Abstract
Major and trace element concentrations and initial 87Sr/86Sr ratios of lavas from the Aleutian volcanic centers of Adak and Atka have been used to study the evolution of their respective lithospheric plumbing systems. The centers are within 150 km of one another and show similar overall silica ranges (47–67%), but Adak (∼40 km3) is smaller than Atka (∼200 km3). Adak's lavas are chemically and isotopically heterogeneous (87Sr/86Sr:0.70285–0.70330) and two units contain lithospheric xenoliths. The lavas of the much larger Atka, on the other hand, have much less variability in major and trace elements as well as 87Sr/86Sr (0.70320–0.70345). We suggest that these characteristics are a measure of the relative maturity and “cleanliness” of the lithospheric plumbing systems that supply magma to these centers. Because Aleutian volcanic centers often remain fixed for relatively long periods of time (∼5 m.y.), once established, magmatic passageways are repeatedly used. Young plumbing systems are relatively cool and contain large amounts of wallrock contaminant, and ascending magmas undergo contamination as well as concurrent crystallization and fractionation. With time, however, heat and mass transfer between ascending magmas and wallrock produce thermal and chemical boundary layers that insulate subsequent magmas. In effect, the plumbing system matures. The chemical heterogeneity displayed by young, “dirty” systems (like Adak) reflects not only the magma source but also the wallrock encountered during ascent and possibly the effects of extensive crystal fractionation. Thus, it is the petrologic data of mature, clean systems, like Atka, that yield the most direct and unambiguous information on the ultimate origin of the lavas and their near surface evolution.
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Arculus RJ, DeLong SE, Kay RW, Sun SS (1977) The alkalic rock suite of Bogoslof Island, Eastern Aleutian arc, Alaska. J Geol 85:177–186
Baker DR, Eggler DH (1983) Fractionation paths of Atka (Aleutians) high-alumina basalts: constraints from phase relations. J Volcanol Geotherm Res 18:387–404
Coats RR (1952) Magmatic differentiation in Tertiary and Quaternary volcanic rocks from Adak and Kanaga Islands, Aleutian Islands, Alaska. Geol Soc Am Bull 63:485–514
Coats RR (1956) Geology of northern Adak, Alaska. US Geol Surv Bull 1028-C:47–67
Conrad WK, Kay RW (1984) Ultramafic and mafic inclusions from Adak Island: crystallization history, and implications for the nature of primary magmas and crustal evolution in the Aleutian arc. J Petrol 25:80–125
Conrad WK, Kay SM, Kay RW (1983) Magma mixing in the Aleutian arc: evidence from cognate inclusions and composite xenoliths. J Volcanol Geotherm Res 18:279–295
Debari SM, Kay SM, Kay RW (1984) Ultramafic xenoliths from Adagdak Volcano, Adak Island, Alaska: igneous cumulates from the lowermost crust and upper mantle of an island arc (abs). EOS 65:1136
DeLong SE, Hodges FN, Arculus RJ (1975) Ultramafic and mafic inclusions, Kanaga Island, Alaska and the occurence of alkaline rocks in island arcs. J Geol 83:721–736
DeLong SE, Perfit MR, McCulloch MT, Ach J (1984) Magmatic evolution of Semisopochnoi Island, Alaska: trace-element and isotopic constraints. J Geol (submitted)
DePaolo DJ (1981) Trace element and isotopic effects of combined wallrock assimilation and fractional crystallization. Earth Planet Sci Lett 53:189–202
Fraser GD, Barnett HF (1959) Geology of Delarof and Andreanof Islands, Alaska. US Geol Surv Bull 1028-I:211–248
Frey FA, Clague DA (1983) Geochemistry of diverse basalt types from Loihi Seamont, Hawaii: petrogenetic implications. Earth Planet Sci Lett 66:337–355
Grow JA (1973) Crustal and upper mantle structure of the central Aleutian arc. Geol Soc Am Bull 84:2169–2192
Helmberger DV (1977) Fine structure of an Aleutian crustal section. Geophys J R Astron Soc 48:81–90
Kay RW (1977) Geochemical constraints on the origin of Aleutian magmas. In: Talwani M, Pittman III, WC (eds) Island Arcs, Deep Sea Trenches and Back Arc Basins. Am Geophys Union, pp 229–242
Kay RW (1978) Aleutian magnesium andesites: melts from subducted Pacific Ocean crust. J Volcanol Geotherm Res 4:117–132
Kay RW, Sun SS, Lee-Hu C-N (1978) Pb and Sr isotopes in volcanic rocks from the Aleutian Islands and Pribilof Islands, Alaska. Geochim Cosmochim Acta 42:263–273
Kay SM, Kay RW, Citron GP (1982) Tectonic controls on tholeiitic and calc-alkaline magmatism in the Aleutian arc. J Geophys Res 87:4051–4072
Marsh BD (1976) Some Aleutian andesites: their nature and source. J Geol 84:27–45
Marsh BD (1978) On the cooling of ascending andesitic magma. Philos Trans R Soc London A288:11–625
Marsh BD (1980) Geology and petrology of northern Atka, Aleutian Islands, Alaska (abs). Geol Soc Am Abstr with Progr 12:476
Marsh BD (1982a) On the mechanics of igneous diapirism, stoping, and zone melting. Am J Sci 282:800–855
Marsh BD (1982b) The Aleutians. In: Thorpe RS (ed) Andesites and Related Rocks, Wiley, pp 99–114
Marsh BD (1984) Mechanics and energetics of magma formation and ascension. In: Boyd FR Jr (ed) Explosive volcanism: inception, evolution, and hazards. National Academy Press, Washington DC, pp 67–83
McCulloch MT, Perfit MR (1981) 143Nd/144Nd, 87Sr/86Sr and trace element constraints on the petrogenesis of Aleutian island arc magmas. Earth Planet Sci Lett 56:167–179
Mengel K, Kram U, Wedepohl KH, Gohen E (1984) Sr isotopes in peridotite xenoliths and their basaltic host rocks from the northern Hessian Depression (NW Germany). Contrib Mineral Petrol 87:369–375
Morris JD, Hart SR (1983) Isotopic and incompatible element constraints on the genesis of island arc volcanics from Cold Bay and Amak Island, Aleutians, and implications for mantle structure. Geochim Cosmochim Acta 47:2015–2030
Myers JD, Sinha AK (1984) A detailed Pb isotopic study of crustal contamination/assimilation: the Edgecumbe volcanic field, SE Alaska. Geochim Cosmochim Acta 49:1343–1355
Myers JD, Sinha AK, Marsh BD (1984) Assimilation of crustal material by basaltic magma: strontium isotopic and trace element data from the Edgecumbe volcanic field, SE Alaska. J Petrol 25:1–26
Myers JD, Marsh BD, Sinha AK (1985) Geochemical and strontium isotopic characteristics of parental Aleutian arc magmas: evidence from the basaltic lavas of Atka. Contrib Mineral Pet rol (in press)
Mysen BO, Kushiro I (1977) Compositional variations of coexisting phases with degree of melting of peridotite in the upper mantle. Am Mineral 62:843–865
Norrish K, Chappell BW (1977) X-ray fluorescence spectrometry. In: Zussman J (ed) Physical Methods in Determinative Mineralogy, Academic Press, New York, pp 201–272
Perfit MR, Gust DA, Bence AE, Arculus RJ, Taylor SR (1980a) Chemical characteristics of island-arc basalts: implications for mantle sources. Chem Geol 30:227–256
Perfit MR, Brueckner H, Lawrence JR, Kay RW (1980b) Trace element and isotopic variations in a zoned pluton and associated volcanic rocks, Unalaska Island, Alaska: a model for fractionation in the Aleutian calc-alkaline suite. Contrib Mineral Petrol 73:69–87
Pope RR, Kay SM, Kay RW (1981) Ultramafic xenoliths from Kanaga Island: insights into mantle composition and dynamics below the island arc (abs). EOS 62:1092
Reid M, Nye C (1981) Geochemistry of least fractionated basalts from Okmok volcano, central Aleutians (abs). EOS 62:1092
Shapiro L, Brannock WW (1962) Rapid analysis of silicate, carbonate and phosphate rocks. US Geol Surv Bull 1144-A:1–56
Staudigel H, Zindler A, Hart SR, Leslie T, Chen C-Y, Clague D (1984) The isotope systematics of a juvenile intraplate volcano: Pb, Nd, and Sr isotope ratios of basalts from Loihi seamount, Hawaii. Earth Planet Sci Lett 69:13–29
von Drach V, Marsh BD, Wasserburg GJ (1985) Nd and Sr isotopes in the Aleutians: multicomponent parenthood of island-arc magmas. Contrib Mineral Petrol (in press)
White WM, Patchett J (1984) Hf-Nd-Sr isotopes and incompatible element abundances in island arcs: implications for magma genesis and crust-mantle evolution. Earth Planet Sci Lett 67:167–185
Zindler A, Staudigel H, Batiza R (1984) Isotope and trace element geochemistry of young Pacific seamounts: implications for the scale of upper mantle heterogeneity. Earth Planet Sci Lett 70:175–195
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Myers, J.D., Marsh, B.D. & Sinha, A.K. Strontium isotopic and selected trace element variations between two Aleutian volcanic centers (Adak and Atka): implications for the development of arc volcanic plumbing systems. Contr. Mineral. and Petrol. 91, 221–234 (1985). https://doi.org/10.1007/BF00413349
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DOI: https://doi.org/10.1007/BF00413349