SOUTH HARTFORD BASIN, CONNECTICUT

Twenty-three (23) whole rock samples of diabase from the West Rock and Barndoor sheets were collected by Froelich in 1988 and analyzed by the U.S. Geological Survey. Samples labeled WR-1-13 and BD-1-10 on the map are the same as those labeled FG-88-WR-1-13 and FG-88-BD-1-10 in the tables. The palladium (Pd) and platinum (Pt) abundances and ratios in the chilled margins of the West Rock and Barndoor sheets, the two northernmost diabase sheets in the eastern North America (ENA) tholeiite province, are typical of those in high Ti, quartz normative (HTQ) magmas throughout the province. Platinum contents are greater than palladium in the orthopyroxene cumulate zones, and Pd is greater than Pt in the late-stage differentiates. In other HTQ sheets further south Pd is locally enriched in ferrogabbros. Unfortunately, the late-stage, iron-rich quartzose gabbros of the Barndoor sheet, mapped and studied by Kroll, 1976, were not sampled during this study; thus, it is uncertain if anomalous Pd enrichment is present in any part of the diabase sheets of the South Hartford basin.

References

Kroll, R.L., 1976, Barndoor diabase intrusions, north-central Connecticut: Geological Society of America Bulletin, v. 87, p. 1449-1454.

Southern Hartford Basin text file

SOUTH HARTFORD BASIN, CONNECTICUT
SAMPLE MAGMA TYPE DESCRIPTION
FG-88-WR-1 High Ti, quartz normative

West Rock sheet
Table la, lb

Cumulate
FG-88-WR-2    Cumulate
FG-88-WR-3    Cumulate
FG-88-WR-4    Cumulate
FG-88-WR-5   Basal  chill
FG-88-WR-6   Upper  chill
FG-88-WR-7    Diabase
FG-88-WR-8    Upper chill
FG-88-WR-9    Diabase
FG-88-WR-10    Diabase
FG-88-WR-11    Diabase
FG-88-WR-12    Upper apophysis
     
FG-88-BD-1 Barndoor Sheet
Table2
Cumulate  
FG-88-BD-2 Diabase  
FG-88-BD-3 Lower chill
FG-88-BD-4 Diabase  
FG-88-BD-5 Diabase  
FG-88-BD-6 Diabase  
FG-88-BD-7 Cumulate  
FG-88-BD-8 Upper chill
FG-88-BD-9 Upper chill
FG-88-BD-10 Altered diabase

Tablela.SouthHartfordbasin,Connecticut.WestRock
  W-244939 W-244940 W-244941 W-244942 W-244943 W-24494   W-244945  
  FG-88 FG-88 FG-88 FG-88 FG-88 FG-88 FG-88
  WRl WR2 WR3 WR4 WR5 WR6 WR7
Lat. 41°25'N 41°25'N 41°25'N 41°25'N 41°25'N 41°28'N 41°28'N
Long. 72°57'W 72°57'W 72°57'W 72°57'W 72°57'W 72°56'W 72°56'W
SiO2 52 51.6 51.9 52 52.1 51.9 52.2
TiO2 1.25 1.2 1.25 1.11 1.14 1.15 1.17
A12O3 15.6 16 14.8 13.9 13.8 14.1 14.5
Fe2O3 3.65 3.27 3.17 2.93 2.51 3.07 2.97
FeO 7.8 7.3 7.8 7.9 8 7.6 7.8
MnO 0.17 0.16 0.17 0.17 0.17 0.21 0.17
MgO 5.6 5.7 6-.59 8.07 7.82 7.23 7.09
CaO 10.9 11.2 11 11 11.1 11 10.6
Na2O 2.21 2.08 2.3 1.9 1.93 1.97 2.24
K2O 0.56 0.51 0.66 0.6 0.51 0.56 0.64
P2O5 0.16 0.15 0.15 0.13 0.14 0.14 0.15
H2O+ 0.93 0.92 0.98 0.65 0.65 0.98 0.65
H2O- 0.27 0.28 0.22 0.27 0.29 0.19 0.35
CO2 <0.01 <0.01 <0.01 <0.01 <0.01 0.29 0.01
S 0.03 0.04 0.06 0.02 0.03 0.04 0.04
F 0.02 0.02 0.02 0.02 0.02 0.02 0.02
Cl 0.01 0.01 0.01 0 0 0 0
? 101.15 100.43 101.08 100.67 100.21 100.45 100.6
Sc (ppm) 35 33 36 37 36 36 36
Cr 137 155 250 430 320 270 270
Co 45 42 45 49 46 46 46
Ni 67 66 79 110 94 87 81
Zn 83 70 71 68 72 73 69
Ga 22 21 19 19 19 19 19
As 2 <0.70 <0.80 0.84 1.6 <1.30 <0.90
Rb 22 20 31 27 23 22 28
Sr 210 200 200 180 190 180 200
Sb <0.130 0.15 <0.40 0.21 <0.130 0.26 <0.120
Cs 1.5 0.81 0.89 0.9 1 0.99 0.96
Ba 170 160 160 150 150 150 190
Y 22 21.6 21 19 20 20 20
La 12 11.3 11.9 10.1 10.5 10.7 11.1
Ce 24.6 23.6 25 21 22 23 23
Nd 15 12 14 12 10 <21.0 12
Sm 3.7 3.6 3.7 3.2 3.3 3.5 3.6
Eu 1.16 1.1 1.16 0.93 1 1.1 1.1
Tb 0.7 0.65 0.66 0.59 0.63 0.63 0.63
Yb 2.4 2.4 2.2 2.1 2.1 2.3 2.4
Lu 0.33 0.34 0.34 0.31 0.32 0.32 0.3
Hf 2.76 2.6 2.7 2.3 2.5 2.8 2.5
Nb 8.1 7.7 7.3 5.9 7.1 7.4 7.4
Ta 0.55 0.51 0.6 0.45 0.49 0.51 0.52
Th 2.31 2.1 2.3 1.9 1.8 2.2 2.2
U 0.55 0.42 <0.50 0.42 0.49 0.35 <0.40
Pd (ppb) 8.3 - - - - 11 -
Pt 8.7 - - - - 10 -
Rh 0.6 - - - - 0.7 -
               
Ru <0.5 - - - - <0.5 -
Ir <0.5 - - - - <0.5 -
Au <11.0 <5.0 <7.0 23 8.7 9.1 <11.0

 

 

Table  lb. South Hartford basin, Connecticut West Rock
W-244946 W-244947 W-244948 W-244949 W-244950 W-244951 
FG-88 FG-88 FG-88 FG-U FG-88 FG-88 
WR8 WR9 WRIO WRII WR12  WR13
Lat. 41°30'N 41°30'N 41°30'N 41°30'N 41°32'N 41°34'N
Long. 72°55'W 72°55'W 72°55'W 72°55'W 72°53'W 72°52'W
SiO2 52 52.3 51.9 51.1 52.1 51.4
TiO2 1.16 1.12 1.33 1.3 1.44 1.09
A12O3 4.1 14.6 15.7 15.4 14.3 13.8
Fe2O3 3.13 2.57 3.11 2.95 3.77 3.1
FeO 7.5 7.8 7.7 8.1 7.7 7.7
MnO 0.27 0.18 0.18 0.17 0.18 0.18
MgO 7.6 7.14 5.38 5.33 5.55 7.82
CaO 10.6 11.1 10.8 9.86 8.95 8.22
Na2O 1.93 2.09 2.43 2.97 2.75 2.01
K2O 0.58 0.55 0.62 0.86 1.36 1.6
P2O6 0.15 0.15 0.16 0.15 0.18 0.13
H20+ 0.91 0.41 0.59 0.97 1.2 1.5
H20- 0.29 0.4 0.33 0.33 0.36 0.23
CO2 0.08 0.01 0.02 0.15 0.02 0.01
S 0.02 0.03 0.04 0.04 0.03 0.01
F 0.02 0.02 0.02 0.03 0.03 0.02
Cl 0 <0.00 <0.00 0.01 0.01 0
? 100.25 100.47 100.31 99.71 99.92 98.82
Sc (ppm) 36 36 33 35 35 36
Cr 260 240 113 62 70 26ra
Co 45 44 42 44 42 44
Ni 86 77 58 58 51 81
Zn 72 67 76 80 84 73
Ca 20 20 21 23 21 19
As <0.90 <0.90 <0.90 0.96 1.5 1.1
Rb 21 25 26 30 46 25
Sr 180 210 230 320 290 190
Sb <0.120 <0.120 0.3 0.21 0.18 0.16
Cs 0.66 0.48 0.5 1.7 0.52 0.75
Ba 160 160 170 230 270 170
Y 20 20 22 24 25 22
La 10.6 10 12.6 12.9 13.5 11.9
Ce 21.5 21.b 26 27.1 27 25
Nd 12 12 16 15 15.01 13
Sm 3.4 3.3 3.9 4.1 4.3 3.7
Eu 1.1 1.1 1.2 1.27 1.27 1.1
Tb 0.57 0.61 0.72 0.72 0.76 0.63
Yb 2.3 2.1 2.5 2''40 2.6 2.2
Lu 0.36 0.31 0.35 0.4 0.37 0.34
Hf 2.4 2.4 2.89 3 3 2.7
Nb 6.9 6.9 8.2 8.5 9 8.1
Ta 0.49 0.46 0.6 0.59 0.63 0.61
Th 2.2 2 2.4 2.7 2.5 2.4
U 0.51 0.47 0.53 0.45 0.69 <0.70
Pd (ppb) - - - - 13 -
Pt - - - - 8.8  
Rh - - - - 0.5  
Ru - - - - <0.5  
Ir - - - - <0.5  
Au 6.8 <5.0 <5.0 <3.0 13 <7.0

 

 

South Hartford basin, Connecticut. Barndoor sheet.     

  W-244952 W-244953 W-244954 W-244955 W-244956 W-244957 W-244958 W-244959 W-244960 W-244961
  FG-88 FG-88 FG-88 F"8 FG-88 FG-88 FG-88 FG-88 FG-88 FG-88
  BD1 BD2 BD3 BD4 BD5 BD6 BD7 BD8 BD9 BDIO
Lat. 41°48'N 41°348'N 41°48'N 41°49'N 41°49'N 41°49N 41°50'N 41°55'N 41°58'N 41°58'N
Long. 72°0'W 72°0'W 72°0'W 72°52'W 72°52'W 72°52'W 72°52'W 72°49'W 72°47'W 72°47'W
SiO2 52 52 51.9 51.6 50.9 52.2 52 52 51.8 51.2
TiO2 1.1 1.37 1.13 1.38 1.72 1.2 1.12 1.2 1.17 1.05
A12O3 14 13.8 14 14.9 15.3 14.3 14.3 14.2 14.1 13.5
Fe2O3 2.64 3.21 2.82 2.93 3.77 1.84 2.19 3.02 2.94 2.67
FeO 8 8.4 8 8.2 9 8.7 8.4 7.6 7.8 7.4
MnO 0.17 0.18 0.17 0.17 0.18 0.17 0.17 0.18 0.19 0.17
mgo 7.84 6.3 7.66 5.28 5.12 7.25 7.61 7.14 7.2 8.36
CaO 11.1 10.2 11.1 8.29 10.4 11 11 10.7 11 11.1
Na2O 1.98 2.28 2.05 4.23 2.61 2.17 2.08 2.13 1.95 2.35
K2O 0.54 0.77 0.49 1.1 0.59 0.59 0.59 0.72 0.52 0.4
P2O6 0.14 0.17 0.14 0.18 0.13 0.15 0.14 0.15 0.15 0.13
H2O+ 0.71 1 0.78 1.2 0.66 0.54 0.67 0.49 1.2 1.1
H2O- 0.18 0.19 0.2 0.31 0.22 0.21 0.19 0.43 0.59 0.3
CO2 <0.01 <0.01 <0.01 0.01 <0.01 <0.01 <0.01 0.02 0.01 <0.01
S 0.03 0.06 0.04 6.03 0.03 0.05 0.03 0.03 0.05 0.03
F 0.02 0.03 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02
Cl <0.00 0.01 0.05 0.01 0.01 <0.00 0.01 0 <0.00 0.01
? 100.44 99.96 100.55 99.84 100.66 100.4 100.51 100.04 100.7 99.78
Sc (ppm) 36 37 37 33 38 36 36 35 37 35
Cr 310 171 310 50 25 240 340 260 300 400
Co 47 46 47 41 51 45 47 45 47 48
Ni 90 68 92 47 53 80 96 83 89 110
Zn 67 79 69 81 86 71 67 73 71 67
Ga 19 20 19 22 22 20 20 20 20 18
As 1.5 <1.00 2 <1.10 <1.10 <1.10 <1.20 <1.2 <1.20 <1.20
Rb 21 31 22 49 23 23 22 28 18 18
Sr 180 190 190 320 230 200 190 210 190 230
Sb <0.140 0.16 0.25 0.14 <0.150 0.23 0.18 0.21 <0.150 <0.150
Cs 0.53 0.64 1.3 0.42 0.39 0.49 0.8 0.5 0.31 <0.220
Ba 150 180 170 240 180 160 140 180 150 140
Y 20 24 20 25 19 21 20 21 20 18
La 11 13.4 11 13.9 11 11 11 11 11 9.6
Ce 22.4 28.4 22 27 22 23.3 22 24 24 20
Nd 12 15 11 17 11 14 9.6 11 14 12
Sm 3.4 4.1 3.5 4.2 3.4 3.6 3.4 3.6 3.6 3.1
Eu 0.99 1.3 1.04 1.26 1.15 1.1 0.99 1.1 1.1 0.93
Tb 0.65 0.75 0.64 0.77 0.65 0.68 0.62 0.63 0.63 0.54
Yb 2.1 2.7 2.2 2.6 2.3 2.3 2.1 2.3 2.3 1.9
La 0.32 0.39 0.34 0.37 0.32 0.38 0.31 0.32 0.37 0.29
Hf 2.6 3.1 2.6 3.3 2.4 2.7 2.4 2.6 2.4 2.2
Nb 7 8.5 7.1 10 7.6 7 7.2 7 7.5 6.9
Ta 0.53 0.6 0.53 0.65 0.5 0.59 0.49 0.55 0.53 0.43
Th 2.lo 2.6 2.2 2.8 2.2 2.2 2.1 2.2 2.2 1.9
U 0.43 0.53 0.59 0.6 0.52 0.76 <0.50 <1 0.44 <0.60
Pd (ppb) - - - 15 - - - - 10 -
Pt - - - 7.3 - - - - 10 -
Rh - - - 0.8 - - - - 0.6 -
Ru - - - <0.05 - - - - <0.05 -
Ir - - - <0.05 - - - - <0.05 -
Au <5.0 <4.0 <7.0 <8.0 <5.0 <5.0 <15.0 <11.0 <5.0 <5.0