A deep mantle source for carbonatite magmatism: evidence from the nephelinites and carbonatites of the Buhera district, SE Zimbabwe

Enriched continental flood basalts from depleted mantle melts: modeling the lithospheric contamination of Karoo lavas from Antarctica

“…a Sources for the parental melt (PM CT ) parameters: for the estimation of magma liquidus T, see text; isobaric specific heat calculated on the basis of major element composition presented in Table 1 using the partial molar isobaric heat capacities listed by Spera and Bohrson (2001); crystallization enthalpy estimated using equilibrium crystallization model for the major element composition presented in Table 1 at 2 kbar (with Cr 2 O 3 = 0.3 wt%) in PELE software (Boudreau 1999). The D values for the fractionation of olivine from the parental magmas are based on those used in the PELE modeling software of Boudreau (1999) b Sources for the lower crust composition: thermodynamical parameters represent the standard lower crustal values of Bohrson and Spera (2001), except for the initial temperatures that represent values compatible with active continental rift environment (see Bohrson and Spera 2001;Chapman 1986); trace element composition after average of granulite samples 05LG10, 05LG16, and 05LG17 from the North China craton (Ying et al 2010); Nd isotopic data not available c Sources for the Archean TTG composition: thermodynamical parameters represent the standard upper crustal values of Bohrson and Spera (2001), except for the initial temperatures that represent values compatible with active continental rift environment (see Bohrson and Spera 2001;Chapman 1986); trace element composition after TTG sample 96/203 from the Kaapvaal craton (Kreissig et al 2000; Ta and Hf estimated relative to Nb and Zr, respectively, using ratios of Lana et al 2004); Nd isotopic composition after the range reported for the TTGs of the area (Kreissig et al 2000) d Sources for the SCLM1 partial melt composition: Trace element composition after average lamproite of Bergman (1987); Nd isotopic composition after the range reported for the alkaline rocks described in Harmer et al (1998) and Luttinen et al (2002) e Sources for the SCLM2 partial melt composition: Trace element composition after a representative Spitskop ijolite (S115; Harmer 1999) with Ta and Hf estimated using Nb/Ta = 17 and Zr/Hf = 46 (Chakhmouradian 2006), Th estimated using Nb/Th = 10.64 (after Buhera ijolites; Harmer et al 1998), and Tb estimated relative to other REE; Nd isotopic composition after the range reported for the alkaline rocks described in Harmer et al (1998) and Luttinen et al (2002) f Back-calculated at 159 Ma …”

“…Local ~160 Ma lamproites from Vestfjella (Luttinen et al 2002), carbonatites, nephelinites, and ijolites related to Kaapvaal SCLM and its surroundings (Harmer et al 1998;Harmer 1999), and average lamproite (Bergman 1987) were selected to represent partial melt compositions of the local fertile SCLM for AFC modeling.…”

Geochronological and isotopic constraints on the Mesoproterozoic Namaqua–Natal Belt: evidence from deep borehole intersections in South Africa

“…Rb-Sr and Sm-Nd isotope techniques utilised for this study followed those previously documented (Harmer et al, 1998). Model Nd T DM dates have been calculated using the 1991 DePaolo model for depleted mantle (DePaolo et al, 1991).…”

Fluid-rock interaction in the Kangankunde Carbonatite Complex, Malawi: SEM based evidence for late stage pervasive hydrothermal mineralisation

“…Carbonatite magmas are considered to be residual melts of fractionated carbonated nephelinite or melilitite [7,8] or immiscible melt fractions of CO 2 -saturated silicate melt [9][10][11][12][13][14]. Carbonatites are also considered primary mantle melts generated through partial melting of CO 2 -bearing peridotite [15][16][17][18][19]. They are subdivided into primary magmatic carbonatites and carbothermal residual carbonatites formed from low temperature fluids that are rich in CO 2 , H 2 O and fluorine [20].…”