30 km paleodepth require that Andean basement thrusts decapitated earlier Triassic normal faults, trapping Paleozoic and Mesozoic rocks below the main d...collement. Magma loading from intense Cenozoic plutonism within the plateau probably played an additional role in transporting Mesozoic cover rocks to >30 km and thickening the crust beneath the northern Altiplano. (ProQuest: ... denotes formulae/symbols omitted.) | ||
| 540 | |a Nutzungsrecht: © COPYRIGHT 2015 Geological Society of America, Inc. | ||
| 650 | 4 | |a Inclusions | |
| 650 | 4 | |a Earth | |
| 650 | 4 | |a Metamorphism (Geology) | |
| 650 | 4 | |a Rocks, Igneous | |
| 650 | 4 | |a Analysis | |
| 650 | 4 | |a Crust | |
| 650 | 4 | |a Lithosphere | |
| 650 | 4 | |a Igneous rock | |
| 650 | 4 | |a Geology | |
| 650 | 4 | |a Magma | |
| 650 | 4 | |a Deformation | |
| 700 | 0 | |a Mihai N Ducea |4 oth | |
| 700 | 0 | |a Nadine McQuarrie |4 oth | |
| 700 | 0 | |a Matthew Coble |4 oth | |
| 700 | 0 | |a Lucian Petrescu |4 oth | |
| 700 | 0 | |a Derek Hoffman |4 oth | |
| 773 | 0 | 8 | |i Enthalten in |t Geological Society of America bulletin |d Boulder, Colo. [u.a.] : Geological Society of America, 1890 |g 127(2015), 11-12, Seite 1777-1797 |w (DE-627)129067199 |w (DE-600)1351-1 |w (DE-576)014398621 |x 0016-7606 |7 nnns |
| 773 | 1 | 8 | |g volume:127 |g year:2015 |g number:11-12 |g pages:1777-1797 |
| 856 | 4 | 1 | |u http://dx.doi.org/10.1130/B31206.1 |3 Volltext |
| 856 | 4 | 2 | |u http://search.proquest.com/docview/1729122342 |
| 912 | |a GBV_USEFLAG_A | ||
| 912 | |a SYSFLAG_A | ||
| 912 | |a GBV_OLC | ||
| 912 | |a SSG-OLC-GEO | ||
| 912 | |a SSG-OPC-GGO | ||
| 912 | |a GBV_ILN_21 | ||
| 912 | |a GBV_ILN_22 | ||
| 912 | |a GBV_ILN_70 | ||
| 912 | |a GBV_ILN_188 | ||
| 912 | |a GBV_ILN_2010 | ||
| 912 | |a GBV_ILN_2027 | ||
| 912 | |a GBV_ILN_4046 | ||
| 912 | |a GBV_ILN_4112 | ||
| 912 | |a GBV_ILN_4323 | ||
| 951 | |a AR | ||
| 952 | |d 127 |j 2015 |e 11-12 |h 1777-1797 | ||
| author_variant |
a d c adc |
|---|---|
| matchkey_str |
article:00167606:2015----::osritopaeurhtcuenasmlfodecutleoih |
| hierarchy_sort_str |
2015 |
| publishDate |
2015 |
| allfields |
10.1130/B31206.1 doi PQ20160617 (DE-627)OLC1968145478 (DE-599)GBVOLC1968145478 (PRQ)c1670-28682ef8dcc5db5634300e66a5e1da5e0c00fdd17de39992c96f89d3c3cdec270 (KEY)0093391020150000127001101777constraintsonplateauarchitectureandassemblyfromdee DE-627 ger DE-627 rakwb eng 550 DNB Alan D Chapman verfasserin aut Constraints on plateau architecture and assembly from deep crustal xenoliths, northern Altiplano (SE Peru) 2015 Text txt rdacontent ohne Hilfsmittel zu benutzen n rdamedia Band nc rdacarrier Newly discovered xenoliths within Pliocene and Quaternary intermediate volcanic rocks from southern Peru permit examination of lithospheric processes by which thick crust (60-70 km) and high average elevations (3-4 km) resulted within the Altiplano, the second most extensive orogenic plateau on Earth. The most common petrographic groups of xenoliths studied here are igneous or meta-igneous rocks with radiogenic isotopic ratios consistent with recent derivation from asthenospheric mantle (...Sr/...Sr = 0.704-0.709, ...Nd/...Nd = 0.5126-0.5129). A second group, consisting of felsic granulite xenoliths exhibiting more radiogenic compositions (...Sr/...Sr = 0.711-0.782, ...Nd/...Nd = 0.5121-0.5126), is interpreted as supracrustal rocks that underwent metamorphism at ~9 kbar (~30-35 km paleodepth, assuming a mean crustal density of 2.8 g/cm...) and ~750 ...C. These rocks are correlated with nonmetamorphosed rocks of the Mitu Group and assigned a Mesozoic (Upper Triassic or younger) age based on detrital zircon U-Pb ages. A felsic granulite Sm-Nd garnet whole-rock isochron of 42 ± 2 Ma demonstrates that garnet growth took place in Eocene time. Monazite grains associated with quenched anatectic melt networks in the same rocks yield ion microprobe U-Pb ages ranging from 3.2 ± 0.2 to 4.4 ± 0.3 Ma (2...). These disparate geochronologic data sets are reconciled by a model wherein Mesozoic cover rocks were transferred to >30 km depth beneath the plateau in the Eocene and progressively heated until at least Pliocene time. Isothermal decompression and partial melting ensued as these rocks were entrained as xenoliths in volcanic host magmas and transported toward the surface. Mafic granulites and peridotites from the same xenolith suite comprise the basement of the metasedimentary sequence, exhibiting isotopic characteristics of Central Andean crust. Calculated equilibrium pressures for these basement rocks are >11 kbar, suggesting that the basement-cover interface lies beneath the northernmost Altiplano at ~30-40 km below the surface. Together, these results indicate that crustal thickening under the northernmost Altiplano started earlier than major latest Oligocene and Miocene uplift episodes affecting the region and was coeval with a flat slab-related regional episode of deformation. Total shortening must have been at least 20% more than previous estimates in order to satisfy the basement to cover depth constraints provided by the xenolith data. Sedimentary rocks at >30 km paleodepth require that Andean basement thrusts decapitated earlier Triassic normal faults, trapping Paleozoic and Mesozoic rocks below the main d...collement. Magma loading from intense Cenozoic plutonism within the plateau probably played an additional role in transporting Mesozoic cover rocks to >30 km and thickening the crust beneath the northern Altiplano. (ProQuest: ... denotes formulae/symbols omitted.) Nutzungsrecht: © COPYRIGHT 2015 Geological Society of America, Inc. Inclusions Earth Metamorphism (Geology) Rocks, Igneous Analysis Crust Lithosphere Igneous rock Geology Magma Deformation Mihai N Ducea oth Nadine McQuarrie oth Matthew Coble oth Lucian Petrescu oth Derek Hoffman oth Enthalten in Geological Society of America bulletin Boulder, Colo. [u.a.] : Geological Society of America, 1890 127(2015), 11-12, Seite 1777-1797 (DE-627)129067199 (DE-600)1351-1 (DE-576)014398621 0016-7606 nnns volume:127 year:2015 number:11-12 pages:1777-1797 http://dx.doi.org/10.1130/B31206.1 Volltext http://search.proquest.com/docview/1729122342 GBV_USEFLAG_A SYSFLAG_A GBV_OLC SSG-OLC-GEO SSG-OPC-GGO GBV_ILN_21 GBV_ILN_22 GBV_ILN_70 GBV_ILN_188 GBV_ILN_2010 GBV_ILN_2027 GBV_ILN_4046 GBV_ILN_4112 GBV_ILN_4323 AR 127 2015 11-12 1777-1797 |
| spelling |
10.1130/B31206.1 doi PQ20160617 (DE-627)OLC1968145478 (DE-599)GBVOLC1968145478 (PRQ)c1670-28682ef8dcc5db5634300e66a5e1da5e0c00fdd17de39992c96f89d3c3cdec270 (KEY)0093391020150000127001101777constraintsonplateauarchitectureandassemblyfromdee DE-627 ger DE-627 rakwb eng 550 DNB Alan D Chapman verfasserin aut Constraints on plateau architecture and assembly from deep crustal xenoliths, northern Altiplano (SE Peru) 2015 Text txt rdacontent ohne Hilfsmittel zu benutzen n rdamedia Band nc rdacarrier Newly discovered xenoliths within Pliocene and Quaternary intermediate volcanic rocks from southern Peru permit examination of lithospheric processes by which thick crust (60-70 km) and high average elevations (3-4 km) resulted within the Altiplano, the second most extensive orogenic plateau on Earth. The most common petrographic groups of xenoliths studied here are igneous or meta-igneous rocks with radiogenic isotopic ratios consistent with recent derivation from asthenospheric mantle (...Sr/...Sr = 0.704-0.709, ...Nd/...Nd = 0.5126-0.5129). A second group, consisting of felsic granulite xenoliths exhibiting more radiogenic compositions (...Sr/...Sr = 0.711-0.782, ...Nd/...Nd = 0.5121-0.5126), is interpreted as supracrustal rocks that underwent metamorphism at ~9 kbar (~30-35 km paleodepth, assuming a mean crustal density of 2.8 g/cm...) and ~750 ...C. These rocks are correlated with nonmetamorphosed rocks of the Mitu Group and assigned a Mesozoic (Upper Triassic or younger) age based on detrital zircon U-Pb ages. A felsic granulite Sm-Nd garnet whole-rock isochron of 42 ± 2 Ma demonstrates that garnet growth took place in Eocene time. Monazite grains associated with quenched anatectic melt networks in the same rocks yield ion microprobe U-Pb ages ranging from 3.2 ± 0.2 to 4.4 ± 0.3 Ma (2...). These disparate geochronologic data sets are reconciled by a model wherein Mesozoic cover rocks were transferred to >30 km depth beneath the plateau in the Eocene and progressively heated until at least Pliocene time. Isothermal decompression and partial melting ensued as these rocks were entrained as xenoliths in volcanic host magmas and transported toward the surface. Mafic granulites and peridotites from the same xenolith suite comprise the basement of the metasedimentary sequence, exhibiting isotopic characteristics of Central Andean crust. Calculated equilibrium pressures for these basement rocks are >11 kbar, suggesting that the basement-cover interface lies beneath the northernmost Altiplano at ~30-40 km below the surface. Together, these results indicate that crustal thickening under the northernmost Altiplano started earlier than major latest Oligocene and Miocene uplift episodes affecting the region and was coeval with a flat slab-related regional episode of deformation. Total shortening must have been at least 20% more than previous estimates in order to satisfy the basement to cover depth constraints provided by the xenolith data. Sedimentary rocks at >30 km paleodepth require that Andean basement thrusts decapitated earlier Triassic normal faults, trapping Paleozoic and Mesozoic rocks below the main d...collement. Magma loading from intense Cenozoic plutonism within the plateau probably played an additional role in transporting Mesozoic cover rocks to >30 km and thickening the crust beneath the northern Altiplano. (ProQuest: ... denotes formulae/symbols omitted.) Nutzungsrecht: © COPYRIGHT 2015 Geological Society of America, Inc. Inclusions Earth Metamorphism (Geology) Rocks, Igneous Analysis Crust Lithosphere Igneous rock Geology Magma Deformation Mihai N Ducea oth Nadine McQuarrie oth Matthew Coble oth Lucian Petrescu oth Derek Hoffman oth Enthalten in Geological Society of America bulletin Boulder, Colo. [u.a.] : Geological Society of America, 1890 127(2015), 11-12, Seite 1777-1797 (DE-627)129067199 (DE-600)1351-1 (DE-576)014398621 0016-7606 nnns volume:127 year:2015 number:11-12 pages:1777-1797 http://dx.doi.org/10.1130/B31206.1 Volltext http://search.proquest.com/docview/1729122342 GBV_USEFLAG_A SYSFLAG_A GBV_OLC SSG-OLC-GEO SSG-OPC-GGO GBV_ILN_21 GBV_ILN_22 GBV_ILN_70 GBV_ILN_188 GBV_ILN_2010 GBV_ILN_2027 GBV_ILN_4046 GBV_ILN_4112 GBV_ILN_4323 AR 127 2015 11-12 1777-1797 |
| allfields_unstemmed |
10.1130/B31206.1 doi PQ20160617 (DE-627)OLC1968145478 (DE-599)GBVOLC1968145478 (PRQ)c1670-28682ef8dcc5db5634300e66a5e1da5e0c00fdd17de39992c96f89d3c3cdec270 (KEY)0093391020150000127001101777constraintsonplateauarchitectureandassemblyfromdee DE-627 ger DE-627 rakwb eng 550 DNB Alan D Chapman verfasserin aut Constraints on plateau architecture and assembly from deep crustal xenoliths, northern Altiplano (SE Peru) 2015 Text txt rdacontent ohne Hilfsmittel zu benutzen n rdamedia Band nc rdacarrier Newly discovered xenoliths within Pliocene and Quaternary intermediate volcanic rocks from southern Peru permit examination of lithospheric processes by which thick crust (60-70 km) and high average elevations (3-4 km) resulted within the Altiplano, the second most extensive orogenic plateau on Earth. The most common petrographic groups of xenoliths studied here are igneous or meta-igneous rocks with radiogenic isotopic ratios consistent with recent derivation from asthenospheric mantle (...Sr/...Sr = 0.704-0.709, ...Nd/...Nd = 0.5126-0.5129). A second group, consisting of felsic granulite xenoliths exhibiting more radiogenic compositions (...Sr/...Sr = 0.711-0.782, ...Nd/...Nd = 0.5121-0.5126), is interpreted as supracrustal rocks that underwent metamorphism at ~9 kbar (~30-35 km paleodepth, assuming a mean crustal density of 2.8 g/cm...) and ~750 ...C. These rocks are correlated with nonmetamorphosed rocks of the Mitu Group and assigned a Mesozoic (Upper Triassic or younger) age based on detrital zircon U-Pb ages. A felsic granulite Sm-Nd garnet whole-rock isochron of 42 ± 2 Ma demonstrates that garnet growth took place in Eocene time. Monazite grains associated with quenched anatectic melt networks in the same rocks yield ion microprobe U-Pb ages ranging from 3.2 ± 0.2 to 4.4 ± 0.3 Ma (2...). These disparate geochronologic data sets are reconciled by a model wherein Mesozoic cover rocks were transferred to >30 km depth beneath the plateau in the Eocene and progressively heated until at least Pliocene time. Isothermal decompression and partial melting ensued as these rocks were entrained as xenoliths in volcanic host magmas and transported toward the surface. Mafic granulites and peridotites from the same xenolith suite comprise the basement of the metasedimentary sequence, exhibiting isotopic characteristics of Central Andean crust. Calculated equilibrium pressures for these basement rocks are >11 kbar, suggesting that the basement-cover interface lies beneath the northernmost Altiplano at ~30-40 km below the surface. Together, these results indicate that crustal thickening under the northernmost Altiplano started earlier than major latest Oligocene and Miocene uplift episodes affecting the region and was coeval with a flat slab-related regional episode of deformation. Total shortening must have been at least 20% more than previous estimates in order to satisfy the basement to cover depth constraints provided by the xenolith data. Sedimentary rocks at >30 km paleodepth require that Andean basement thrusts decapitated earlier Triassic normal faults, trapping Paleozoic and Mesozoic rocks below the main d...collement. Magma loading from intense Cenozoic plutonism within the plateau probably played an additional role in transporting Mesozoic cover rocks to >30 km and thickening the crust beneath the northern Altiplano. (ProQuest: ... denotes formulae/symbols omitted.) Nutzungsrecht: © COPYRIGHT 2015 Geological Society of America, Inc. Inclusions Earth Metamorphism (Geology) Rocks, Igneous Analysis Crust Lithosphere Igneous rock Geology Magma Deformation Mihai N Ducea oth Nadine McQuarrie oth Matthew Coble oth Lucian Petrescu oth Derek Hoffman oth Enthalten in Geological Society of America bulletin Boulder, Colo. [u.a.] : Geological Society of America, 1890 127(2015), 11-12, Seite 1777-1797 (DE-627)129067199 (DE-600)1351-1 (DE-576)014398621 0016-7606 nnns volume:127 year:2015 number:11-12 pages:1777-1797 http://dx.doi.org/10.1130/B31206.1 Volltext http://search.proquest.com/docview/1729122342 GBV_USEFLAG_A SYSFLAG_A GBV_OLC SSG-OLC-GEO SSG-OPC-GGO GBV_ILN_21 GBV_ILN_22 GBV_ILN_70 GBV_ILN_188 GBV_ILN_2010 GBV_ILN_2027 GBV_ILN_4046 GBV_ILN_4112 GBV_ILN_4323 AR 127 2015 11-12 1777-1797 |
| allfieldsGer |
10.1130/B31206.1 doi PQ20160617 (DE-627)OLC1968145478 (DE-599)GBVOLC1968145478 (PRQ)c1670-28682ef8dcc5db5634300e66a5e1da5e0c00fdd17de39992c96f89d3c3cdec270 (KEY)0093391020150000127001101777constraintsonplateauarchitectureandassemblyfromdee DE-627 ger DE-627 rakwb eng 550 DNB Alan D Chapman verfasserin aut Constraints on plateau architecture and assembly from deep crustal xenoliths, northern Altiplano (SE Peru) 2015 Text txt rdacontent ohne Hilfsmittel zu benutzen n rdamedia Band nc rdacarrier Newly discovered xenoliths within Pliocene and Quaternary intermediate volcanic rocks from southern Peru permit examination of lithospheric processes by which thick crust (60-70 km) and high average elevations (3-4 km) resulted within the Altiplano, the second most extensive orogenic plateau on Earth. The most common petrographic groups of xenoliths studied here are igneous or meta-igneous rocks with radiogenic isotopic ratios consistent with recent derivation from asthenospheric mantle (...Sr/...Sr = 0.704-0.709, ...Nd/...Nd = 0.5126-0.5129). A second group, consisting of felsic granulite xenoliths exhibiting more radiogenic compositions (...Sr/...Sr = 0.711-0.782, ...Nd/...Nd = 0.5121-0.5126), is interpreted as supracrustal rocks that underwent metamorphism at ~9 kbar (~30-35 km paleodepth, assuming a mean crustal density of 2.8 g/cm...) and ~750 ...C. These rocks are correlated with nonmetamorphosed rocks of the Mitu Group and assigned a Mesozoic (Upper Triassic or younger) age based on detrital zircon U-Pb ages. A felsic granulite Sm-Nd garnet whole-rock isochron of 42 ± 2 Ma demonstrates that garnet growth took place in Eocene time. Monazite grains associated with quenched anatectic melt networks in the same rocks yield ion microprobe U-Pb ages ranging from 3.2 ± 0.2 to 4.4 ± 0.3 Ma (2...). These disparate geochronologic data sets are reconciled by a model wherein Mesozoic cover rocks were transferred to >30 km depth beneath the plateau in the Eocene and progressively heated until at least Pliocene time. Isothermal decompression and partial melting ensued as these rocks were entrained as xenoliths in volcanic host magmas and transported toward the surface. Mafic granulites and peridotites from the same xenolith suite comprise the basement of the metasedimentary sequence, exhibiting isotopic characteristics of Central Andean crust. Calculated equilibrium pressures for these basement rocks are >11 kbar, suggesting that the basement-cover interface lies beneath the northernmost Altiplano at ~30-40 km below the surface. Together, these results indicate that crustal thickening under the northernmost Altiplano started earlier than major latest Oligocene and Miocene uplift episodes affecting the region and was coeval with a flat slab-related regional episode of deformation. Total shortening must have been at least 20% more than previous estimates in order to satisfy the basement to cover depth constraints provided by the xenolith data. Sedimentary rocks at >30 km paleodepth require that Andean basement thrusts decapitated earlier Triassic normal faults, trapping Paleozoic and Mesozoic rocks below the main d...collement. Magma loading from intense Cenozoic plutonism within the plateau probably played an additional role in transporting Mesozoic cover rocks to >30 km and thickening the crust beneath the northern Altiplano. (ProQuest: ... denotes formulae/symbols omitted.) Nutzungsrecht: © COPYRIGHT 2015 Geological Society of America, Inc. Inclusions Earth Metamorphism (Geology) Rocks, Igneous Analysis Crust Lithosphere Igneous rock Geology Magma Deformation Mihai N Ducea oth Nadine McQuarrie oth Matthew Coble oth Lucian Petrescu oth Derek Hoffman oth Enthalten in Geological Society of America bulletin Boulder, Colo. [u.a.] : Geological Society of America, 1890 127(2015), 11-12, Seite 1777-1797 (DE-627)129067199 (DE-600)1351-1 (DE-576)014398621 0016-7606 nnns volume:127 year:2015 number:11-12 pages:1777-1797 http://dx.doi.org/10.1130/B31206.1 Volltext http://search.proquest.com/docview/1729122342 GBV_USEFLAG_A SYSFLAG_A GBV_OLC SSG-OLC-GEO SSG-OPC-GGO GBV_ILN_21 GBV_ILN_22 GBV_ILN_70 GBV_ILN_188 GBV_ILN_2010 GBV_ILN_2027 GBV_ILN_4046 GBV_ILN_4112 GBV_ILN_4323 AR 127 2015 11-12 1777-1797 |
| allfieldsSound |
10.1130/B31206.1 doi PQ20160617 (DE-627)OLC1968145478 (DE-599)GBVOLC1968145478 (PRQ)c1670-28682ef8dcc5db5634300e66a5e1da5e0c00fdd17de39992c96f89d3c3cdec270 (KEY)0093391020150000127001101777constraintsonplateauarchitectureandassemblyfromdee DE-627 ger DE-627 rakwb eng 550 DNB Alan D Chapman verfasserin aut Constraints on plateau architecture and assembly from deep crustal xenoliths, northern Altiplano (SE Peru) 2015 Text txt rdacontent ohne Hilfsmittel zu benutzen n rdamedia Band nc rdacarrier Newly discovered xenoliths within Pliocene and Quaternary intermediate volcanic rocks from southern Peru permit examination of lithospheric processes by which thick crust (60-70 km) and high average elevations (3-4 km) resulted within the Altiplano, the second most extensive orogenic plateau on Earth. The most common petrographic groups of xenoliths studied here are igneous or meta-igneous rocks with radiogenic isotopic ratios consistent with recent derivation from asthenospheric mantle (...Sr/...Sr = 0.704-0.709, ...Nd/...Nd = 0.5126-0.5129). A second group, consisting of felsic granulite xenoliths exhibiting more radiogenic compositions (...Sr/...Sr = 0.711-0.782, ...Nd/...Nd = 0.5121-0.5126), is interpreted as supracrustal rocks that underwent metamorphism at ~9 kbar (~30-35 km paleodepth, assuming a mean crustal density of 2.8 g/cm...) and ~750 ...C. These rocks are correlated with nonmetamorphosed rocks of the Mitu Group and assigned a Mesozoic (Upper Triassic or younger) age based on detrital zircon U-Pb ages. A felsic granulite Sm-Nd garnet whole-rock isochron of 42 ± 2 Ma demonstrates that garnet growth took place in Eocene time. Monazite grains associated with quenched anatectic melt networks in the same rocks yield ion microprobe U-Pb ages ranging from 3.2 ± 0.2 to 4.4 ± 0.3 Ma (2...). These disparate geochronologic data sets are reconciled by a model wherein Mesozoic cover rocks were transferred to >30 km depth beneath the plateau in the Eocene and progressively heated until at least Pliocene time. Isothermal decompression and partial melting ensued as these rocks were entrained as xenoliths in volcanic host magmas and transported toward the surface. Mafic granulites and peridotites from the same xenolith suite comprise the basement of the metasedimentary sequence, exhibiting isotopic characteristics of Central Andean crust. Calculated equilibrium pressures for these basement rocks are >11 kbar, suggesting that the basement-cover interface lies beneath the northernmost Altiplano at ~30-40 km below the surface. Together, these results indicate that crustal thickening under the northernmost Altiplano started earlier than major latest Oligocene and Miocene uplift episodes affecting the region and was coeval with a flat slab-related regional episode of deformation. Total shortening must have been at least 20% more than previous estimates in order to satisfy the basement to cover depth constraints provided by the xenolith data. Sedimentary rocks at >30 km paleodepth require that Andean basement thrusts decapitated earlier Triassic normal faults, trapping Paleozoic and Mesozoic rocks below the main d...collement. Magma loading from intense Cenozoic plutonism within the plateau probably played an additional role in transporting Mesozoic cover rocks to >30 km and thickening the crust beneath the northern Altiplano. (ProQuest: ... denotes formulae/symbols omitted.) Nutzungsrecht: © COPYRIGHT 2015 Geological Society of America, Inc. Inclusions Earth Metamorphism (Geology) Rocks, Igneous Analysis Crust Lithosphere Igneous rock Geology Magma Deformation Mihai N Ducea oth Nadine McQuarrie oth Matthew Coble oth Lucian Petrescu oth Derek Hoffman oth Enthalten in Geological Society of America bulletin Boulder, Colo. [u.a.] : Geological Society of America, 1890 127(2015), 11-12, Seite 1777-1797 (DE-627)129067199 (DE-600)1351-1 (DE-576)014398621 0016-7606 nnns volume:127 year:2015 number:11-12 pages:1777-1797 http://dx.doi.org/10.1130/B31206.1 Volltext http://search.proquest.com/docview/1729122342 GBV_USEFLAG_A SYSFLAG_A GBV_OLC SSG-OLC-GEO SSG-OPC-GGO GBV_ILN_21 GBV_ILN_22 GBV_ILN_70 GBV_ILN_188 GBV_ILN_2010 GBV_ILN_2027 GBV_ILN_4046 GBV_ILN_4112 GBV_ILN_4323 AR 127 2015 11-12 1777-1797 |
| language |
English |
| source |
Enthalten in Geological Society of America bulletin 127(2015), 11-12, Seite 1777-1797 volume:127 year:2015 number:11-12 pages:1777-1797 |
| sourceStr |
Enthalten in Geological Society of America bulletin 127(2015), 11-12, Seite 1777-1797 volume:127 year:2015 number:11-12 pages:1777-1797 |
| format_phy_str_mv |
Article |
| institution |
findex.gbv.de |
| topic_facet |
Inclusions Earth Metamorphism (Geology) Rocks, Igneous Analysis Crust Lithosphere Igneous rock Geology Magma Deformation |
| dewey-raw |
550 |
| isfreeaccess_bool |
false |
| container_title |
Geological Society of America bulletin |
| authorswithroles_txt_mv |
Alan D Chapman @@aut@@ Mihai N Ducea @@oth@@ Nadine McQuarrie @@oth@@ Matthew Coble @@oth@@ Lucian Petrescu @@oth@@ Derek Hoffman @@oth@@ |
| publishDateDaySort_date |
2015-01-01T00:00:00Z |
| hierarchy_top_id |
129067199 |
| dewey-sort |
3550 |
| id |
OLC1968145478 |
| language_de |
englisch |
| fullrecord |
<?xml version="1.0" encoding="UTF-8"?><collection xmlns="http://www.loc.gov/MARC21/slim"><record><leader>01000caa a2200265 4500</leader><controlfield tag="001">OLC1968145478</controlfield><controlfield tag="003">DE-627</controlfield><controlfield tag="005">20220217014102.0</controlfield><controlfield tag="007">tu</controlfield><controlfield tag="008">160206s2015 xx ||||| 00| ||eng c</controlfield><datafield tag="024" ind1="7" ind2=" "><subfield code="a">10.1130/B31206.1</subfield><subfield code="2">doi</subfield></datafield><datafield tag="028" ind1="5" ind2="2"><subfield code="a">PQ20160617</subfield></datafield><datafield tag="035" ind1=" " ind2=" "><subfield code="a">(DE-627)OLC1968145478</subfield></datafield><datafield tag="035" ind1=" " ind2=" "><subfield code="a">(DE-599)GBVOLC1968145478</subfield></datafield><datafield tag="035" ind1=" " ind2=" "><subfield code="a">(PRQ)c1670-28682ef8dcc5db5634300e66a5e1da5e0c00fdd17de39992c96f89d3c3cdec270</subfield></datafield><datafield tag="035" ind1=" " ind2=" "><subfield code="a">(KEY)0093391020150000127001101777constraintsonplateauarchitectureandassemblyfromdee</subfield></datafield><datafield tag="040" ind1=" " ind2=" "><subfield code="a">DE-627</subfield><subfield code="b">ger</subfield><subfield code="c">DE-627</subfield><subfield code="e">rakwb</subfield></datafield><datafield tag="041" ind1=" " ind2=" "><subfield code="a">eng</subfield></datafield><datafield tag="082" ind1="0" ind2="4"><subfield code="a">550</subfield><subfield code="q">DNB</subfield></datafield><datafield tag="100" ind1="0" ind2=" "><subfield code="a">Alan D Chapman</subfield><subfield code="e">verfasserin</subfield><subfield code="4">aut</subfield></datafield><datafield tag="245" ind1="1" ind2="0"><subfield code="a">Constraints on plateau architecture and assembly from deep crustal xenoliths, northern Altiplano (SE Peru)</subfield></datafield><datafield tag="264" ind1=" " ind2="1"><subfield code="c">2015</subfield></datafield><datafield tag="336" ind1=" " ind2=" "><subfield code="a">Text</subfield><subfield code="b">txt</subfield><subfield code="2">rdacontent</subfield></datafield><datafield tag="337" ind1=" " ind2=" "><subfield code="a">ohne Hilfsmittel zu benutzen</subfield><subfield code="b">n</subfield><subfield code="2">rdamedia</subfield></datafield><datafield tag="338" ind1=" " ind2=" "><subfield code="a">Band</subfield><subfield code="b">nc</subfield><subfield code="2">rdacarrier</subfield></datafield><datafield tag="520" ind1=" " ind2=" "><subfield code="a">Newly discovered xenoliths within Pliocene and Quaternary intermediate volcanic rocks from southern Peru permit examination of lithospheric processes by which thick crust (60-70 km) and high average elevations (3-4 km) resulted within the Altiplano, the second most extensive orogenic plateau on Earth. The most common petrographic groups of xenoliths studied here are igneous or meta-igneous rocks with radiogenic isotopic ratios consistent with recent derivation from asthenospheric mantle (...Sr/...Sr = 0.704-0.709, ...Nd/...Nd = 0.5126-0.5129). A second group, consisting of felsic granulite xenoliths exhibiting more radiogenic compositions (...Sr/...Sr = 0.711-0.782, ...Nd/...Nd = 0.5121-0.5126), is interpreted as supracrustal rocks that underwent metamorphism at ~9 kbar (~30-35 km paleodepth, assuming a mean crustal density of 2.8 g/cm...) and ~750 ...C. These rocks are correlated with nonmetamorphosed rocks of the Mitu Group and assigned a Mesozoic (Upper Triassic or younger) age based on detrital zircon U-Pb ages. A felsic granulite Sm-Nd garnet whole-rock isochron of 42 ± 2 Ma demonstrates that garnet growth took place in Eocene time. Monazite grains associated with quenched anatectic melt networks in the same rocks yield ion microprobe U-Pb ages ranging from 3.2 ± 0.2 to 4.4 ± 0.3 Ma (2...). These disparate geochronologic data sets are reconciled by a model wherein Mesozoic cover rocks were transferred to >30 km depth beneath the plateau in the Eocene and progressively heated until at least Pliocene time. Isothermal decompression and partial melting ensued as these rocks were entrained as xenoliths in volcanic host magmas and transported toward the surface. Mafic granulites and peridotites from the same xenolith suite comprise the basement of the metasedimentary sequence, exhibiting isotopic characteristics of Central Andean crust. Calculated equilibrium pressures for these basement rocks are >11 kbar, suggesting that the basement-cover interface lies beneath the northernmost Altiplano at ~30-40 km below the surface. Together, these results indicate that crustal thickening under the northernmost Altiplano started earlier than major latest Oligocene and Miocene uplift episodes affecting the region and was coeval with a flat slab-related regional episode of deformation. Total shortening must have been at least 20% more than previous estimates in order to satisfy the basement to cover depth constraints provided by the xenolith data. Sedimentary rocks at >30 km paleodepth require that Andean basement thrusts decapitated earlier Triassic normal faults, trapping Paleozoic and Mesozoic rocks below the main d...collement. Magma loading from intense Cenozoic plutonism within the plateau probably played an additional role in transporting Mesozoic cover rocks to >30 km and thickening the crust beneath the northern Altiplano. (ProQuest: ... denotes formulae/symbols omitted.)</subfield></datafield><datafield tag="540" ind1=" " ind2=" "><subfield code="a">Nutzungsrecht: © COPYRIGHT 2015 Geological Society of America, Inc.</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Inclusions</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Earth</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Metamorphism (Geology)</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Rocks, Igneous</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Analysis</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Crust</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Lithosphere</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Igneous rock</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Geology</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Magma</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Deformation</subfield></datafield><datafield tag="700" ind1="0" ind2=" "><subfield code="a">Mihai N Ducea</subfield><subfield code="4">oth</subfield></datafield><datafield tag="700" ind1="0" ind2=" "><subfield code="a">Nadine McQuarrie</subfield><subfield code="4">oth</subfield></datafield><datafield tag="700" ind1="0" ind2=" "><subfield code="a">Matthew Coble</subfield><subfield code="4">oth</subfield></datafield><datafield tag="700" ind1="0" ind2=" "><subfield code="a">Lucian Petrescu</subfield><subfield code="4">oth</subfield></datafield><datafield tag="700" ind1="0" ind2=" "><subfield code="a">Derek Hoffman</subfield><subfield code="4">oth</subfield></datafield><datafield tag="773" ind1="0" ind2="8"><subfield code="i">Enthalten in</subfield><subfield code="t">Geological Society of America bulletin</subfield><subfield code="d">Boulder, Colo. [u.a.] : Geological Society of America, 1890</subfield><subfield code="g">127(2015), 11-12, Seite 1777-1797</subfield><subfield code="w">(DE-627)129067199</subfield><subfield code="w">(DE-600)1351-1</subfield><subfield code="w">(DE-576)014398621</subfield><subfield code="x">0016-7606</subfield><subfield code="7">nnns</subfield></datafield><datafield tag="773" ind1="1" ind2="8"><subfield code="g">volume:127</subfield><subfield code="g">year:2015</subfield><subfield code="g">number:11-12</subfield><subfield code="g">pages:1777-1797</subfield></datafield><datafield tag="856" ind1="4" ind2="1"><subfield code="u">http://dx.doi.org/10.1130/B31206.1</subfield><subfield code="3">Volltext</subfield></datafield><datafield tag="856" ind1="4" ind2="2"><subfield code="u">http://search.proquest.com/docview/1729122342</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_USEFLAG_A</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">SYSFLAG_A</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_OLC</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">SSG-OLC-GEO</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">SSG-OPC-GGO</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_ILN_21</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_ILN_22</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_ILN_70</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_ILN_188</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_ILN_2010</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_ILN_2027</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_ILN_4046</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_ILN_4112</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_ILN_4323</subfield></datafield><datafield tag="951" ind1=" " ind2=" "><subfield code="a">AR</subfield></datafield><datafield tag="952" ind1=" " ind2=" "><subfield code="d">127</subfield><subfield code="j">2015</subfield><subfield code="e">11-12</subfield><subfield code="h">1777-1797</subfield></datafield></record></collection>
|
| author |
Alan D Chapman |
| spellingShingle |
Alan D Chapman ddc 550 misc Inclusions misc Earth misc Metamorphism (Geology) misc Rocks, Igneous misc Analysis misc Crust misc Lithosphere misc Igneous rock misc Geology misc Magma misc Deformation Constraints on plateau architecture and assembly from deep crustal xenoliths, northern Altiplano (SE Peru) |
| authorStr |
Alan D Chapman |
| ppnlink_with_tag_str_mv |
@@773@@(DE-627)129067199 |
| format |
Article |
| dewey-ones |
550 - Earth sciences |
| delete_txt_mv |
keep |
| author_role |
aut |
| collection |
OLC |
| remote_str |
false |
| illustrated |
Not Illustrated |
| issn |
0016-7606 |
| topic_title |
550 DNB Constraints on plateau architecture and assembly from deep crustal xenoliths, northern Altiplano (SE Peru) Inclusions Earth Metamorphism (Geology) Rocks, Igneous Analysis Crust Lithosphere Igneous rock Geology Magma Deformation |
| topic |
ddc 550 misc Inclusions misc Earth misc Metamorphism (Geology) misc Rocks, Igneous misc Analysis misc Crust misc Lithosphere misc Igneous rock misc Geology misc Magma misc Deformation |
| topic_unstemmed |
ddc 550 misc Inclusions misc Earth misc Metamorphism (Geology) misc Rocks, Igneous misc Analysis misc Crust misc Lithosphere misc Igneous rock misc Geology misc Magma misc Deformation |
| topic_browse |
ddc 550 misc Inclusions misc Earth misc Metamorphism (Geology) misc Rocks, Igneous misc Analysis misc Crust misc Lithosphere misc Igneous rock misc Geology misc Magma misc Deformation |
| format_facet |
Aufsätze Gedruckte Aufsätze |
| format_main_str_mv |
Text Zeitschrift/Artikel |
| carriertype_str_mv |
nc |
| author2_variant |
m n d mnd n m nm m c mc l p lp d h dh |
| hierarchy_parent_title |
Geological Society of America bulletin |
| hierarchy_parent_id |
129067199 |
| dewey-tens |
550 - Earth sciences & geology |
| hierarchy_top_title |
Geological Society of America bulletin |
| isfreeaccess_txt |
false |
| familylinks_str_mv |
(DE-627)129067199 (DE-600)1351-1 (DE-576)014398621 |
| title |
Constraints on plateau architecture and assembly from deep crustal xenoliths, northern Altiplano (SE Peru) |
| ctrlnum |
(DE-627)OLC1968145478 (DE-599)GBVOLC1968145478 (PRQ)c1670-28682ef8dcc5db5634300e66a5e1da5e0c00fdd17de39992c96f89d3c3cdec270 (KEY)0093391020150000127001101777constraintsonplateauarchitectureandassemblyfromdee |
| title_full |
Constraints on plateau architecture and assembly from deep crustal xenoliths, northern Altiplano (SE Peru) |
| author_sort |
Alan D Chapman |
| journal |
Geological Society of America bulletin |
| journalStr |
Geological Society of America bulletin |
| lang_code |
eng |
| isOA_bool |
false |
| dewey-hundreds |
500 - Science |
| recordtype |
marc |
| publishDateSort |
2015 |
| contenttype_str_mv |
txt |
| container_start_page |
1777 |
| author_browse |
Alan D Chapman |
| container_volume |
127 |
| class |
550 DNB |
| format_se |
Aufsätze |
| author-letter |
Alan D Chapman |
| doi_str_mv |
10.1130/B31206.1 |
| dewey-full |
550 |
| title_sort |
constraints on plateau architecture and assembly from deep crustal xenoliths, northern altiplano (se peru) |
| title_auth |
Constraints on plateau architecture and assembly from deep crustal xenoliths, northern Altiplano (SE Peru) |
| abstract |
Newly discovered xenoliths within Pliocene and Quaternary intermediate volcanic rocks from southern Peru permit examination of lithospheric processes by which thick crust (60-70 km) and high average elevations (3-4 km) resulted within the Altiplano, the second most extensive orogenic plateau on Earth. The most common petrographic groups of xenoliths studied here are igneous or meta-igneous rocks with radiogenic isotopic ratios consistent with recent derivation from asthenospheric mantle (...Sr/...Sr = 0.704-0.709, ...Nd/...Nd = 0.5126-0.5129). A second group, consisting of felsic granulite xenoliths exhibiting more radiogenic compositions (...Sr/...Sr = 0.711-0.782, ...Nd/...Nd = 0.5121-0.5126), is interpreted as supracrustal rocks that underwent metamorphism at ~9 kbar (~30-35 km paleodepth, assuming a mean crustal density of 2.8 g/cm...) and ~750 ...C. These rocks are correlated with nonmetamorphosed rocks of the Mitu Group and assigned a Mesozoic (Upper Triassic or younger) age based on detrital zircon U-Pb ages. A felsic granulite Sm-Nd garnet whole-rock isochron of 42 ± 2 Ma demonstrates that garnet growth took place in Eocene time. Monazite grains associated with quenched anatectic melt networks in the same rocks yield ion microprobe U-Pb ages ranging from 3.2 ± 0.2 to 4.4 ± 0.3 Ma (2...). These disparate geochronologic data sets are reconciled by a model wherein Mesozoic cover rocks were transferred to >30 km depth beneath the plateau in the Eocene and progressively heated until at least Pliocene time. Isothermal decompression and partial melting ensued as these rocks were entrained as xenoliths in volcanic host magmas and transported toward the surface. Mafic granulites and peridotites from the same xenolith suite comprise the basement of the metasedimentary sequence, exhibiting isotopic characteristics of Central Andean crust. Calculated equilibrium pressures for these basement rocks are >11 kbar, suggesting that the basement-cover interface lies beneath the northernmost Altiplano at ~30-40 km below the surface. Together, these results indicate that crustal thickening under the northernmost Altiplano started earlier than major latest Oligocene and Miocene uplift episodes affecting the region and was coeval with a flat slab-related regional episode of deformation. Total shortening must have been at least 20% more than previous estimates in order to satisfy the basement to cover depth constraints provided by the xenolith data. Sedimentary rocks at >30 km paleodepth require that Andean basement thrusts decapitated earlier Triassic normal faults, trapping Paleozoic and Mesozoic rocks below the main d...collement. Magma loading from intense Cenozoic plutonism within the plateau probably played an additional role in transporting Mesozoic cover rocks to >30 km and thickening the crust beneath the northern Altiplano. (ProQuest: ... denotes formulae/symbols omitted.) |
| abstractGer |
Newly discovered xenoliths within Pliocene and Quaternary intermediate volcanic rocks from southern Peru permit examination of lithospheric processes by which thick crust (60-70 km) and high average elevations (3-4 km) resulted within the Altiplano, the second most extensive orogenic plateau on Earth. The most common petrographic groups of xenoliths studied here are igneous or meta-igneous rocks with radiogenic isotopic ratios consistent with recent derivation from asthenospheric mantle (...Sr/...Sr = 0.704-0.709, ...Nd/...Nd = 0.5126-0.5129). A second group, consisting of felsic granulite xenoliths exhibiting more radiogenic compositions (...Sr/...Sr = 0.711-0.782, ...Nd/...Nd = 0.5121-0.5126), is interpreted as supracrustal rocks that underwent metamorphism at ~9 kbar (~30-35 km paleodepth, assuming a mean crustal density of 2.8 g/cm...) and ~750 ...C. These rocks are correlated with nonmetamorphosed rocks of the Mitu Group and assigned a Mesozoic (Upper Triassic or younger) age based on detrital zircon U-Pb ages. A felsic granulite Sm-Nd garnet whole-rock isochron of 42 ± 2 Ma demonstrates that garnet growth took place in Eocene time. Monazite grains associated with quenched anatectic melt networks in the same rocks yield ion microprobe U-Pb ages ranging from 3.2 ± 0.2 to 4.4 ± 0.3 Ma (2...). These disparate geochronologic data sets are reconciled by a model wherein Mesozoic cover rocks were transferred to >30 km depth beneath the plateau in the Eocene and progressively heated until at least Pliocene time. Isothermal decompression and partial melting ensued as these rocks were entrained as xenoliths in volcanic host magmas and transported toward the surface. Mafic granulites and peridotites from the same xenolith suite comprise the basement of the metasedimentary sequence, exhibiting isotopic characteristics of Central Andean crust. Calculated equilibrium pressures for these basement rocks are >11 kbar, suggesting that the basement-cover interface lies beneath the northernmost Altiplano at ~30-40 km below the surface. Together, these results indicate that crustal thickening under the northernmost Altiplano started earlier than major latest Oligocene and Miocene uplift episodes affecting the region and was coeval with a flat slab-related regional episode of deformation. Total shortening must have been at least 20% more than previous estimates in order to satisfy the basement to cover depth constraints provided by the xenolith data. Sedimentary rocks at >30 km paleodepth require that Andean basement thrusts decapitated earlier Triassic normal faults, trapping Paleozoic and Mesozoic rocks below the main d...collement. Magma loading from intense Cenozoic plutonism within the plateau probably played an additional role in transporting Mesozoic cover rocks to >30 km and thickening the crust beneath the northern Altiplano. (ProQuest: ... denotes formulae/symbols omitted.) |
| abstract_unstemmed |
Newly discovered xenoliths within Pliocene and Quaternary intermediate volcanic rocks from southern Peru permit examination of lithospheric processes by which thick crust (60-70 km) and high average elevations (3-4 km) resulted within the Altiplano, the second most extensive orogenic plateau on Earth. The most common petrographic groups of xenoliths studied here are igneous or meta-igneous rocks with radiogenic isotopic ratios consistent with recent derivation from asthenospheric mantle (...Sr/...Sr = 0.704-0.709, ...Nd/...Nd = 0.5126-0.5129). A second group, consisting of felsic granulite xenoliths exhibiting more radiogenic compositions (...Sr/...Sr = 0.711-0.782, ...Nd/...Nd = 0.5121-0.5126), is interpreted as supracrustal rocks that underwent metamorphism at ~9 kbar (~30-35 km paleodepth, assuming a mean crustal density of 2.8 g/cm...) and ~750 ...C. These rocks are correlated with nonmetamorphosed rocks of the Mitu Group and assigned a Mesozoic (Upper Triassic or younger) age based on detrital zircon U-Pb ages. A felsic granulite Sm-Nd garnet whole-rock isochron of 42 ± 2 Ma demonstrates that garnet growth took place in Eocene time. Monazite grains associated with quenched anatectic melt networks in the same rocks yield ion microprobe U-Pb ages ranging from 3.2 ± 0.2 to 4.4 ± 0.3 Ma (2...). These disparate geochronologic data sets are reconciled by a model wherein Mesozoic cover rocks were transferred to >30 km depth beneath the plateau in the Eocene and progressively heated until at least Pliocene time. Isothermal decompression and partial melting ensued as these rocks were entrained as xenoliths in volcanic host magmas and transported toward the surface. Mafic granulites and peridotites from the same xenolith suite comprise the basement of the metasedimentary sequence, exhibiting isotopic characteristics of Central Andean crust. Calculated equilibrium pressures for these basement rocks are >11 kbar, suggesting that the basement-cover interface lies beneath the northernmost Altiplano at ~30-40 km below the surface. Together, these results indicate that crustal thickening under the northernmost Altiplano started earlier than major latest Oligocene and Miocene uplift episodes affecting the region and was coeval with a flat slab-related regional episode of deformation. Total shortening must have been at least 20% more than previous estimates in order to satisfy the basement to cover depth constraints provided by the xenolith data. Sedimentary rocks at >30 km paleodepth require that Andean basement thrusts decapitated earlier Triassic normal faults, trapping Paleozoic and Mesozoic rocks below the main d...collement. Magma loading from intense Cenozoic plutonism within the plateau probably played an additional role in transporting Mesozoic cover rocks to >30 km and thickening the crust beneath the northern Altiplano. (ProQuest: ... denotes formulae/symbols omitted.) |
| collection_details |
GBV_USEFLAG_A SYSFLAG_A GBV_OLC SSG-OLC-GEO SSG-OPC-GGO GBV_ILN_21 GBV_ILN_22 GBV_ILN_70 GBV_ILN_188 GBV_ILN_2010 GBV_ILN_2027 GBV_ILN_4046 GBV_ILN_4112 GBV_ILN_4323 |
| container_issue |
11-12 |
| title_short |
Constraints on plateau architecture and assembly from deep crustal xenoliths, northern Altiplano (SE Peru) |
| url |
http://dx.doi.org/10.1130/B31206.1 http://search.proquest.com/docview/1729122342 |
| remote_bool |
false |
| author2 |
Mihai N Ducea Nadine McQuarrie Matthew Coble Lucian Petrescu Derek Hoffman |
| author2Str |
Mihai N Ducea Nadine McQuarrie Matthew Coble Lucian Petrescu Derek Hoffman |
| ppnlink |
129067199 |
| mediatype_str_mv |
n |
| isOA_txt |
false |
| hochschulschrift_bool |
false |
| author2_role |
oth oth oth oth oth |
| doi_str |
10.1130/B31206.1 |
| up_date |
2024-07-04T02:43:42.997Z |
| _version_ |
1803614707256393729 |
| fullrecord_marcxml |
<?xml version="1.0" encoding="UTF-8"?><collection xmlns="http://www.loc.gov/MARC21/slim"><record><leader>01000caa a2200265 4500</leader><controlfield tag="001">OLC1968145478</controlfield><controlfield tag="003">DE-627</controlfield><controlfield tag="005">20220217014102.0</controlfield><controlfield tag="007">tu</controlfield><controlfield tag="008">160206s2015 xx ||||| 00| ||eng c</controlfield><datafield tag="024" ind1="7" ind2=" "><subfield code="a">10.1130/B31206.1</subfield><subfield code="2">doi</subfield></datafield><datafield tag="028" ind1="5" ind2="2"><subfield code="a">PQ20160617</subfield></datafield><datafield tag="035" ind1=" " ind2=" "><subfield code="a">(DE-627)OLC1968145478</subfield></datafield><datafield tag="035" ind1=" " ind2=" "><subfield code="a">(DE-599)GBVOLC1968145478</subfield></datafield><datafield tag="035" ind1=" " ind2=" "><subfield code="a">(PRQ)c1670-28682ef8dcc5db5634300e66a5e1da5e0c00fdd17de39992c96f89d3c3cdec270</subfield></datafield><datafield tag="035" ind1=" " ind2=" "><subfield code="a">(KEY)0093391020150000127001101777constraintsonplateauarchitectureandassemblyfromdee</subfield></datafield><datafield tag="040" ind1=" " ind2=" "><subfield code="a">DE-627</subfield><subfield code="b">ger</subfield><subfield code="c">DE-627</subfield><subfield code="e">rakwb</subfield></datafield><datafield tag="041" ind1=" " ind2=" "><subfield code="a">eng</subfield></datafield><datafield tag="082" ind1="0" ind2="4"><subfield code="a">550</subfield><subfield code="q">DNB</subfield></datafield><datafield tag="100" ind1="0" ind2=" "><subfield code="a">Alan D Chapman</subfield><subfield code="e">verfasserin</subfield><subfield code="4">aut</subfield></datafield><datafield tag="245" ind1="1" ind2="0"><subfield code="a">Constraints on plateau architecture and assembly from deep crustal xenoliths, northern Altiplano (SE Peru)</subfield></datafield><datafield tag="264" ind1=" " ind2="1"><subfield code="c">2015</subfield></datafield><datafield tag="336" ind1=" " ind2=" "><subfield code="a">Text</subfield><subfield code="b">txt</subfield><subfield code="2">rdacontent</subfield></datafield><datafield tag="337" ind1=" " ind2=" "><subfield code="a">ohne Hilfsmittel zu benutzen</subfield><subfield code="b">n</subfield><subfield code="2">rdamedia</subfield></datafield><datafield tag="338" ind1=" " ind2=" "><subfield code="a">Band</subfield><subfield code="b">nc</subfield><subfield code="2">rdacarrier</subfield></datafield><datafield tag="520" ind1=" " ind2=" "><subfield code="a">Newly discovered xenoliths within Pliocene and Quaternary intermediate volcanic rocks from southern Peru permit examination of lithospheric processes by which thick crust (60-70 km) and high average elevations (3-4 km) resulted within the Altiplano, the second most extensive orogenic plateau on Earth. The most common petrographic groups of xenoliths studied here are igneous or meta-igneous rocks with radiogenic isotopic ratios consistent with recent derivation from asthenospheric mantle (...Sr/...Sr = 0.704-0.709, ...Nd/...Nd = 0.5126-0.5129). A second group, consisting of felsic granulite xenoliths exhibiting more radiogenic compositions (...Sr/...Sr = 0.711-0.782, ...Nd/...Nd = 0.5121-0.5126), is interpreted as supracrustal rocks that underwent metamorphism at ~9 kbar (~30-35 km paleodepth, assuming a mean crustal density of 2.8 g/cm...) and ~750 ...C. These rocks are correlated with nonmetamorphosed rocks of the Mitu Group and assigned a Mesozoic (Upper Triassic or younger) age based on detrital zircon U-Pb ages. A felsic granulite Sm-Nd garnet whole-rock isochron of 42 ± 2 Ma demonstrates that garnet growth took place in Eocene time. Monazite grains associated with quenched anatectic melt networks in the same rocks yield ion microprobe U-Pb ages ranging from 3.2 ± 0.2 to 4.4 ± 0.3 Ma (2...). These disparate geochronologic data sets are reconciled by a model wherein Mesozoic cover rocks were transferred to >30 km depth beneath the plateau in the Eocene and progressively heated until at least Pliocene time. Isothermal decompression and partial melting ensued as these rocks were entrained as xenoliths in volcanic host magmas and transported toward the surface. Mafic granulites and peridotites from the same xenolith suite comprise the basement of the metasedimentary sequence, exhibiting isotopic characteristics of Central Andean crust. Calculated equilibrium pressures for these basement rocks are >11 kbar, suggesting that the basement-cover interface lies beneath the northernmost Altiplano at ~30-40 km below the surface. Together, these results indicate that crustal thickening under the northernmost Altiplano started earlier than major latest Oligocene and Miocene uplift episodes affecting the region and was coeval with a flat slab-related regional episode of deformation. Total shortening must have been at least 20% more than previous estimates in order to satisfy the basement to cover depth constraints provided by the xenolith data. Sedimentary rocks at >30 km paleodepth require that Andean basement thrusts decapitated earlier Triassic normal faults, trapping Paleozoic and Mesozoic rocks below the main d...collement. Magma loading from intense Cenozoic plutonism within the plateau probably played an additional role in transporting Mesozoic cover rocks to >30 km and thickening the crust beneath the northern Altiplano. (ProQuest: ... denotes formulae/symbols omitted.)</subfield></datafield><datafield tag="540" ind1=" " ind2=" "><subfield code="a">Nutzungsrecht: © COPYRIGHT 2015 Geological Society of America, Inc.</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Inclusions</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Earth</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Metamorphism (Geology)</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Rocks, Igneous</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Analysis</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Crust</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Lithosphere</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Igneous rock</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Geology</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Magma</subfield></datafield><datafield tag="650" ind1=" " ind2="4"><subfield code="a">Deformation</subfield></datafield><datafield tag="700" ind1="0" ind2=" "><subfield code="a">Mihai N Ducea</subfield><subfield code="4">oth</subfield></datafield><datafield tag="700" ind1="0" ind2=" "><subfield code="a">Nadine McQuarrie</subfield><subfield code="4">oth</subfield></datafield><datafield tag="700" ind1="0" ind2=" "><subfield code="a">Matthew Coble</subfield><subfield code="4">oth</subfield></datafield><datafield tag="700" ind1="0" ind2=" "><subfield code="a">Lucian Petrescu</subfield><subfield code="4">oth</subfield></datafield><datafield tag="700" ind1="0" ind2=" "><subfield code="a">Derek Hoffman</subfield><subfield code="4">oth</subfield></datafield><datafield tag="773" ind1="0" ind2="8"><subfield code="i">Enthalten in</subfield><subfield code="t">Geological Society of America bulletin</subfield><subfield code="d">Boulder, Colo. [u.a.] : Geological Society of America, 1890</subfield><subfield code="g">127(2015), 11-12, Seite 1777-1797</subfield><subfield code="w">(DE-627)129067199</subfield><subfield code="w">(DE-600)1351-1</subfield><subfield code="w">(DE-576)014398621</subfield><subfield code="x">0016-7606</subfield><subfield code="7">nnns</subfield></datafield><datafield tag="773" ind1="1" ind2="8"><subfield code="g">volume:127</subfield><subfield code="g">year:2015</subfield><subfield code="g">number:11-12</subfield><subfield code="g">pages:1777-1797</subfield></datafield><datafield tag="856" ind1="4" ind2="1"><subfield code="u">http://dx.doi.org/10.1130/B31206.1</subfield><subfield code="3">Volltext</subfield></datafield><datafield tag="856" ind1="4" ind2="2"><subfield code="u">http://search.proquest.com/docview/1729122342</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_USEFLAG_A</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">SYSFLAG_A</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_OLC</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">SSG-OLC-GEO</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">SSG-OPC-GGO</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_ILN_21</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_ILN_22</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_ILN_70</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_ILN_188</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_ILN_2010</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_ILN_2027</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_ILN_4046</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_ILN_4112</subfield></datafield><datafield tag="912" ind1=" " ind2=" "><subfield code="a">GBV_ILN_4323</subfield></datafield><datafield tag="951" ind1=" " ind2=" "><subfield code="a">AR</subfield></datafield><datafield tag="952" ind1=" " ind2=" "><subfield code="d">127</subfield><subfield code="j">2015</subfield><subfield code="e">11-12</subfield><subfield code="h">1777-1797</subfield></datafield></record></collection>
|
| score |
7.4005537 |