Part 9 ! Fig. 108. Needle Peak diatreme and dike viewed from the west. ! Fig. 109. Crustal xenoliths in Needle Peak diatreme. Needle Peak diatreme !368 Eastern termination of W-E dike, choked with crustal xenoliths. Long & Lat Quadrangle 104 47, 30 42.5 Ninetysix Ranch Related to Rim Rock dikes? !Reference: Dasch et al., 1969 !Miocene dikes and lavas associated with Basin-and-Range faulting Sample SM84051 Alkali basalt plug. According to C.D. Henry (personal communication, 2003), this is part of the ~24 Ma Basin & Range-related intrusions, not related to Sawmill Mountain. - SiO2 TiO2 AL2O3 Fe203 FeO FeO* MnO MgO CaO Na2O K2O P2O5 H2O+ H2O CO2 LOI Total 45.10 2.14 14.50 2.92 7.00 9.63 0.16 10.10 9.85 3.63 0.97 0.16 1.50 0.30 0.10 98.88 Sc V Ni Cu Zn Rb Sr Y Zr Nb Cs Ba La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb 30 810 20 180 60 Lu Hf Ta Pb Th U MALI @ SiO2 (Na2O+K2O) A.I. Mg# Nb/Zr Y/Nb -5.11 46.50 4.74 0.49 51.2 0.33 0.33 !Ross and Lambert, 1986 Mafic dike north of Terlingua This contains spinel lherzolite and crustal xenoliths, and olivine, clinopyroxene, plagioclase, magnetite and ilmenite. Long & Lat Quadrangle Age, Ma: 24.1 ±0.6 (K-Ar, plagioclase) 103°35.7’, 29°22.2’ Terlingua Sample 8204 Hawaiite. - SiO2 TiO2 Al2O3 Fe203 FeO FeO* MnO MgO CaO Na2O K2O P2O5 H2O+ H2O CO2 LOI Total 46.37 2.20 15.92 1.07 8.90 9.86 0.16 9.35 9.92 4.19 1.35 0.58 100 Sc V Ni Cu Zn Rb Sr Y Zr Nb Cs Ba La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er 228 25 775 28 209 65 0.43 2613 62.4 119 49.5 8.71 2.72 1.47 Tm Yb Lu Hf Ta Pb Th U 2.19 0.34 5.62 2.09 5.82 MALI @ SiO2 (Na2O+K2O) A.I. Mg# Ce Ce/Yb Ta/Yb Th/Yb -4.28 46.37 5.54 0.53 49 197.3 14.7 0.95 2.66 Nb/Zr Zr/Hf Nb/Ta Y/Nb La/Y 206Pb/204Pb 207Pb/204Pb 208Pb/204 Pb 0.31 37.2 31.1 0.43 2.23 18.471 15.527 38.034 Henry et al., 1986; Schucker and Nelson, 1988; James and Henry, 1993; !Henry, Price and Miser, 1989 Sample H-1 Hawaiite intrusion, same dike - SiO2 TiO2 Al2O3 Fe203 FeO FeO* MnO MgO CaO Na2O K2O P2O5 H2O+ H2O CO2 LOI Total 46.00 2.20 13.70 2.10 8.60 10.49 0.17 8.90 9.80 3.30 1.90 0.855 1.70 99.22 Sc V Ni Cu Zn Rb Sr Y Zr Nb Cs Ba La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb 28.92 84 34.8 773 177 0.58 634 46.24 82.3 39.8 Lu Hf Ta Pb Th U 3 7 MALI @ SiO2 (Na2O+K2O) A.I. Mg# Ce Ce/Yb Ta/Yb Th/Yb Zr/Hf -4.56 46.36 5.24 0.55 45.9 136.5 6.83 1.01 1.42 40.2 !Nelson and Schieffer, 1989 !369 Dike on Forbidden Mountain Sample DM104 Hawaiite with lherzolite xenoliths. Long & Lat Quadrangle Age, Ma: 24 103°59.0’, 30°50.0’ Little Aguja Mtn - SiO2 TiO2 Al2O3 Fe203 FeO FeO* MnO MgO CaO Na2O K2O P2O5 H2O+ H2O CO2 LOI Total 46.33 1.97 14.48 1.81 7.48 9.11 0.16 10.44 11.57 4.11 1.22 0.96 100.53 Sc V Ni Cu Zn Rb Sr Y Zr Nb Cs Ba La Ce Pr Nd Sm Eu Gd Tb 27.82 67 97.1 37.8 1034 38.5 218 31.6 0.33 1790 52.3 100 37.1 7.64 2.48 1.27 Dy Ho Er Tm Yb Lu Hf Ta Pb Th U 2.44 0.31 4.18 3.23 4.8 1.5 MALI @ SiO2 (Na2O+K2O) A.I. Mg# Ce Ce/Yb Ta/Yb Th/Yb -6.24 46.33 5.33 0.59 53 165.8 12.0 1.44 2.14 Nb/Zr Zr/Hf Nb/Ta Y/Nb La/Y Y/Sc 206Pb/204Pb 207Pb/204Pb 208Pb/204 Pb 0.14 52.2 9.78 1.22 1.36 1.38 17.477 15.471 37.251 !James and Henry, 1993 Intrusion cutting Closed Canyon lavas Age, Ma: 20.0 ±0.4 (K/Ar, whole rock) Tephrite/basanite Long and Lat Quadrangle Sample H90-68 103 51.1, 29 25.2 Bandera Mesa S - SiO2 TiO2 Al2O3 Fe203 FeO FeO* MnO MgO CaO Na2O K2O P2O5 H2O+ H2O CO2 LOI Total 46.10 2.63 15.95 11.28 0.19 7.04 9.63 4.41 1.59 1.20 97.56 Sc V Ni Cu Zn Rb Sr Y Zr Nb Cs Ba La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er 21 136 87 31 82 40 1199 27 168 75.1 1042 51 94 10.6 44.5 9.4 3.21 7.8 1 5.96 1.07 2.76 Tm Yb Lu Hf Ta Pb Th U 0.33 1.88 0.25 2.6 1.1 2.8 4.2 1 MALI @ SiO2 (Na2O+K2O) A.I. Mg# Ce Eu* Ce/Yb Ta/Yb Th/Yb -3.63 46.10 6.00 0.56 38.4 155.9 1.1 13.5 0.59 2.23 Nb/Zr Zr/Hf Nb/Ta Y/Nb La/Y Y/Sc 0.45 64.6 68.3 0.36 1.89 1.29 !Henry et al., 1998 Sill in SE corner, Christmas Mountains quadrangle Nepheline-normative hawaiite Long & Lat Quadrangle Age, Ma: 28.1 ±0.6 (K-Ar, whole rock) 103°37.0’, 29°23.5’ Christmas Mtns Sample H86-35 !Henry, Price and Miser, 1989 !Miocene Black Gap lavas Up to 150 m thick, composed of many thin flow units, with plagioclase + titanaugite + skeletal olivine phenocrysts (the last commonly altered to iddingsite). Extruded after Basin & Range faulting had begun. Long & Lat Quadrangle Age, Ma: 21.84 ± 0.68 102°56.0’, 29°35.0’ Black Gap Sample 77040 Alkali basalt massive central part of the next-to-lowest flow unit exposed. - SiO2 TiO2 Al2O3 Fe203 FeO FeO* MnO MgO CaO Na2O K2O P2O5 H2O+ H2O CO2 LOI Total !370 48.88 2.14 14.91 6.63 4.09 10.06 0.13 6.69 7.90 3.37 1.41 0.61 1.77 0.53 0.24 99.50 Sc V Ni Cu Zn Rb Sr Y Zr Nb Cs Ba La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb 107 96 28 750 24 110 612 Lu Hf Ta Pb Th U MALI @ SiO2 (Na2O+K2O) A.I. Mg# -2.97 50.41 4.93 0.48 40.6 !unpublished Sample 77041 Alkali basalt from 8 meters above 77040, in another flow unit. - SiO2 TiO2 Al2O3 Fe203 FeO FeO* MnO MgO CaO Na2O K2O P2O5 H2O+ H2O CO2 LOI Total 49.03 1.76 14.76 7.92 3.33 10.46 0.09 6.77 8.50 3.56 0.92 0.51 1.27 0.76 0.05 99.20 Sc V Ni Cu Zn Rb Sr Y Zr Nb Cs Ba La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb 113 100 580 22 120 14 411 Lu Hf Ta Pb Th U MALI @ SiO2 (Na2O+K2O) A.I. Mg# Nb/Zr Y/Nb -3.89 50.46 4.61 0.46 39.3 0.12 1.57 !unpublished Sample 77042 Alkali basalt from 15 meters above 77041, in another flow unit. - SiO2 TiO2 Al2O3 Fe203 FeO FeO* MnO MgO CaO Na2O K2O P2O5 H2O+ H2O CO2 LOI Total 49.34 1.68 15.27 6.78 4.01 10.11 0.16 6.81 8.15 3.38 0.87 0.46 1.52 0.50 0.20 99.13 Sc V Ni Cu Zn Rb Sr Y Zr Nb Cs Ba La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er 20.15 165 110 13 520 23 97 20 0.18 371 18.99 38.15 27 4.52 1.53 0.78 Tm Yb Lu Hf Ta Pb Th U 1.56 0.23 2.92 1.6 2.92 1.18 MALI @ SiO2 (Na2O+K2O) A.I. Mg# Ce Ce/Yb Ta/Yb Th/Yb -3.9 49.34 4.25 0.43 40 63.3 6.62 1.03 1.87 Nb/Zr Zr/Hf Nb/Ta Y/Nb La/Y 206Pb/204Pb 207Pb/204Pb 208Pb/204 Pb Y/Sc 0.21 33.2 12.5 1.15 0.83 18.432 15.582 38.231 1.14 !James and Henry, 1991; James and Henry, 1993 ! ! Yellow Hill quadrangle, Hill 3308 Long & Lat Quadrangle Age, Ma: 20.2 ± 0.7 (K-Ar, whole rock) 103°39.1’, 29°23.9’ Yellow Hill Sample H85-41A !Henry, Price and Miser, 1989 Tib-1 Sample Tib-1 Tephrite/basanite intrusion cutting Rawls Formation. Contains phenocrysts of olivine and sector-zoned Ti- and Al-rich clinopyroxene. Long & Lat Quadrangle Age, Ma: 17.6 ± 0.3 (K-Ar, whole rock) 104°09.5’, 29°36.0’ Cerro Redondo - SiO2 TiO2 Al2O3 Fe203 FeO FeO* MnO MgO CaO Na2O K2O P2O5 H2O+ H2O CO2 LOI Total 44.7 2.61 14.89 2.61 7.95 10.30 0.19 7.07 9.42 3.21 1.47 1.20 2.40 0.24 0.01 99.22 Sc V Ni Cu Zn Rb Sr Y Zr Nb Cs Ba La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm 19.8 140 66 33 1060 60 150 85 0.44 690 41.8 89.47 53 8.69 2.85 1.1 Yb Lu Hf Ta Pb Th U 1.9 028 3.67 2.9 3.68 1.4 MALI @ SiO2 (Na2O+K2O) A.I.