Sample SP70

Minette

Major Element Data

SiO2 TiO2 Al2O3 Fe2O3 FeO MnO MgO CaO Na2O K2O P2O5 Total
48.31 2.91 11.82 1.61 7.73 0.12 5.23 10.78 3.15 4.60 3.86 100.12

(After normalizing for H2O+,L.O.I,and CO2. FeO and Fe2O3 normalized to NNO Buffer.)

Minor Element Data

Rb Sr Ba La Ce Nd Sm Eu Gd Yb Lu Sc Cr Ni Zr Nb Th
52.9 1380 2520 107 262 129 18.9 4.39 11.3 1.15 0.154 11.8 98.5 73.3 385 106 6.4

(PPM)

REE Data

Sample La Ce Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
sp70 107.000 262.000 129.000 18.900 4.390 11.300 1.050 0.000 1.150 0.154
sp70b 109.000 271.000 132.000 19.500 4.510 11.200 1.060 0.807 0.000 1.210 0.151

(Raw data values in ppm - need to correction to chondrite values)

Radiogenic Data

87Rb/86Sr error 87Sr/86Sr error 87Sr/86Sri
0.1430 0.0024 0.7046 0.0002 0.7046

147Sm/144Nd error 143Nd/144Nd error EpsilonNd
0.0878 0.0001 0.5124 0.00002 -4.50

206Pb/204Pb error 207Pb/206Pb error 208Pb/206Pb error 207Pb/204Pb error 208Pb/204Pb error
17.5650 0.0120 0.8793 0.0003 2.1168 0.0013 15.4450 0.0150 37.1820 0.0460

(PPM)

40Ar/39Ar age spectra for SP70

Thin-section description

SP70. Minette. This rock is hypocrystalline, porphyritic-aphanitic with fine- to medium-grained phenocrysts in a grey-brown groundmass (36%) of mostly orthoclase and pyroxene. All crystals are subhedral except the opaque minerals (<1 mm), and analcite (<1 mm), which are subhedral to anhedral. Carbonate, chlorite, and epidote are present as anhedral masses (all < 1 mm). The following are present as phenocryst phases: biotite (.5 to 2.5 mm) are the dominant phenocryst phases; zoned titanaugite (< .5 mm), minor amounts of orthopyroxene (< .5 mm) and variolitic augite (<.1 mm); orthoclase (< 1 mm); apatite (<1 mm). Some of the medium mica grains have inclusions of orthoclase and a few others exhibit a sieve-like texture. Some of the orthoclase crystals have micro-perthite stringlets. There are some stellate clusters of titanaugite (<.5 mm). Epidote and chlorite are primarily associated with mica crystals. Amygdules (<1 mm) are scattered throughout the thin section with cores of calcite and analcite surrounded by inward pointing acicular augite (.1 mm) crystals. The overall texture is trachytic. Biotite was the phase dated.