Mantle Xenoliths Chondritic Meteorite + Iron Metal Iron basalt or granite crust peridotite mantle olivine feldspar = Sun

oliv opx cpx Mantle Xenoliths nephelinite Refractory Mantle Residues Chondritic Meteorites Solar Composition chondrules

Sun B ulk S ilicate E arth (~68 wt.%) + Fe-metal core (~31 wt.%) The Earth’s upper mantle is similar in composition to BSE, and is composed of a rock called peridotite, which consists largely of the minerals olivine and orthopyroxene basalt or granite crust Fe-Ni metallic core peridotite mantle SiO 2 + MgO + FeO ~ 91% Sun - Chondritic Meteorites - Earth’s Mantle ~

Igneous Petrology Lab 3: The Mantle Source and Primary Magmas

Apatite = P 5+ / 3 Cpx (XYT 2 O 6 ) = X = (Ca 2+ + Na + + K + ) - 5 x Apatite Spinel (Y 2+ Y 3+ 2 O 4 ) = Y 3+ /2 = Cr 3+ /2 + (Al Ti 4+ - Na + )/2. Opx* (Y 2 T 2 O 6 ) = Y/2 = ((Mg 2+ + Fe 2+ + Mn 2+ + Ni 2+ + Co 2+ ) - Spin - Cpx)/2 Si* = Si x Cpx - 2 x Opx* + Ti 4+ If Si* is negative: Oliv (Y 2 TO 4 ) = - Si* Si* = Opx = Opx* - Oliv If Si* is positive: Qtz = Si* Oliv = 0.0 Opx = Opx* In order to plot your points, orthopyroxene must be recalculated as a mixture of olivine and quartz. Calculation for plotting in Olivine – Clinopyroxene – Quartz Liquidus Projection

Solid Source Refractory Solid + Liquid Restite Refractory Mantle + Oceanic Crust Cpx-rich Peridotite Lherzolite Olivine-rich Peridotite + Basalt Harzburgite Partial Melting of the Mantle Fertile Mantle Whole = Σ Parts Lever Rule: p/R = x/y y x R amount of basalt (P) in fertile mantle = x/(x+y) ~ 15-20%

opx cpx

Calculate an ideal Cpx formula: XYT 2 O 6 : cations sum to 4 Al (1V) = 2 – Si Al (VI) = Al - Al (1V) CrCaTs ( CaCrAlSiO 6 ) = Cr AlCaTs ( CaAl 2 SiO 6 ) = Al (VI) – CrCaTs – Na Jadeiite ( NaAlSi 2 O 6 )= Na Wo ( CaSiO 3 )= (Ca - AlCaTs – CrCaTs)/2 En ( MgSiO 3 ) = (1-Wo-Jd) × X Mg where X Mg = Mg/(Fe+Mg) Fs ( FeSiO 3 ) = (1-Wo-Jd) × (1-X Mg ) Clinopyroxene component calculation

opx cpx

Estimation of Pressure or Depth of Origin