Chemical and isotopic constraints on the origin of low-silica latite and andesite from the Andes of central Peru

Noble, Donald C.; Bowman, H.; Hebert, Alvin J.; Silberman, Miles L.; Heropoulos, Chris; Fabbi, B. P.; Hedge, Carl E.

doi:10.1130/0091-7613(1975)3<501:caicot>2.0.co;2

Cited by 44 publications

(15 citation statements)

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“…It is also suggested that the 87Sr/86Sr ratios of source magmas are regionally different. The lowest 87Sr/86Sr ratio (0 .7049) in a basaltic rock in the B-C region is higher than the exceptionally low ratios (0.7041-0.7042) reported for samples in the Central Andes arc (NOBLE et al, 1975;THORPE and FRANCIS, 1979). This may be due to the heterogeneity in the 87Sr/86Sr ratio of the source material beneath the Central Andes arc.…”

Section: Samplescontrasting

confidence: 42%

“…In addition to these data, exceptionally low ratios were reported for 3 rock samples. Those are a low-Si latite (0.7042) and a low-Si andesite (0.7042) in central Peru, the northernmost region of the Central Andes arc (NOBLE et al, 1975), and an alkali basalt (0.7041) in Bolivia . The 87Sr/86Sr ratios for rocks in southern Peru obtained in this work overlap the normal range of the ratios (above 0.705 1) for those of the Central Andes arc, except for one sample (No.…”

Section: Samplesmentioning

confidence: 99%

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Regional variation of 87Sr/86Sr ratio in late Cenozoic volcanic rocks from southern Peru.

Notsu

Lajo

1984

Geochem. J.

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We determined the 87Sr/S6Sr ratios of 53 late Cenozoic volcanic rocks collected in an area of 700km X 300km in southern Peru along the Central Andes volcanic arc. The measured B7Sr/86Sr ratios scatter largely, ranging from 0.7049 to 0.7082. The ratios roughly correlate with Si02 contents, suggesting that the source magma is contaminated by crustal materials during fractional crystallization process. The lowest value is obtained in a basaltic rock.Regional variation in 87Sr/86Sr ratios is observed. In the along-arc direction from northwest to south east, the ratios increase, reach the maximum value near Arequipa City and then decrease in accordance with the change of.descending mode of the Nazca plate. The maximum 87Sr/86Sr ratio is observed in the region where the simple subduction of the Nazca plate is being distorted.

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Section: Samplescontrasting

confidence: 42%

Section: Samplesmentioning

confidence: 99%

Regional variation of 87Sr/86Sr ratio in late Cenozoic volcanic rocks from southern Peru.

Notsu

Lajo

1984

Geochem. J.

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“…the linearitv of the data suggest -Cr and Ni contents The Cr and Ni contents of the sanukitoids (averaging 350 and 150 ppm, respectively) are similar to those of young volcanic rocks suspected of having a mantle origin. For example, high-Mg andesites from the Setouchi volcanic belt average 450 ppm Cr and 200 ppm Ni (Table 2), and a high-Mg basaltic andesite from Peru has 395 ppm Cr and 139 ppm Ni (Noble et al 1975). If the Archean sanukitoids fractionated even a small amount of olivine, then Ni contents would have been higher in the primary melts.…”

Section: Mgo -Feo Systematicsmentioning

confidence: 97%

Petrogenesis of mantle-derived, LILE-enriched Archean monzodiorites and trachyandesites (sanukitoids) in southwestern Superior Province

Stern¹,

Hanson²,

Shirey³

1989

Can. J. Earth Sci.

217

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In southwestern Superior Province, diorite, monzodiorite, and trachyandesite ("sanukitoids") occurring within syn-to post-tectonic intrusive complexes and within greenstone belts have the following chemical characteristics: 55-60 wt. % SO2, MgO > 6 wt. %, Mg# > 0.60, Ni and Cr both > 100 ppm, Na20 + K20 = 6 wt. %, Sr and Ba both 600-1800 ppm, and rare-earth-element (REE) patterns that are strongly light rare-earth-element (LREE) enriched (Ce, = 80-250, Yb, = 4-10) and show no Eu anomalies. Sanukitoids and their granodioritic derivatives constitute at least 5 % of the exposed crust in the study area. The sanukitoids cannot be derived by melting, fractionation, or crustal contamination of basalts or lamprophyres that are coeval with the sanukitoids. Crustal contamination of komatiites fails to explain the high large-ion-lithophile-element (LILE) contents of the sanukitoids. Rather, we suggest that the sanukitoids were derived by hydrous melting of LILE-enriched mantle peridotite at pressures between 10 and 15 kbar. The sanukitoids with steepest REE patterns have the lowest FeO contents, indicating that the part of the mantle source with the highest Mg# had the most fractionated REE pattern prior to melting. Mantle source regions to the sanukitoids had different Mg#'s and were enriched in LILE'S (metasomatized) to varying extents by fluids of crustal or mantle origin prior to melting.Dans le sud-ouest de la province du lac SupCrieur, la diorite, la monzonite et la trachyandesite (<< sanukitoides *) qui affleurent dans les complexes intrusifs syn-et post-tectoniques, ainsi que dans les ceintures de roches vertes, prksentent les caractCristiques chimiques suivants : 55 -60% par poids de SO2, MgO > 6 % par poids, valeurs Mg# > 0,60 Ni et Cr > 100 pprn chacun, Na20 + K 2 0 = 6 % par poids, Sr et Ba 600-1800 pprn chacun et les courbes des terres rares fortement enrichies en terres rares ltgkes (Ce, = 80-250, Yb, = 4-10) et sans anomalies apparentes en Eu. Les sanukitoides et leurs dCrivCs granodioritiques foment au moins 5 % de la crotite exposee dans la rtgion CtudiCe. Les sanukitoides ne peuvent pas originer de la fusion, du fractionnement ou de la contamination crustale des basaltes ou des lamprophyres contemporains des sanukitoides. La contamination crustale des komatiites est insuffisante pour expliquer les teneurs en ClCments lithophiles B grand rayon fonique (LILE) dans les sanukitoides. Nous suggkrons plut6t que les sanukitoides dkrivaient de la fusion hydratke d'une pkrioditite du manteau enrichie en ClCments lithophiles B grand rayon ionique, B des pressions entre 10 et 15 kbar.Les sanukitoides qui prksentent les courbes les plus abruptes de distribution des terres rares renferment plus les faibles teneurs en FeO, attestant que la portion du magma parent dans le manteau ayant les valeurs Mg# les plus fortes corresponait au stade de fractionnement maximum des terres rares prkc6dant la fusion. Les rBgions du manteau d'oh dCrivent les sanukitoides possB daient des valeurs Mg# diffkrentes et furent enrichies en ClC...

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“…In general, high Ba and Sr contents (>1 000 ppm) appear to be more commonly associated with continental rather than oceanic calc-alkaline magma suites (e.g. Noble et al 1975) although alkaline magmas are quite commonly Ba and Sr rich. Halliday and Stephens (1984) concluded that this was a mantle-derived characteristic but noted that a similar but much less pronounced feature characterised the c. 2-9 Ga Lewisian Complex, suggesting a regional feature and the existence of an ancient lithospheric chemical province.…”

Section: The Late Caledonian Granites-gross Chemical Featuresmentioning

confidence: 97%

Isotopic and chemical constraints on the building of the deep Scottish lithosphere

Halliday

Stephens

Hunter

et al. 1985

SJG

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SYNOPSISThe Scottish late Caledonian granites define a chemical province characterised by high Na, Ba and Sr abundances, particularly towards the north and west where they also have higher Zn, REEs and La/Y and lower Rb and Th. A comparison with data for inclusions found in younger volcanics and hypabyssal intrusions and thought to have been excavated from the mantle and lower crust indicates that the source of at least some of the chemical variation in the granitic magmas lies in the lithospheric mantle. The asthenosphere or postulated subducted slab material from the Iapetus ocean floor cannot have direcdy contributed significant amounts of these elements to most of the granitoids. Further, isotopic data clearly indicate that lower crust-derived materials are essential components of the more evolved granites, implying that considerable melting took place near the Moho.The age of the lower crust parallels the changes in chemistry in the lithospheric mantle which suggests that the Moho is not a major tectonic discontinuity. The Mid-Grampian line probably represents the rifted continental edge during Dalradian deposition. There is no isotopic evidence for primary crust of Grenville age under Scotland; rather the lower crust appears to be a complicated mixture including some components which are very young (probably Lower Palaeozoic) under the Midland Valley. The only location where clearly enriched mantle has been identified is under the Lewisian of the Outer Hebrides. The lower crust in this region is also Lewisian, apparently metasomatised. We tentatively suggest that the chemical enrichments and depletions in the lithosphere north of the Mid Grampian line are most simply explained by a volatile flushing mechanism. GRANITES AND THEIR SOURCE REGIONSThe Mesozoic-Tertiary circum-Pacific Cordilleran batholiths contain both mantle-derived and crust-derived components (Hurley et al. 1965;Taylor and Silver 1978; DePaolo 1981). As such their generation appears to be both a major crust-forming process and a mechanism for rapid redistribution and recycling of crustal materials. T h e Caledonian granites of the world cannot be easily related to Scott.

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Chemical and isotopic constraints on the origin of low-silica latite and andesite from the Andes of central Peru

Cited by 44 publications

References 0 publications

Regional variation of 87Sr/86Sr ratio in late Cenozoic volcanic rocks from southern Peru.

Regional variation of 87Sr/86Sr ratio in late Cenozoic volcanic rocks from southern Peru.

Petrogenesis of mantle-derived, LILE-enriched Archean monzodiorites and trachyandesites (sanukitoids) in southwestern Superior Province

Isotopic and chemical constraints on the building of the deep Scottish lithosphere

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