Abstract
The Sr and Nd isotopic ratios of Central American volcanics can be described by the mixing of four components, marine sediment from DSDP Site 495, MORB-source mantle (DM), EMORB-source mantle (EM), and continental crust. Most of the isotopic data define a trend between EM and a modified mantle (MM) formed as a mixture of DM and less than 0.5% marine sediment, or fluid derived there from. The MM to EM trend is equally apparent in the incompatible-element data and is most clearly seen in a Ba/La versus La/Yb plot. A hyperbolic trend connects high Ba/La and low La/Yb at the MM end of the trend to low Ba/La and high La/Yb at the EM end. Smooth regional variations in incompatible-element and isotopic ratios correlate with the dip of the subducted slab beneath the volcanic front and the volume of lava erupted during the last 100,000 years (volcanic flux). Steep dip and low flux characterize the MM end-member and shallow dip and high flux characterize the EM end-member. The simplest model to explain the linked tectonic and geochemical data involves melting in the wedge by two distinct mechanisms, followed by mixing between the two magmas. In one case, EM magma is generated by decompression of EM plus DM asthenosphere, which is drawn in and up toward the wedge corner. EM mantle is preferentially melted to small degrees because of the presence of low melting components. The second melt is formed by release of fluid from the subducted slab beneath the volcanic front to form MM magma. Mixing between EM and MM magmas is controlled by subduction angle, which facilitates delivery of EM magma to the volcanic front at low-dip angles and impedes it at steep-dip angles.
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References
Bennett EA, Carr MJ, Feigenson MD (1989) Nb and Be contents of Central American lavas. EOS Trans Am Geophys Union 70:504
Boer J de, Defant MJ, Stewart RH, Restrepo JF, Clark LF, Ramirez AH (1988) Quaternary calc-alkaline volcanism in western Panama: regional variation and implication for plate tectonic framework. J South Am Earth Sci 1:275–293
Brown L, Klein J, Middleton R, Sacks IS, Tera F (1982) 10Be in island arc volcanoes and implications for subduction. Nature 299:718–720
Carr MJ (1976) Underthrusting and Quaternary faulting in northern Central America. Geol Soc Am Bull 88:151–156
Carr MJ (1977) Volcanic activity and great earthquakes at convergent plate boundaries. Science 197:655–657
Carr MJ (1984) Symmetrical and segmented variation of physical and geochemical characteristics of the Central American volcanic front. J Volcanol Geotherm Res 20:231–252
Carr MJ, Rose WI (1987) CENTAM-a data base of analyses of Central American volcanic rocks. J Volc Geotherm Res 33:239–240
Dewey JW, Algermissen ST (1974) Seismicity of the Middle America arc-trench system near Managua, Nicaragua. Bull Seismol Soc Am 64:1033–1048
Feigenson MD, Carr MJ (1985) Determination of major, trace and rare-earth elements in rocks by DCP-AES. Chem Geol 51:19–27
Feigenson MD, Carr MJ (1986) Positively correlated Nd and Sr isotope ratios of lavas from the Central American volcanic front. Geology 14:79–82
Gill J (1981) Orogenic andcsites and plate tectonics. Springer, New York Berlin Heidelberg New York
Grant NK, Rose WI, Fultz LA (1984) Correlated Sr isotope and geochemical variations in basalts and basaltic andesites from Guatemala. In: Harmon RS, Barreiro BA (eds) Andean magmatism, chemical and isotopic constraints. Birkhäuser, Cambridge, pp 139–149
Guendal FD (1986) Seismotectonics of Costa Rica: an analytical view of the southern terminus of the Middle American Trench. PhD thesis, University of California, Santa Cruz
Hildreth W, Moorbath S (1988) Crustal contributions to arc magmatism in the Andes of Central Chile. Contrib Mineral Petrol 98:455–489
Huene R von, Aubouin J, Azema J, Blackington G, Carter JA, Coulbourn WT, Cowan DS, Curiale JA, Dengo CA, Faas RW, Harrison W, Hesse R, Hussong DM, Ladd JW, Muzylov N, Shiki T, Thompson PR, Westberg J (1980) Leg 67: The Deep Sea Drilling Project Mid-America Trench transect off Guatemala. Geol Soc Am Bull 91:421–432
Ikeda Y, Yuasa M (1989) Volcanism in nascent back-arc basins behind the Shichito Ridge and adjacent areas in the Izu-Ogasawara arc, northwest Pacific: evidence for mixing between Etype MORB and island arc magmas at the initiation of back-arc rifting. Contrib Mineral Petrol 101:377–393
Kay RW (1980) Volcanic arc magmas: implications of a melting-mixing model for element recycling in the crust-upper mantle system. J Geol 88:497–522
Kushiro I (1987) A petrological model of the mantle wedge and lower crust of the Japanese island arcs. In: Mysen BO (ed) Magmatic processes: physiochemical principles. Geochemical Society, Dayton, Ohio, Spec Pub 1, pp 165–181
Kussmaul S, Paniagua S, Gainsa J (1982) Recopilacion, clasificacion, e interpretacion petroquimica de las rocas de Costa Rica. Informe Sem Inst Geograf Nac, San Jose, Costa Rica 28:17–79
Le Roex AP, Dick HJB, Erlank AJ, Reid AM, Frey FA, Hart SR (1983) Geochemistry, mineralogy and petrogenesis of lavas along the southwest Indian Ridge between the Bouvet triple junction and 11 degrees East. J Petrol 24:267–318
McBirney AR, Williams H (1965) Volcanic history of Nicaragua. Univ Calif Publ Geol Sci 55:1–65
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 47:2015–2033
Morris JD, Tera F (1989) 10Be and 9Be in mineral separates and whole rocks from volcanic arcs: implications for sediment subduction. Geochim Cosmochim Acta 53:3197–3206
Nakamura E, Campbell IH, McCulloch MT, Sun SS (1989) Chemical geodynamics in a back arc region around the sea of Japan: implication for the genesis of alkaline basalts in Japan, Korea and China. J Geophys Res 94:4634–4654
Nakamura N (1974) Determination of REE, Ba, Fe, Mg, Na, and K in carbonaceous and ordinary chondrites. Geochim Cosmochim Acta 38:757–775
Nye CJ, Reid MR (1986) Geochemistry of primary and least fractionated lavas from Okmok volcano, Central Aleutians: implications for arc magmagenesis. J Geophys Res 91:10271–10288
Nystrom JO, Levy B, Troeng B, Ehrenborg J, Carranza G (1988) Geochemistry of volcanic rocks in a traverse through Nicaragua. Rev Geol Am Cent 8:77–110
O'Nions RK, McKenzie DP (1988) Melting and continent generation. Earth Planet Sci Lett 90:449–456
Plank T, Langmuir CH (1988) An evaluation of the global variations in the major element chemistry of arc basalts. Earth Planet Sci Lett 90:349–370
Prosser JT, Carr MJ (1987) Poas volcano, Costa Rica: Geology of the summit region and spatial and temporal variations among the most recent lavas. J Volc Geotherm Res 33:131–146
Reagan MK, Gill JB (1989) Coexisting calcalkaline and high-niobium basalts from Turrialba volcano, Costa Rica: implications for residual titanates in arc magma sources. J Geophys Res 94:4619–4633
Spiegelman M, McKenzie D (1987) Simple 2-D models for melt extraction at mid-ocean ridges and island arcs. Earth Planet Sci Lett 83:137–152
Stoiber RE, Carr MJ (1973) Quaternary volcanic and tectonic segmentation of Central America. Bull Volcanol 37:304–325
Tasumi Y, Sakuyama M, Fukuyama H, Kushiro I (1983) Generation of arc basalt magmas and thermal structure of the mantle wedge in subduction zones. J Geophys Res 88:5815–5825
Tatsumi Y, Hamilton DL, Nesbitt RW (1986) Chemical characteristics of fluid phase released from a subducted lithosphere and origin of arc magmas: evidence from high pressure experiments and natural rocks. J Volcanol Geotherm Res 29:293–309
Thompson RN, Morrison MA, Hendry GL, Parry SJ (1984) An assessment of the relative roles of crust and mantle in magmagenesis. Philos Trans R Soc Lond A310:549–590
Tournon J (1973) Presence de basaltes alcalines recents au Costa Rica (Amerique Central). Bull Volcanol 36:140–147
Wadge G (1984) Comparison of volcanic production rates and subduction rates in the Lesser Antilles and Central America. Geology 12:555–558
Walker JA (1981) Petrogenesis of lavas from cinder cone fields behind the volcanic front of Central America. J Geol 87:721–739
Walker JA (1984) Volcanic rocks from the Nejapa and Granada cinder conc alignments, Nicaragua, Central America. J Petrol 25:299–342
Walker JA (1989) Caribbean arc tholeiites. J Geophys Res 94:10539–10548
Walker JA, Carr MJ, Feigenson MD, Kalamarides RI (1990) The petrogenetic significance of interstratified high- and low-Ti basalts in central Nicaragua. J. Petrol (in press)
Wood DA (1979) A variably veined suboceanic upper mantle-Genetic significance for mid-ocean ridge basalts from geochemical evidence. Geology 7:499–503
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Carr, M.J., Feigenson, M.D. & Bennett, E.A. Incompatible element and isotopic evidence for tectonic control of source mixing and melt extraction along the Central American arc. Contrib Mineral Petrol 105, 369–380 (1990). https://doi.org/10.1007/BF00286825
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DOI: https://doi.org/10.1007/BF00286825