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Table 2. Field and petrologic characteristics of lithologic units within the field trip area.
Lithologic Unit Rock Type(s)1 Primary Minerals2 Accessory Minerals2 Megascopic Field Characteristics2
low-silica charnockite
Yfqj
monzogranite to quartz monzodiorite (farsundite to quartz jotunite) Mipt (Mc), Pl, Qtz, Opx, Amph, Cpx Ap, Ilm, Mag, Zrn, Ep, Act medium- to very coarse-grained, massive to weakly foliated, lenticular magnetite-rich xenoliths, Af megacrysts
alkali feldspar granite
Yaf
alkali feldspar granite Af, Pl, Qtz, Bt Ttn, Fe-Ti Oxides coarse-grained, porphyritic, massive
Old Rag magmatic suite
Ygr
alkali feldspar granite to syenogranite Pt (Mc), Pl, Qtz, Opx, Grt, Bt Ap, Ilm, Mag, Zrn, Ep, Act medium- to very coarse-grained, massive to weakly foliated
garnetiferous syenogranite
Ygg
alkali feldspar granite to syenogranite Or, Pl, Qtz, Grt, Bt, Opx Ap, Ilm, Zrn medium- to very coarse-grained, weakly to locally strongly foliated, medium-grained Af dikes, rare pegmatite dikes
leucogranite gneiss
Ylgg
alkali feldspar granite Mept (Mc), Pl, gray Qtz, Bt Ilm, Mag, Zrn, Ep, Ms coarse- to very coarse-grained, strongly foliated, Mept megacrysts
biotite granitoid gneiss
Ybg
monzogranite to quartz monzonite and quartz monzodiorite Mc, Pl, Qtz, Bt Ap, Ilm, Ttn, Zrn, Ep, Chl medium- to coarse-grained, strongly foliated
Flint Hill Gneiss
Yfh
syenogranite to monzogranite Mc, Pl, Qtz, Bt, Chl Ap, Leux, Ilm, Zrn medium- to very coarse-grained, strongly foliated
foliated pyroxene granite
Yfpg
monzogranite (farsundite) Mc, Pl, Qtz, Opx, Amph, Bt Ap, Ilm, Zrn medium- to coarse-grained, strongly foliated, pegmatitic dikes, Grt leucogranite dikes
layered granodiorite gneiss
Ylgn
granodiorite (opdalite) Mc, Or, Pl, Qtz, Amph, Opx Ap, Ilm, Zrn medium- to coarse-grained, strongly foliated, gneissic layers locally folded, massive leucogranite sheets, boudins
pyroxene quartz diorite
Ypqd
quartz diorite (orthopyroxene quartz diorite) Or, Pl, Qtz, Opx, Bt Ap, Mag, Zrn medium-grained, moderately to strongly foliated, gneissic layering
high-silica charnockite
Ycf
syenogranite to monzogranite (charnockite to farsundite) Mipt, Pl, Qtz, Opx, Amph, Cpx Ap, Ilm, Mag, Zrn, Ep, Act coarse- to very coarse-grained, moderately to strongly foliated, locally prominent gneissic layering, Af megacrysts
garnetiferous granite gneiss
Yg
syenogranite to monzogranite Mipt, Pl, Qtz, Opx, Grt, Bt, Cpx Ap, Ilm, Mag, Zrn, Chl medium- to coarse-grained, strongly foliated, prominent gneissic layering
garnetiferous gneiss
Ygn
granodiorite (opdalite)? Af, Pl, Qtz, Gt, Opx Ttn, Fe-Ti Oxides fine- to coarse-grained, layered
(1) foliated megacrystic leucocratic granite
(2) leucogranite
Ylg
alkali feldspar granite to syenogranite 1) Mept (Mc & Or), Pl, Qtz, intergrown Bt & Chl
2) Mc, Pl, Qtz, minor secondary Bt
Zrn, Ep, Ttn (1): coarse-grained, strongly foliated
(2): medium-grained, massive to weakly foliated
Unit also includes coarse-grained leucogranite pegmatite

1Rock types determined using molar normative compositions calculated on basis of Fe2+/Fe(total) = 0.9 plotted on Q' vs ANOR diagram of Streckeisen and Le Maitre (1979). Charnockitic nomenclature included in parentheses following recommendations of Le Maitre and others (1989).
2Abbreviations: Af, alkali feldspar; Leux, leucoxene; Mipt, microperthite; Mept, mesoperthite; Pt, perthite. Other abbreviations after Kretz (1983): Act, actinolite; Aln, allanite; Amph, amphibole; Ap, apatite; Bt, biotite; Cal, calcite; Chl, chlorite; Cpx, clinopyroxene; Ep, epidote; Fl, fluorite; Grt, garnet; Ilm, ilmenite; Mag, magnetite; Mc, microcline; Or, orthoclase; Opx, orthopyroxene; Pl, plagioclase; Qtz, quartz; Ttn, titanite; Zrn, zircon.


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