ALASKA DIVISION OF GEOLOGICAL & REPORT OF INVESTIGATIONS 2020-07 GEOPHYSICAL SURVEYS Twelker and others, 2020 SHEET 1 OF 1 http://doi.org/10.14509/30469
145° 45' 00" 145° 30' 00" 146° 00' 00" 63° 21' 58"
14 146° 15' 00" D' 40 39
52
60
S ELECTED Ar/ Ar GEOCHR ONOLOGY 146° 30' 00"
!
! ! ! KJa
! ! !
! ! ! ! 75
!!!! ! ! !
!! !!!!! !! ! !! 57 60 ! !
! 54 ! 28
! ! ! !!!!! !! ! 40 42 "
4 ! !! !! !!!!! ! !!! 63° 21' 58" 60 DZ4 Km s
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! !!!! ! !!! ! ! ! ! 71 KJp
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10 ! !! D
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! 60 21
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! ! T 66 20 E Label Sample No. Material Age Reference
! ! L D E Z ^ 6 ? ^
|
! A
V rcp? ^ um
C L jcs
12 ! 70
!! ! 80 R rcp ? ! ! !
! 50 62 Unit
! !! ! E U " 22 U1 ^ N
! g
! 50
!! DZ8 E
!! !! 50
! ! !!! A 27 Kg
! ! !!! T
!! ! !!!!! 26 68 A
! ! ! !!! K
!!!
! !!! F L
!
!!! 33 "
! !! !!!!!! 80 "
3 ! !! ^ 13 L ! ! U 65 ! ! !
! ! !! ! !! Km s rcp J . Benow itz, w ritten ! ! 30
! ! 20 ! I
6 ! ! ! Qv
! 30 ^ A
15
! ! 55 Psv 12 A1 1 85 15ET166 W h ole rock 0.990 ± 0.028 Ma
80
3 11 ! 45 * 50 F U10
!
!
m v
! ^ ^
5 !!
g ^ Pi com m un., 2018
um 5
! 45 rcp
70 60
13 25
50 40 K
20
F KJp
! 22
!
! 60
!
! KJp? 20 E * N:s
! 40
! ! 60 m v Pi A A2 ! W AITUFF W h ole rock 3.808 ± 0.054 Ma Allen, 2016
2 5 ! ! ! !!!! 25 43 ^ E
! ! !!!! 60 40 um
15 ! ! ! ! ! U !
! ! !
49
2 !
! ! 18 R
!! ! !
!!! 28 L
! ! 25
17 !! ! !! 42 " 40 Keg 65 !
! A3
C
T
! ! ! 45 KJp 35 13ET270 Biotite 124.6 ± 0.5 Ma Benow itz and oth ers, 2014
! ! DZ9 ^ ^
70 um
! 15 *
4
! ! Psv
!!!
!
! m v
! B 18 !!
!! !!! !!! !!!! 55 A7 ^ !
! ! 34 Y
! !
! ! 50 " um
! 80 ! 60
! R ?
!!!! Keg !
! ! !!! !! ! ^ A4
! !! ! D
!! 70 Psv 40 ^ ^ Pi 15DR 140 Hornblende 138.4 ± 0.8 Ma Benow itz and oth ers, 2017
!! !
!! 53
! !
! ! um g
! !!!! O 20 50 ! ! ! ! ! ! D 64 F28 ^ ! ! !
4 ! ! ! !!! " A 52 um
! DZ7 ! ! 71 U8 69
!!!!! ! 55
!! I
45 X
55 ? R U 50
! ! 63 146.6 ± 4.4 Ma Turner and S m ith , 1974;
! " 60
! ! ! S S
!
! T 55 Keg R
! I
!! 54 P F 44 M A5 !
! ! !! O A * 71AS T-42 Am ph ibole
! 65 ! !
!! ! 70
!! U m v?
!! !! ! ! ^ L F25 !
! 60 KJa 50
70 " um T :
Pl N
! ! N s (K-Ar) W ilson and oth ers, 2015
! ! !! 25 80
!!
! 60 44
! G 31
!!
30
!! 80 ^
! U 30 ! 68 KJa
U7 um ^ 50
^g? ! L " ! 85 g
!! ! C 70 A6 ! !
! 15 ^ F16 15ET134 Ca-am ph ibole 219.1 ± 7.4 Ma Benow itz and oth ers, 2017
! 35 ! Psv
! ! 55 H
!! ! KJa ^
! !
! !
! um 50
! DZ3 ! 57 ^
45
4 16 F um *
^ A fv* ! U 62
! um 50
!! ! 34 KJp? *g ^ 66 L ^ ^ Bittenbender and oth ers, !
1 !!! !! ! ! um T ^um g U um ^rcp
22 75 :
! ^ 55 !
85 um N s 45 39 A7 HB03-29 Hornblende 225.7 ± 2.0 Ma 30
F17
KJp 35 ^ 80
um ? 63 2007
Keg? ^ Pi
! D ^
! rcp 30 rcp
65 ^ ^
70
Psv rcp
146° 45' 00" Ke g? ^g
44 A8
^ ^
Keg g Keg? g ^ * * 13R N428A Biotite 225.8 ± 1.1 Ma Benow itz and oth ers, 2014
56 um m v g
51
^
g T Pi
^
N:s 58 um "
81
45 A4 S 55
U
A9 Bittenbender and oth ers,
84 25 U 60 ^g
KJa 62
75 " 35 ^ A9 AK25515 Biotite 228.3 ± 1.1 Ma
^ g
g R *
35
fv*
U Keg? H "
65
Keg? T 2007 66
75
D *
^ 88 60 ^ g K
g R n2
" 70 E
GEOPHY S ICAL S UR V EY S GEOLOGIC MAPS FIELD S TATIONS Keg? DZ2 A E
^
Pi
D ^ I *
u m ^ R
N ^ n2 fv*
g Y C
um
U9
70
32
! ^
um ^
1. V aldez Creek (Burns and oth ers, 2004) 1. Kline and oth ers, 1990 9, 10. R ose, 1966 Alaska Division of Geological & Geoph ysical S urveys 2013 stations n1
F3 50
^ F27
77 U 50 31 g ^ KJa ! Psv
2. Burns and oth ers, 2014 2. S m ith and oth ers, 1988 11. Clautice and oth ers, 1989 Alaska Division of Geological & Geoph ysical S urveys 2015 stations ^ 75 S ELECTED U-Pb ZIR CON GEOCHR ONOLGY Psv 48 50 Pl?
60 36
30 : 55
! ^g D N s 42
3. S outh ern Delta R iver (Burns and oth ers, 2003) 3. S m ith , 1981 12. Bond, 1976 S elected Bureau of Land Managem ent stations (Bittenbender and oth ers, 2007) 11 ^ Pi 40
^g Psv? 53 Map Map Sample
60
Pl
" 38 80
! 30 DZ1 ^ * U ? Psv fv*
4. S altus and S im m ons, 1997 4. S ilberling and oth ers, 1981 13. S tout, 1976 S am ples of Greene and oth ers (2008) 41 F23 * No. Unit No. Age Reference D 46 33 F26 m v ^n2 40 80
60 M 47 Pi Kg
5. Mooney, 2010 14. Nokleberg and oth ers, 2015 Pi U1 15ATW -51 102.4 ± 1.1 Ma W aldien and oth ers, 2020
F15 40 c F20
35
30
30 30 ^ ^n1 ^ C Keg
n1
g F18 Pi U2 15ET135 134.9 ± 2.1 Ma Holm -Denom a and oth ers, 2020
6. Eden, 2013 15. S m ith , T.E., unpublish ed Mount Hayes A-6
A
10
^ 40 g? F22 75
32 20 ^ D ^ L Pi U3 KJag 07CS R 08b 142.2 ± 1.7 Ma Mooney, 2010
7. W aldien, 2015 16. Bundtzen, 2013 ^ n1 42 g
35
n1 ^ 66 Pi 52 ^Psv Psv L H 50
Pl 53 70 O
40 55 45
U U KJa O U4 07CS R 22c 149.8 ± 1.7 Ma Mooney, 2010
8. W aldien and R oeske, 2017 17. S tevens, 1971 30
KJp
42 43 D
63 ^ M
Psv
60 Pl O 63° 15' 00"
Pl Pl Pcog
35 ^Psv O U5 13R N372A 268.1 ± 11.6 Ma Tw elker and O'S ullivan, 2016
T
147° 00' 00" ^ F 70
^
g I n2 D 40 79 15 F
65 S H A
H Pcmt 60 U
30 R 10 U6 13ET295 277.3 ± 11.8 Ma Tw elker and O'S ullivan, 2016 63° 15' 00" L Pl
50 ^g? ^ U T
Psv U 60 S
T *g
P i U7 15DR 129 301.8 ± 2.7 Ma Holm -Denom a and oth ers, 2020 ? 75 60
30
60 75 50 L 5 45
70 70 31 ^um
55 F21
^ 30 A Psv U8 *g 16CS R -17A 306.4 ± 3.2 Ma T. W aldien, w ritten com m un., 2018
" K F1 40 60 55
CORRELATION OF MAP UNITS 43 30 39
63 37 E
A1 5 *g
Km s
35 U9 16ATW -83 306.9 ± 2.6 Ma W aldien and oth ers, 2020
20
35 Pl
Qv
65 Keg 25
65
40 45 ^
28 g
*g
60 65
:Kgg T U10 17ATW -11 304.0 ± 3.5 Ma T. W aldien, w ritten com m un., 2018
53
35 F19 50 H 45
45 R 4
62 F2
61 U
:
N s?
78 ^ S
39 A3 g?
Pcog Keg N:s? 51 T
" 0
60 45 80 40 Pcm t
40 57
43 60 51
50 75 S ELECTED DETR ITAL ZIR CON GEOCHR ONOLOGY
80 * 45
Quaternary P cm
Qv "
60
45 U5 ^
Keg ls ^
n1 A2
^
N:s Intrusive Rocks 67 F8 g?
45
Neogene * 36 R "
P cs Map Map Sample Maximum
82 IC
42
53
60 Pcog [^n2] E H
75 ^ ^ A 45 Psv g? [^um] No. Unit No. depositional age Reference
80 R
Jurassic-Cretaceous M etasedim entary Rocks Paleogene 40 62 60
D *
:Kg :Kgg P cs 42
C'
S 45
45 O DZ1 N:s 16ATW -86 6 Ma W aldien and oth ers, 2020
47 E A R 87 45 N
30 H 30 52 60
S Pcm t H Kms Kc 80 IG H N:s
K U6 W DZ2 15ATW -06 30 Ma W aldien and oth ers, 2020 Kg 25 E KJp " 46 A E ^ Y 65 ? ^ g
R 73 75 75 n2
Cretaceous V C 61 DZ3 N:s 16ATW -77 60 Ma W aldien and oth ers, 2020 147° 15' 00" A *
L D E Z 35 DZ6 P cm v
" 70 * 8
Keg P cm 80 71 Kms DZ4 15ATW -29 88 Ma W aldien and oth ers, 2020 U
48
KJp KJc KJa 50 18 ^ 42 75 ^ g 75
KJag : 45 ^ n1 Kc
Kg 80 * n2 DZ5 08CPM101 86.4 Ma Mooney, 2010
60 P cm : 30 35 N s D
W rangellia T errane Jurassic E 20 KJa 65 O N DZ6 08CPM134 148.5 Ma Mooney, 2010
15 26
Z 25 A 30 70 M
: R F6 P KJa
Kg 26 H ^ls A I DZ7 16ATW -10 156 Ma W aldien and oth ers, 2020
22 T S Y 34
E ^ H E A T E R N KJa ls C L
58 I
^rcp ^n2 70 35 H N E [^um] N:s
^g ^um M etam orphic 55 S DZ8 KJp 15ATW -23 160 Ma W aldien and oth ers, 2020 DZ5 ^
^n1 n2
B' 70
Clearwater M etam orphic Rocks com plex of T riassic 40 20 U " 28 ^Psv [^um]
A 23 12 14 ^ KJp
60 g DZ9 15LF304B 160 Ma Holm -Denom a and oth ers, 2020 Gulkana River 31 63 N
45 25
" 50 D T
U4 28 Kc 10 E
^Psv Pi Pcog Pcmt 59 42
65 E ^um ?
Pl Perm ian 25 45 60 35 37 29
K 35 70 ^ P*cl P*cs P*cmv P*gs L n2 ^
78 n1
25 75 : [^n2]
35 Kg A 26 35 S ELECTED PALEONTOLOGICAL DATA
70 ^
*fv 66 30 30 um ?
45 T 55 F7
*g *
Pennsylvanian m v
*mv ^
U3 85 Psv D? 42
20 35 Map Map
Parautochthonous 40 KJag " U 30
65 64
26 ^ Fossils Age Ref.
45 g
22
41
North Am erica M ississippian 85 U? No. Unit 30 D
T 15
L
35 F5
30
U 60 35 ^n1 Pollen: Pinus, Betula, Monocots, Nap (indeterm inate),
F1 N:s
A
60 Pliocene 1
70 20 35 35 32
20 Keg?
F ^
^ 33
^ n1 22 g
19
S ph agnum , Picea, Taxodiaceae, Ericalse, Pseudotsuga
Psv 36
I
40 "
147° 30' 00"
50 F9 L 85
|jcs Devonian 17 48 ^ 24 n2
A 25 Pollen: Alnus, Picea, Pinaceae, Betula, indeterm inate Miocene and Pliocene
A5 N:s
45
70 ^ F2 N
^ n2 1 ^ n2 45 ^Psv
E m * ^ m onocots, indeterm inate dicots (?) KJa 36 g *
D 41 ^ m v
g
^ 37 N:s E N g F3 Alnus evidens, Metasequoia (?) sp. Oligocene 1
Z O ^ 34 ^ Psv
n1 50 ^n1
R ^n1 KJc A 24 F4
E ^ 30 Buchia rugosa Late J urassic 2
H ^n1? Psv? 22 ^ S ^n2 15 g ^g
A ? ^g ^g ^m
N ^g F5 Heterastridium Late Triassic 3
T 61 ^
E 30 55 g T
E
K ^ 21
g? 51 L ^ Late Triassic
A g ^ ^ls
g F6 S
T 20 ^ Monotis subcircularis and M. salinaria 4
^ 29 um
Psv? (Norian) 52 ^g U 50 50 34 F7 ^ls Tropites cf. T. kellyi and Halobia cf. H. superba Late Triassic 3
R
^ls
H F8 Pelecypods Halobia sp. cf. H. superba Late Triassic 1 40 ^ 42
n1 D T
Middle or Late 80 45 ^n1
55 ^n1 50 38 ^ F9 Pelecypods Daonella or Halobia 1 U g
^ ^g ^ Triassic
Psv g? 30
55 40 ^g
35 * 49 F24 26 ^Psv
m v F10 Conodonts Neospathodus cf. N. pakistanensis Early Triassic 3
D
25
40 40 E
F10
E 40
^
^Psv
g F11 15 R adiolarians Triassic 3
N 40
40 K
35 60 ^
A ^ * g
30 g m v Conodonts Hindeodus excavatus, Xaniognathus sp., Probably late Early F11
147° 45' 00" L ^um A 15 F12 Pl I 43 41 29 ^ 5
20 85 g Pl ^ L Neogondolella biteeri to early Late Perm ian
H n1
I 30
E G D
N 35 ^ F13 Pl
O ^ H g ^Psv 25 Conodonts Neogondolella gracilis, Neogondolella sp. latest Early Perm ian 5
Z
Psv 30 ^
n2 ^ AR Psv W U
E AY 25 Conodonts Neogondolella bisselli and Neogondolella m iddle to late Early
SH ^um ? Qv? 16 F14 Pl A ^ 65 5 45 um H TN idahoensis plexus Perm ian E * D E 55 m v? EN
A S ^Psv LK 56 L F15 Antiquatonia (possibly related to A. reticulata) Perm ian 6 A Pl 45 I 35 T : HI I
^ N s? ^Psv *m v GHW AY ^Psv
g *m v 24 F16 Brach iopods Arctitreta sp., Spiriferella sp., Neospirifer (?) sp. Perm ian 1 F A' 80 40 U
R ugose corals, Bothrophyllum sp. cf. B. pseudoconicum F17 *fv 55 D Perm ian 1 Dobrolyubova 70 ^n2 KJa Pl
^ R ugose corals Pseudobradyphyllum (?) sp. A., Bradyphyllum um ^Psv 50 68 45 KJc 80 72 ^Psv (?) sp. A., Bothrophyllum sp. A.; Brach iopods Spiriferella sp., [^n2?] C F18 Early Perm ian 1 79 Choristites sp., Reticulatia sp., Yakovlevia sp., 50 ^g 63° 01' 30" 39 63° 01' 30" 146° 15' 00"
31 ^n2 147° 15' 00" 147° 00' 00" 146° 45' 00" 146° 30' 00" D 146° 06' 00" * Kochiproductus (?) sp.; Fusulinids Pseudofusulinella (?) sp.
65 147° 18' 00" P gs ^um Pl ^ls* 25 ^Psv Brach iopods Chonetinella sp., Spiriferellina sp.; Bryozoans; 40 83 F19 Early Perm ian 7
80 Ech inoderm s
A8 [^n2?] " 80 R ugose corals Bothrophyllum pseudoconicum Dobrolyubova; 35 40 148° 00' 00" F4 35 64 63° 00' 00" Brach iopods Neospirifer sp., Choristites sp., Unispirifer (?) ^ 40 g ^ 63° 00' 00" 80 n2 63° 00' 00" 145° 30' 00" F20 ^Psv sp., Yakovlevia sp., Linoproductus sp., Calliprotonia (?) sp., Early Perm ian 1 :Kg KJc 145° 45' 00" ^g 63° 00' 00" 146° 06' 00" 146° 00' 00" Denticulophora (?) sp.; Fusulinids Pseudofusulinella sp., 56 ^Psv Eoparafusulina (?) sp. ^ n2 : ^Psv ^ N s? Corals Timania sp. cf. T. schmidti Stuckenberg, Durhamina
Psv
50 K ^Psv T E F21 alaskaensis n. sp., Sinopora nintoi; Fusulinids Early Perm ian 1 A E L N
N E E U E O T A R A Pseudofusulinella sp., Schwagerina sp.
: R A Kg N Z N E
N A N F 50 C O
^ ^ O E g g T E T R
Z Fusulinids Schwagerina mankomenensis; Brach iopods Z A Z
K E E A H ^
n2 E N L R : E E E S Kg F14 R D Anemonaria sp.; Bryozoans indeterm inate Acanth ocladid (?), A A
A K K H A B B' C L C' T
62 A A' T L L ^ E S
um E Pl A A F22 A
A Dyscritella (?) sp., Fenestella spp., indeterm inate Early Perm ian 1
34 H H 21 ^ V T g T S W 2000 S 2000 m eters 2000 2000 m eters 2000 2000 m eters 59 ^Psv ^n1 Fenestelloid, Polypora (?) spp., indeterm inate R h abdom esids KJc ^n2 ^um ^Psv ^n2 ^g ^g Kc (?), Rhombotrypella sp., Streblotrypa sp. ^g ^g? ^Psv ^n2?
^n1 ^ ^g ^n2 ^n2 N:s? ^Psv g ^Psv 1000 Pl KJc 1000 1000 ^n2 1000 1000 Kms 1000 Fusulinids Schwagerina sp. moffiti, heineri, callosa,
^ [^n2] Pl ^n2
g ^Psv ^n1 ^g? Pl ^g ^g KJa KJa KJp Pseudofusulinella sp., Eoparafusulina waddelli; Tabulate ^g ^n2 Pl ^ls? KJa F23 corals Sinopora sp.; R ugose corals Hapsiphyllid sp., Early Perm ian 1 Pl 0 ^g 0 - SEA LEV EL 0 0 - SEA LEV EL 0 ^g ^Psv 0 - SEA LEV EL ^g Pl ^n2
*fv ^um ^Psv Clisiophyllum sp.; Brach iopods Antiqutonia sp., Camerisma ^Psv ^g KJa ^m ^m ^n2 *mv ^n1 sp., Neospirifer, sp., Spiriferellina (?), Spirifella sp. -1000 Keg KJa -1000 -1000 *mv -1000 -1000 -1000 40 20 *mv :Kg F24 ^Psv ^Psv ^Psv Brach iopods Early Perm ian 3 *mv
^n1 ^
^n1 ^Psv
^ g *mv? :Kg F25 Brach iopods Waagenoconcha sp. and Neospirifer sp. Early Perm ian 1
n2 T ^Psv ^g 30 L ^g -2000 -2000 -2000 ^g -2000 -2000 -2000 61 *mv? *mv? ^n1 R ugose corals Bothrophyllum sp. cf. B. pseudoconicum U ^Psv? ^g ^g *mv ^Psv A ^Psv F26 Dobrolyubova, Carninia (?) sp.; Tabulate corals Michelinia Early Perm ian 1 ^g F
^ls* -3000 -3000 -3000 -3000 -3000 -3000 sp.; Indeterm inate brach iopods F13 43 No vertical exaggeration No vertical exaggeration No vertical exaggeration 49 Pl *fv Middle Pl F27 Fusulinids Fusulinella sp. 1 84 Pennsylvanian ^ n1 ^n1 66 R ugose corals Cryptophyllum striatum; Tabulate corals A *fv T ^ N ^ T Cladochonus sp., Michelinia sp.; Brach iopods Linoproductus Early to Middle L n2 70 n2 L F28 *mv 1
U U
A
A sp., Juresania sp., Stenocisma sp., Institina(?) sp., Pennsylvanian N 58 A H
F T F O
C Z
S Chaoiella(?) sp.; Ceph alopods Pseudoparalegoceras hansoni H ^ ^ K L
A n2 n2 E T X E * C U D
m v L 1 2 3 L E W O
L Nokleberg and oth ers, 1992; S m ith and oth ers, 1988; S ilberling and oth ers, 1981; G U
U R R
? A A
17 80 N 4 5 6 7 B G V C F Clautice and oth ers, 1989; Kline and oth ers, 1990; R ose, 1965; Blodgett, 2002
O
BRO XSO N GU LCH FAU LT I S ^ D D' E L E' n1 80 (projected from west) T X ^ KJp A Psv *mv *fv L CONTACTS Ages are those ascribed by the source reports and have not been reinterpreted KJp N 80 O 45 ^n2* ^g ^rcp *mv U
2000 2000 m eters 2000 E
AM PHIT HEAT ER SY NCLINE R ^g ^Psv Pi Pi *mv *fv A
Pi D B F ^g 50 ^n1 N:s Kms Pi *mv ^g F12 35 ^Psv CONTACT - Identity and existence certain, location accurate ^ ^n1 ^um ^um
g? 1000 Pl 1000 1000 *mv 1000 m eters
^ g ^n1 ^g
^n2 ^Psv N:s ^Psv ^Psv ^ ^g ^n1 ^rcp A *g R EFER ENCES CITED ^ n2? ? 53 n1 ? ^n2 KJa CONTACT - Identity and existence certain, location approxim ate ^n1 I
Pl * A6 Keg ^n1 Pl R M c C
fv S A L ^g " 0 P*gs ^Psv ^ g ^g ^Psv Pl 0 - SEA LEV EL 0 ^n1 L U M 0 - SEA LEV EL U2 ^n1 ? ^n1 T ^Psv HO O DO O FAU LT ? T H |jcs ^n2 Pl " ^Psv ^g ^Psv R R U S
^um ^um I ^Psv T CONTACT - Identity and existence certain, location inferred Allen, W.K., 2016, Miocene-Pliocene strike-slip basin developm ent along th e Denali fault system in th e eastern Alaska R ange:
45 F ^Psv P *g *mv
^g? I ? ^Psv ^Psv Ch ronostratigraph y and provenance of th e McCallum form ation and im plications for displacem ent: W est Lafayette, Indiana, S Pl?
B -1000 H F -1000 -1000 -1000
*mv ^g ^Psv Pl A ^Psv Purdue University, M.S . th esis, 146 p. L ^Psv R U *fv A T
A A L CONTACT - Identity or existence questionable, location inferred
I ? 22 T ^Psv 68 65 35 K E ^Psv *fv? N Y Beard, J.S., and Barker, Fred, 1989, Petrology and tectonic significance of gabbros, tonalites, sh osh onites, and anorth osites
20 ^g ^n2 C *mv
-2000 T ^um R -2000 -2000 -2000 ^Psv H E in a Late Paleozoic arc-root com plex in th e W rangellia terrane, south ern Alaska: J ournal of Geology, v. 97, n. 6, p. 667–683.
35 R E K U S ^n1 *fv? *mv? CONTACT - Identity and existence certain, location concealed 60 A T *fv? T H 40 39 62° 50' 24" Pl ^n2 ^Psv R U Benowitz, J.A., Layer, P.W., and Twelker, Evan, 2014, Ar/ Ar data from rocks collected in 2013 in th e W rangellia m ineral ^Psv Pl S T 148° 00' 00" 62° 50' 24" -3000 -3000 -3000 -3000 assessm ent area, Gulkana, Healy, Mount Hayes, and Talkeetna Mountains quadrangles, Alaska: Alaska Division of Geological 147° 45' 00" 147° 30' 00" 147° 18' 00" No vertical exaggeration No vertical exaggeration INTER NAL CONTACT - Form lines to bedding and volcanic layering & Geoph ysical S urveys R aw Data File 2014-18, 10 p. h ttp://doi.org/10.14509/29119 Benowitz, J.A., Layer, P.W., Wypych, Alicja, and Twelker, Evan, 2017, 40Ar/39Ar data from rocks collected in th e 2015 FAULTS AND FOLDS W rangellia m ineral assessm ent project area, Mount Hayes A-5, Mount Hayes B-6, and Talkeetna Mountains D-2 quadrangles, Alaska: Alaska Division of Geological & Geoph ysical S urveys R aw Data File 2017-1, 9 p. h ttp://doi.org/10.14509/29699 FAULT - Identity and existence certain, location accurate Bittenbender, P.E., Bean, K.B., Kurtak, J.M., and Deininger, James, 2007, Mineral assessm ent of th e Delta R iver Mining District area, east-central Alaska: U.S . Bureau of Land Managem ent Alaska Tech nical R eport 57, 697 p. FAULT - Identity and existence certain, location approxim ate Blodgett, R.B., 2002, Paleontological inventory of th e Am ph ith eater Mountains, Mt. Hayes A-4 and A-5 quadrangles, R AINY CR EEK PICR ITE (LATE TR IAS S IC)— Black, aph anitic, m assive to GR ANITIC R OCKS (LATE PENNS Y LV ANIAN)— Pluton and sm aller stocks of MAR BLE (PENNS Y LV ANIAN TO PER MIAN)— Lam inated to m assive m arble and Kg GR ANITIC R OCKS (MIDDLE CR ETACEOUS )— S m all intrusions of h ornblende KJa AR GILLITE (LATE J UR AS S IC TO EAR LY CR ETACEOUS )— Argillite, slate, ^rcp *g P*cm south central Alaska: Alaska Division of Geological & Geoph ysical S urveys R eport of Investigation 2002-3, 11 p. INTR ODUCTION fragm ental picrite volcanic rocks and related h ypabyssal dikes. May h ave originated m edium - to coarse-grained quartz m onzonite, granodiorite, granite, and quartz diorite. argillaceous m arble. Locally carbonaceous. Form s tw o m appable layers and num erous quartz m onzonite, diorite, and granodiorite; m ay grade into pyroxene- and olivine- m etaw acke, and m eta-andesite. Fine-grained m etasedim ents contain local FAULT - Identity and existence certain, location inferred h ttp://doi.org/10.14509/2858 Th is m ap presents interpreted bedrock geology for a portion of th e north eastern cum ulate ph ases. Exh ibits a w eakly to m oderately developed m agm atic-em placem ent m etagreyw acke interbeds. Average grain size is 0.01–0.05 m m . Ch aracterized by a as pyroclastic rocks, subm arine volcaniclastic rocks, or flow breccia. In th in section, Th is unit is ch aracteristically altered, resulting in near-total replacem ent of biotite sm aller interlayers w ith in adjacent units. Metam orph osed to greensch ist facies. Age Bond, G.C., 1976, Geology of th e R ainbow Mountain - Gulkana Glacier area, eastern Alaska R ange, w ith em ph asis on upper th e rock is aph anitic, lacking olivine ph enocrysts or serpentinite pseudom orph s after and h ornblende by ch lorite, epidote, and iron oxides; plagioclase is altered to sericite, is likely Perm ian based on th e conform ably(?) overlying m etavolcaniclastic rocks of Paleozoic strata: Alaska Division of Geological & Geoph ysical S urveys Geologic R eport 45, 47 p., 3 sh eets. Talkeetna Mountains and th e eastern Alaska R ange th at is prim arily underlain by fabric defined by aligned am ph iboles and plagioclase. Th e quartz com m only h as w ell-developed planar fabric and m etam orph osed to low er greensch ist facies; ? FAULT - Identity and existence questionable, location inferred Pennsylvanian th rough Triassic rocks of th e W rangellia terrane, plus structurally undulose extinction and exh ibits sh ear bands. Th e low er contact is strongly altered to diagnostic m etam orph ic m inerals are graph ite, ch lorite, clinozoisite, and w h ite m ica. olivine. Th e dom inant identifiable m ineral is fine-grained secondary actinolite, w h ich epidote, and clay m inerals. Microcline is m uch less altered, but quartz is strained Perm ian age (unit Pcmt). h ttp://doi.org/10.14509/373 em placed J urassic th rough Cretaceous m etasedim entary rocks th at form ed north and secondary calcite in th e im m ediate vicinity of th e Broxson Gulch fault. Zircons from Detrital zircon spectra from th is unit (m ap location DZ6, Mooney, 2010; m ap location can account for up to 95 percent of som e sam ples and is consistent w ith m etam orph ism (S tout, 1976). U-Pb zircon ages range from 301.1 ± 2.7 to 306 ± 1.6 Ma (see selected U- Bundtzen, T.K., 2013, Estim ation of R esource Potential, Lich en Copper-S ilver-Gold Prospect, V aldez Creek Mining District, MAFIC METAV OLCANIC R OCKS (PENNS Y LV ANIAN TO PER MIAN)— Dark green- FAULT - Identity and existence certain, location concealed th th east of W rangellia prior to its accretion to North Am erica. It provides th e geologic th is intrusion yield a m agm atic age of 102.19 ± 0.77 Ma (m ap location U1; W aldien and DZ7, W aldien and oth ers, 2020) are dom inated by a Late J urassic population sim ilar at low er greensch ist facies. Picrite volcanic rocks overlie units ^Psv and ^um on an Pb zircon geoch ronology table). P*cmv S outh -Central Alaska, May 15 , 2009; updated J anuary 28 , 2013: National Instrum ent 43-101 Tech nical R eport prepared for gray and red-brow n basaltic agglom erate and pillow ed m etabasalt, w ith local andesite Alaska V entures, Inc., 103 p. fram ew ork for know n and potential m ineral resources related to th e geology of oth ers, 2020). to th at found in th e structurally adjacent unit KJp. apparent angular unconform ity, and clasts of dunite appear locally in picrite 40 39 FELS IC V OLCANIC R OCKS (PENNS Y LV ANIAN)— Predom inantly felsic volcanic and gabbroic rocks. V olcanic rocks are interlayered w ith local th in layers of ch ert and ? FAULT - Identity or existence questionable, location concealed W rangellia, including m agm atic nickel-copper-cobalt-platinum group elem ent deposits intrusions. Ar/ Ar analysis of h ornblende from th is unit yielded an age of 225.7 ± 2 *fv Burns, L.E., U.S. Bureau of Land Management, Fugro Airborne Surveys, and Stevens Exploration Management GR ANITIC R OCKS (EAR LY CR ETACEOUS )— W idely scattered stocks and plutons of CONGLOMER ATIC S EDIMENTAR Y R OCKS (LATE J UR AS S IC TO EAR LY rocks, including volcaniclastic rocks of dacitic to rh yolitic com position, plus lesser flow s siliceous, argillaceous lim estone. Metam orph osed to greensch ist facies. Th e only age Corp., 2003, Plot files of th e airborne geoph ysical survey data of th e south ern Delta R iver area, east-central Alaska: Alaska h osted by Late Triassic m afic and ultram afic intrusions, copper-silver deposits related Keg KJc Ma (m ap location A7; Bittenbender and oth ers, 2007), in agreem ent w ith oth er ages fine- to m edium -grained granodiorite, granite, diorite, and m onzonite. Th e largest of CR ETACEOUS )— Interbedded sh ale, siltstone, sandstone, lith ic w acke, and polym ictic of rh yolite to dacite com position. A few th in interbeds of argillaceous siltstone, control for th is unit is from interlayered lim estone, w h ich includes conodonts of post- THR US T FAULT - Identity and existence certain, location accurate Division of Geological & Geoph ysical S urveys Geoph ysical R eport 2003-5, 1 DV D. h ttp://doi.org/10.14509/2904 to m etam orph ism of th e Late Triassic Nikolai Greenstone, and copper-gold skarn for Nikolai Greenstone m agm atism . Trace-elem ent geoch em istry indicates th at unit th ese plutons h as a U-Pb zircon age of 134.9 ± 2.1 Ma (m ap location U2; Holm -Denom a conglom erate. Exh ibits num erous graded, fining-upw ard sequences. Conglom erate claystone, calcareous sandstone, m arble, and dolom itic m arble are also present. Middle Devonian age (Clautice and oth ers, 1989). Th e com position and style of th is Burns, L.E., Fugro Airborne Surveys Corp., and Stevens Exploration Management Corp., 2004, Line, gridded, and deposits associated w ith Early Cretaceous plutonism . ^rcp is th e ch em ically prim itive relative of th e h igh -Ti upper m em ber of th e Nikolai vector data, and selected plot files of th e airborne geoph ysical survey data of th e V aldez Creek m ining district, central Alaska: and oth ers, 2020). 40Ar/39Ar dating of h ornblende returned an age of 138.4 ± 0.8 Ma for contains subrounded to w ell-rounded, granule- to sm all-boulder-sized clasts of basalt, ^n2 Metam orph osed to low er greensch ist facies. Fossils from th is unit indicate a Middle unit, including th e interlayered sedim entary rocks and th e stratigraph ically THR US T FAULT - Identity and existence certain, location approxim ate Greenstone (unit ). Alaska Division of Geological & Geoph ysical S urveys Geoph ysical R eport 2004-3, 1 DV D. h ttp://doi.org/10.14509/3337 Th is m ap synth esizes and reinterprets m ultiple generations of geologic m aps, a granodiorite stock in th e Maclaren R iver drainage (m ap location A4; Benow itz and andesite, diabase, greyw acke, and siliceous argillite in a m atrix of calcareous Pennsylvanian age (Bond, 1976); th e top of th e unit is interpreted to be th e boundary overlying(?) m etavolcaniclastic rocks of Perm ian age (unit Pcmt), is m ost closely Burns, L.E., CGG, and Fugro GeoServices, Inc., 2014, W rangellia survey area: Airborne m agnetic and electrom agnetic data geoph ysical surveys, geoch em istry, and geoch ronology, plus incorporates targeted field oth ers, 2017), w h ile 40Ar/39Ar biotite yielded an age of 124.6 ± 0.5 Ma for m onzonite 10 greyw acke. An argillite bed w ith in th is unit (m ap location F4) contains an assem blage GABBR O (LATE TR IAS S IC)— S ill-form intrusions of fine- to m edium -grained, dark betw een Pennsylvanian and Perm ian strata (S tout, 1976). sim ilar to th at of th e Pennsylvanian m afic volcanic rocks of th e W rangellia terrane ? THR US T FAULT - Identity and existence questionable, location approxim ate ^g in line (point), grid, vector, and m ap form ats, Talkeetna Mountains, Healy, and Mt. Hayes quadrangles, south -central Alaska: observations by geologists from th e Alaska Division of Geological & Geoph ysical km to th e south w est (m ap location A3; Benow itz and oth ers, 2014). Gneissose texture of Late J urassic fossils, including pelecypods Buchia rugosa (S m ith and oth ers, 1988). greenish -gray gabbro, h ornblende gabbro, olivine gabbro, and diorite. Prim ary (unit *mv). *mv MAFIC V OLCANIC R OCKS (PENNS Y LV ANIAN)— Flow s, volcanic breccias, and Alaska Division of AGeological & Geoph ysical S urveys Geoph ysical R eport 2014-1, 56 sh eets, scale 1:63,360, 1 DV D. S urveys, th e University of Alaska, and th e University of California, Davis. Additional occurs locally. Metam orph osed at low er greensch ist facies (Nokleberg and oth ers, m inerals are clinopyroxene and plagioclase, plus local h ornblende, biotite, quartz, THR US T FAULT - Identity and existence certain, location inferred volcaniclastic rocks prim arily of andesitic, basaltic, and locally dacitic com position. h ttp://doi.org/10.14509/27022 discussion of th e geology and m ineral potential of th e m ap area is presented in a 2015). PENNS Y LV ANIAN-TR IAS S IC IGNEOUS AND S EDIMENTAR Y m agnetite, and olivine. Metam orph osed to low er greensch ist facies. 40Ar/39Ar dating of Interbedded w ith volcanically derived lith ic sandstone, greyw acke, calcareous Clautice, K.H., Smith, T.E., Pessel, G.H., and Solie, D.N., 1989, Geology and m ineral occurrences, upper Clearw ater Creek com panion report, Tw elker and oth ers (2020). biotite from olivine gabbro in th e Butte Creek area yielded a Late Triassic age of 225.8 ? THR US T FAULT - Identity and existence questionable, location inferred UNITS (W R ANGELLIA TER R ANE) sandstone, and lim estone. Metam orph osed to low er greensch ist facies. Unit is overlain METAMOR PHIC COMPLEX OF GULKANA R IV ER area, Mt. Hayes A-6 Q uadrangle, Alaska: Alaska Division of Geological & Geoph ysical S urveys Public Data File 89-18, 14 p., 2 KJag ALKALI GABBR O (LATE J UR AS S IC TO EAR LY CR ETACEOUS )— A single, 5- ± 1.1 Ma (m ap location A9; Benow itz and oth ers, 2014). Unit ^g gabbro sills represent *fv, sh eets, scale 1:24,000. h ttp://doi.org/10.14509/1421 square-km stock of lith ologically h eterogeneous coarse-grained, neph eline-bearing ^m MÉLANGE (TR IAS S IC)— Tectonic m ixture of fine-grained m etavolcanic and ^n1 ^n2 by felsic volcanic rocks of unit and on th is basis is interpreted to be of (W R ANGELLIA TER R ANE?) com agm atic intrusive equivalents of th e Nikolai Greenstone (units and ) and THR US T FAULT - Identity and existence certain, location concealed Dusel-Bacon, Cynthia, Hopkins, M.J., Mortensen, J.K., Dashevsky, S.S., Bressler, J.R., and Day, W.C., 2006, gabbroic rocks dom inated by h ornblende m onzogabbro; less abundant ph ases include m etasedim entary rocks, including ch lorite sch ist, th in (less th an 1 m -th ick) layers of Pennsylvanian age. sh are th e sam e geoch em ical ch aracteristics, including bim odal Ti concentrations, but P*gs GR EENS CHIS T (PENNS Y LV ANIAN TO PER MIAN)— Metam orph osed m afic rocks of Paleozoic tectonic and m etallogenic evolution of th e pericratonic rocks of east-central Alaska and adjacent Y ukon, in Colpron, th eralite, m onzonite, and m onzodiorite (S m ith , 1981). Alkali gabbro from th e stock foliated gray m arble, calcareous m etasedim entary rocks, volcaniclastic rocks, greenish Maurice, and Nelson J .L., eds., Paleozoic Evolution and Metallogeny of Pericratonic Terranes at th e Ancient Pacific Margin of EX PLANATION OF MAP UNITS are not differentiated at th is m ap scale. basaltic to andesitic com position. Hornblende ph enocrysts and volcaniclastic textures OV ER TUR NED THR US T FAULT - Identity and existence certain, location accurate yielded a U-Pb zircon age of 142.2 ± 1.7 Ma (m ap location U3; Mooney, 2010). Th e stock ph yllite, carbonaceous argillite, and ch ert. Metam orph osed to greensch ist facies. Fossil North Am erica, Canadian and Alaskan Cordillera: Geological Association of Canada, S pecial Paper 45, p. 25–74. are preserved locally. In th e m ap area, th ese rocks h ave been m etam orph osed to ULTR AMAFIC R OCKS (LATE TR IAS S IC)— S ill-form intrusions of olivine ± CENOZOIC S EDIMENTAR Y AND V OLCANIC UNITS h as been m etam orph osed to preh nite-pum pellyite facies (S m ith , 1981). evidence, including th e h ydrozoan Heterastridium (m ap location F5; S ilberling and ^um Eden, K., 2013, S tellar Property, V aldez Creek Mining District, S outh -Central Alaska: National Instrum ent 43-101 Tech nical PALEOZOIC METAMOR PHIC UNITS OF THE CLEAR W ATER greensch ist facies. Th ese rocks are part of th e regional S trelna m etam orph ic com plex, OV ER TUR NED THR US T FAULT - Identity and existence certain, location inferred oth ers, 1981), indicates a Late Triassic (late Norian) age for at least part of th is unit. clinopyroxene cum ulate rocks, m ainly dunite, w eh rlite, troctolite, plagioclase R eport prepared for Millrock R esources, Inc., 100 p. (posted on w w w .sedar.com , J anuary 8, 2013). V OLCANIC FLOW S (Q UATER NAR Y )— Aph anitic, m edium -gray olivine-ph yric basalt MOUNTAINS (W R ANGELLIA TER R ANE?) w h ich is th ough t to represent th e m etam orph osed equivalent of Paleozoic W rangellia Qv J UR AS S IC-CR ETACEOUS METAS EDIMENTAR Y UNITS peridotite, and olivine gabbro. Intrusions are typically fine to m edium grained, and Greene, A.R., Scoates, J.S., and Weis, Dominique, 2008, W rangellia flood basalts in Alaska— A record of plum e–lith osph ere flow s unconform ably overlie late Paleozoic to Triassic bedrock and form tw o subtle LIMES TONE AND S HALE (LATE TR IAS S IC)— Th in- to m edium -bedded to m assive, stratigraph y (W ilson and oth ers, 2015; units ^Psv, *fv, *mv of th is m ap). ANTIFOR M - Identity and existence certain, location approxim ate ^ls m ineralogy includes olivine, poikilitic clinopyroxene, plagioclase, ch rom ite, and OR THOGNEIS S (PER MIAN)— Medium - to coarse-grained orth ogneiss of granite, interaction in a Late Triassic accreted oceanic plateau: Geoch em istry, Geoph ysics, Geosystem s, v. 9, n. 12, topograph ic h igh s, subsequently m odified by glaciation. 40Ar/39Ar dating of w h ole rock Kms MACLAR EN S CHIS T (LATE CR ETACEOUS )— Q uartz-m ica sch ist, plus lesser ligh t- to dark-gray, fine-grained lim estone. Interbedded or as lenses (tens of m eters Pcog h ornblende. Metam orph osed to low er greensch ist facies; olivine is partially to quartz m onzonite, quartz diorite, and granodiorite com position. Metam orph osed to h ttp://doi.org/10.1029/2008GC002092 indicates an age of 0.990 ± 0.028 Ma (m ap location A1; J .A. Benow itz, University of interlayered calc-sch ist and am ph ibolite. Q uartz-m ica sch ist is generally fine grained th ick and kilom eters long) w ith in black sh ale, siltstone, and volcaniclastic sedim entary S Y NFOR M - Identity and existence certain, location approxim ate com pletely serpentinized. Th e larger intrusions are m ultiph ase sill com plexes and are greensch ist facies. Zircons from th is unit yield a Perm ian (268.1 ± 11.6 Ma) U-Pb Greene, A.R., Scoates, J.S., and Weis, D., Katvala, E.C., Israel, Steve, and Nixon, G.T., 2010, Th e arch itecture of oceanic Alaska, Fairbanks, w ritten com m un., 2017). (approxim ately 0.1–0.3 m m ) and consists of quartz and a penetrative foliation defined rock. Macrofossils including Monotis subcircularis, M. salinaria (m ap location F6; com agm atic to both ^n1 and ^n2 (Lande, 2016). m agm atic crystallization age (m ap location U5; Tw elker and O'S ullivan, 2016). Older PAR AUTOCHTHONOUS NOR TH AMER ICA plateaus revealed by th e volcanic stratigraph y of th e accreted W rangellia oceanic plateau: Geosph ere, v. 6, n. 1, p. 47–73. by w h ite m ica, biotite, ch lorite, and graph ite. Accessory m inerals include Clautice and oth ers, 1989), Topites cf. T. kellyi, and Halobia cf. H. superba (m ap S EDIMENTAR Y R OCKS (PALEOGENE TO NEOGENE)— Mixed unit including grains w ith ages betw een 285 and 308 Ma m ay be inh erited from earlier ph ases of th e MEAS UR ED PLANES Holm-Denoma, C.S., Sicard, K.R., and Twelker, Evan, 2020, U-Pb geoch ronology of igneous and detrital zircon sam ples N:s porph yroblasts of garnet and calcic plagioclase, calcite, epidote-clinozoisite, location F7; S ilberling and oth ers, 1981) indicate a Late Triassic age. Th is unit overlies Pi HY PABY S S AL INTR US IONS (PER MIAN)— Hypabyssal dikes, sills, and stocks of |jcs J AR V IS CR EEK S CHIS T (DEV ONIAN AND OLDER )— Intensely deform ed from th e Tok R iver area, eastern Alaska R ange, and Talkeetna Mountains, Alaska: Alaska Division of Geological & Geoph ysical poorly to m oderately indurated, clast-supported, fine-grained to pebble sandstone, S kolai arc (290–320 Ma; Beard and Barker, 1989). Th is inh eritance, as w ell as th e lack h ornblende, staurolite, and local kyanite and sillim anite. Detrital quartz and th e Nikolai Greenstone (unit ^n2). andesite porph yry, plus lesser dacite porph yry and rh yolite. Th is unit intrudes th e m etasedim entary rocks including quartz-m ica sch ist, quartzite, ch lorite-w h ite m ica INCLINED BEDDING S urveys R aw Data File 2020-3, 20 p. h ttp://doi.org/10.14509/30439 of any Precam brian inh eritance, suggests th e Clearw ater terrane m ay be 40 siltstone, sparse th in coal layers, and conglom erate containing sparse sand lenses. As plagioclase grains are rare. Protolith s are pelitic sedim ents, sandstone, and greyw acke Early Perm ian to Middle Pennsylvanian S lana S pur Form ation (part of unit ^Psv) and sch ist, quartz-biotite sch ist, calc-sch ist, and m arble. Metam orph osed to low er- m etam orph osed equivalents of th e W rangellia terrane. Th is unit m ay be tem porally Kline, J.T., Bundtzen, T.K., and Smith, T.E., 1990, Prelim inary bedrock geologic m ap of th e Talkeetna Mountains D-2 m apped, th e unit com prises m ultiple successive sedim entary units as young as w ith m inor m arl, andesite, and gabbro (Nokleberg and oth ers, 2015). Metam orph osed ^n2 NIKOLAI GR EENS TONE, UPPER MEMBER (LATE TR IAS S IC)— Dark gray-green is interpreted as com agm atic w ith volcanic rocks interbedded w ith in th at unit greensch ist to low er-am ph ibolite facies. Th is unit is part of th e J arvis Belt of Q uadrangle, Alaska: Alaska Division of Geological & Geoph ysical S urveys Public Data File 90-24, 13 p., 1 sh eet, scale 1:63,360. equivalent to th e early to m iddle Perm ian h ypabyssal intrusions in th e R ainbow R idge V ER TICAL BEDDING Pliocene and possibly as old as Paleocene (m ap location DZ3; W aldien and oth ers, to am ph ibolite facies. Th e m axim um depositional age, based on detrital zircons, is Late to m aroon, m assive, am ygdaloidal m etabasalt flow s and flow breccia. Flow s are th in (Nokleberg and oth ers, 2015). Th is unit m ay correlate to m iddle Perm ian orth ogneiss m etam orph osed parautoch th onous continental m argin rocks of Interior Alaska (Dusel- h ttp://doi.org/10.14509/1458 2020). Interbedded volcanic rocks are as young as 3.808 ± 0.054 Ma (40Ar/39Ar dating to th ick, locally colum nar, and generally interpreted as subaerial. Metam orph osed to Pcog area (unit Pi). Cretaceous (m ap location DZ4; W aldien and oth ers, 2020). (unit ) of th e Clearw ater terrane. Bacon and oth ers, 2006). OV ER TUR NED BEDDING Lande, L.L., 2016, A petrological m odel for em placem ent of th e ultram afic Ni-Cu-PGE alph a com plex, eastern Alaska R ange: of interbedded teph ra; m ap location A2; Allen, 2016) and as old as 31.1 Ma (K-Ar, low er greensch ist facies. Locally porph yritic, w ith plagioclase ph enocrysts up to 7 m m . 65 METAS EDIMENTAR Y R OCKS (PENNS Y LV ANIAN TO PER MIAN)— A m ixed Fairbanks, Alaska, University of Alaska Fairbanks, M.S . th esis, 144 p. h ornblende in tuff; Nokleberg and oth ers, 1992). Plant fossils and pollen indicate ages Kc CONGLOMER ATE (LATE CR ETACEOUS )— A single, fault-bound w edge of pebble to For th e purposes of th is m ap, th e Nikolai Greenstone is subdivided into h igh and low LIMES TONE (PER MIAN)— Ligh t- to m edium -gray bioclastic lim estone, calcarenite, P*cs Pl m etasedim entary and m etavolcanic assem blage including dark-gray to black fissile Mooney, P.R., 2010, Geology of th e Clearw ater Mountains and th e S outh ern Boundary of th e Alaska R ange S uture Zone: 20 INCLINED CLEAV AGE spanning from late Eocene to Pliocene (m ap locations F1–F3 ; Nokleberg and oth ers, boulder conglom erate w ith a m atrix of poorly sorted, fine-grained lith ic sandstone. TiO2 subgroups follow ing th e criteria of Greene and oth ers (2008); greenstones of unit im pure m arble, and dolom itic m arble. Locally interlayered w ith volcaniclastic University of California, Davis, M.S . th esis, 93 p. W ell-rounded, h em atite-coated clasts include basalt, diorite, and greyw acke. Th e unit argillite, gray-green to apple-green sch istose m etavolcaniclastic rocks, and tabular- 1992). ^n2 h ave TiO2 greater th an about 1.4 percent. Unit ^n2 postdates and sedim ents. Metam orph osed to low er greensch ist facies. Ch aracterized by abundant ACKNOW LEDGMENTS bedded m etagrayw acke of volcaniclastic provenance. Metam orph osed to greensch ist INCLINED METAMOR PHIC OR TECTONIC FOLIATION Nokleberg, W.J., Aleinikoff, J.N., Dutro, J.T., Jr., Lanphere, M.A., Silberling, N.J., Silva, S.R., Smith, T.E., and h as undergone regional m etam orph ism to preh nite-pum pellyite facies. Detrital zircons stratigraph ically overlies unit ^n1 (w h ere present). A com bination of radiom etric ages, m acro- and m icrofossils, including brach iopods and corals of Late Perm ian age (m ap 35 Turner, D.L., 1992, Map, tables, and sum m ary of fossil and isotopic age data, Mount Hayes Q uadrangle, eastern Alaska R ange, facies. Age is likely Perm ian based on th e presence of conform able layers of Perm ian Th is project w as funded by th e Alaska Legislature as part of th e S tate of Alaska’s J UR AS S IC-PALEOGENE INTR US IV E UNITS from th e conglom erate range from Late Cretaceous to Arch ean in age; th e m axim um paleontological data, and m agnetostratigraph ic constraints indicate th at th e entirety locations F15 [R ose, 1965], F22, F23 [Nokleberg and oth ers, 1992]). Conodonts from Alaska: U.S . Geological S urvey Miscellaneous Field S tudies Map 1996-D, 43 p., 1 sh eet, scale 1:250,000. m etavolcaniclastic rocks (unit Pcmt) w ith in th e unit. S trategic and Critical Minerals Assessm ent project, part of th e Division of Geological V ER TICAL METAMOR PHIC OR TECTONIC FOLIATION depositional age based on th e youngest population is approxim ately 86 Ma (m ap of th e approxim ately 3500-m -th ick Nikolai Greenstone (^n1 and ^n2) erupted during th is unit in th e Talkeetna Mountains D-2 Q uadrangle are also of Early Perm ian age Nokleberg, W.J., Aleinikoff, J.N., Bond, G.C., Ferrians, O.J., Jr., Herzon, P.L., Lange, I.M., Miyaoka, R.T., Richter, GR ANITIC R OCKS (CR ETACEOUS TO PALEOGENE)— S m all stocks and plugs of & Geoph ysical S urvey’s Airborne Geoph ysical/Geological Mineral Inventory (AGGMI) :Kg location DZ5; Mooney, 2010). (m ap locations F12, F13; Kline and oth ers, 1990). D.H., Schwab, C.E., Silva, S.R., Smith, T.E., and Zehner, R.E., 2015, Geologic m aps of th e eastern Alaska R ange, Alaska a sh ort tim e period around 230 to 225 Ma (Greene and oth ers, 2010). Pcmt METAV OLCANICLAS TIC R OCKS (PER MIAN)— Ligh t-green to gray-green ph yllitic fine- to m edium -grained, equigranular to porph yritic granitic rocks, m ainly of program . Mapping and geoch ronology by Trevor S . W aldien w as supported by U.S . INCLINED CUMULATE FOLIATION (44 quadrangles, 1:63,360 scale), w ith descriptions and interpretations of m ap units: Alaska Division of Geological & Geoph ysical m etavolcaniclastic rocks w ith subordinate ch lorite-quartz-plagioclase m etavolcani- 45 interm ediate com position. S ubordinate lith ologies range from gabbro to felsite. In th e KJp PHY LLITE (LATE J UR AS S IC TO EAR LY CR ETACEOUS )— W h ite m ica-quartz S EDIMENTAR Y AND V OLCANIC R OCKS (PER MIAN TO TR IAS S IC)— A m ixed unit Geological S urvey Aw ard No. G16AC00206. S urveys R eport of Investigation 2015-6, 64 p., 45 sh eets, scale 1:63,360. h ttp://doi.org/10.14509/29444 ^n1 NIKOLAI GR EENS TONE, LOW ER MEMBER (LATE TR IAS S IC)— Dark gray-green ^Psv clastic rocks, m assive greenstone flow s, m etagrayw acke, and argillite. Metam orph osed W indy Creek area, S m ith (1981) interprets th ese intrusions as h aving been em placed ph yllite, and lesser ph yllitic m etagreyw acke, greensch ist, calcareous ph yllite, and of interlayered sedim entary and volcanic rocks of Perm ian to Triassic age, including m etabasalt flow s, including pillow structures and m inor flow breccia. Oth er m inor to greensch ist facies. Zircons from th is unit yield a Perm ian (277.3 ± 11.8 Ma) U-Pb MIS CELLANEOUS MAP S Y MBOLS Rose, A.W., 1965, Geology and m ineral deposits of th e R ainy Creek area, Mt. Hayes Q uadrangle, Alaska: Alaska Division of prior to th e final stages of Late Cretaceous m etam orph ism . In th e Butte Creek area, quartz-rich m arble. Fine-grained; grain size approxim ately 0.05 to 0.1 m m . argillite, ch ert, sh ale, lim estone, volcaniclastic rocks, pyroclastic deposits, and Mines and Minerals Geologic R eport 14, 57 p., 1 sh eet, scale 1:36,000. h ttp://doi.org/10.14509/343 interlayered lith ologies include aquagene and epiclastic tuff, breccia, argillite, and m agm atic crystallization age (m ap location U6; Tw elker and O'S ullivan, 2016). Th is A A' th e intrusions are strongly altered to sericite, clay, and pyrite (Kline and oth ers, 1990). Metam orph osed to upper greensch ist facies, evidenced by actinolite, epidote, and andesitic to basaltic flow s. Larger beds of Perm ian lim estone w ith in th is unit are Rose, A.W., 1966, Geological and geoch em ical investigations in th e Eureka Creek and R ainy Creek areas, Mt. Hayes ch ert. Metam orph osed to low er greensch ist facies. For th e purposes of th is m ap, age, and th e interlayered volcanic and sedim entary nature of th e unit protolith s, CR OS S S ECTION LINE AND LABEL ch lorite, plus local biotite and garnet. Detrital zircon spectra from th is unit (m ap ^n1 ^n1 m apped as unit Pl. Metam orph osed to low er greensch ist facies. Fossils from w ith in th is Q uadrangle, Alaska: Alaska Division of Mines and Minerals Geologic R eport 20, 41 p., 3 sh eets. h ttp://doi.org/10.14509/349 GNEIS S OS E GR ANITIC R OCKS (LATE CR ETACEOUS TO PALEOGENE)— greenstones of unit h ave less th an about 1.4 percent TiO2. Unit occurs suggest a correlation to Perm ian portions of th e sedim entary and volcanic rocks of unit :Kgg location DZ8, W aldien and oth ers, 2020; m ap location DZ9, Holm -Denom a and oth ers, ^n2 unit indicate m ainly Perm ian ages (m ap locations F16, F18, F20, F21, F25 [Nokleberg " Saltus, R.W., and Simmons, G.C., 1997, Com posite and m erged aerom agnetic data for Alaska; a w eb site for distribution of Gneissose, fine- to m edium -grained granodiorite, diorite, quartz diorite, trondh jem ite, discontinuously across th e m ap area, and it predates and underlies unit . Th e m ap ^Psv. GEOCHR ONOLOGY S AMPLE 2020) sh ow a single prom inent Late J urassic population. Th is unit occurs along th e ^n1 and oth ers, 1992], F14 [Kline and oth ers, 1990], F24 [S ilberling and oth ers, 1981]) and gridded data and plot files: U.S . Geological S urvey Open-File R eport 97-520, 15 p. h ttps://pubs.usgs.gov/of/1997/ofr-97-0520/ quartz m onzonite, and m inor granite. Ch aracterized by relict igneous m ineralogy and distribution and stratigraph ic position of (a geoch em ically defined unit) are north w estern m argin of th e m ap as a fault-bound belt, separated from th e Maclaren sim ilar to, but not entirely th e sam e as, th at of pillow ed greenstone units (defined by locally Early Triassic ages (m ap locations F10, F11; S ilberling and oth ers, 1981). FOS S IL LOCALITY Silberling, N.J., Richter, D.H., Jones, D.L., and Coney, P.C., 1981, Geologic m ap of th e bedrock part of th e Healy A-1 textures, as w ell as a penetrative foliation defined by aligned biotite and w h ite m ica, Kms sch ist ( ) by a south -vergent th rust fault or by th e V aldez Creek sh ear zone. It is depositional environm ent) m apped at th e base of th e Nikolai Greenstone by previous Greene and oth ers (2010) interpret a regional unconform ity w ith in or above th is unit, Q uadrangle south of th e Talkeetna-Broxson Gulch fault system , Clearw ater Mountains, Alaska: U.S . Geological S urvey Open- plus elongate grains and augens of quartz and feldspar; th is fabric parallels th at of th e File R eport 81-1288, 1 sh eet, scale 1:63,360. separated from th e J urassic-Cretaceous argillite (unit KJa) by unnam ed faults, but it ^tlb ^np separating Perm ian strata from locally docum ented occurrences of Early to Middle [^um] Maclaren sch ist (unit Km s). U-Pb zircon dating indicates a m agm atic crystallization w orkers ( of S tout, 1976; of S ilberling and oth ers, 1981). CONCEALED MAP UNIT INFER R ED FR OM GEOPHY S ICAL DATA sh ares sim ilar sedim entary provenance. Triassic sedim entary rocks and th e overlying Late Triassic Nikolai Greenstone (units Smith, T.E., 1981, Geology of th e Clearw ater Mountains, south -central Alaska: Alaska Division of Geological & Geoph ysical age of 70 Ma (Nokleberg and oth ers, 1992). Th is unit is part of th e East S usitna ^n1, ^n2) and R ainy Creek picrite (unit ^rcp). ^um? IDENTITY OR EX IS TENCE OF MAP UNIT IS Q UES TIONABLE S urveys Geologic R eport 60, 72 p., 3 sh eets, scale 1:63,360. h ttp://doi.org/10.14509/406 bath olith of Nokleberg and oth ers (2015). Smith, T.E., Albanese, M.D., and Kline, G.L., 1988, Geologic m ap of th e Healy A-2 Q uadrangle, Alaska: Alaska Division of ^um* IDENTITY OR EX IS TENCE OF MAP UNIT IS PR OBABLE Geological & Geoph ysical S urveys Professional R eport 95, 1 sh eet, scale 1:63,360. h ttp://doi.org/10.14509/2276 Stevens, D.L., 1971, Geology and geoch em istry of th e Denali Prospect, Clearw ater Mountains, Alaska: University of Alaska U A DIR ECTION OF APPAR ENT R ELATIV E FAULT MOV EMENT Fairbanks, Ph .D. dissertation, 81 p., illust., m aps (4 folded), ph otos. D T U, upth row n block; D, dow nth row n block Stout, J.H., 1976, Geology of th e Eureka Creek area, east-central Alaska R ange: Alaska Division of Geological & Geoph ysical BEDROCK GEOLOGIC MAP OF THE EASTERN DENALI HIGHWAY AREA, MOUNT HAYES, HEALY, AND TALKEETNA MOUNTAINS QUADRANGLES, ALASKA A, aw ay from view er; T, tow ards view er S urveys Geologic R eport 46, 32 p., 1 sh eet, scale 1:63,360. h ttp://doi.org/10.14509/374 Turner, D.L., and Smith, T.E., 1974, Geoch ronology and generalized geology of th e central Alaska R ange, Clearw ater Mountains, and north ern Talkeetna Mountains: Alaska Division of Geological & Geoph ysical S urveys Alaska Open-File R eport The State of Alaska makes no expressed or implied warranties (including warranties for by 72, 13 p., 1 sh eet, scale 1:250,000. h ttp://doi.org/10.14509/167 merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Twelker, Evan, and O'Sullivan, P.B., 2016, U-Pb zircon age data from m eta-igneous rocks in th e Clearw ater Mountains, Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by Evan Tw elker1, T.S . W aldien2, R .J . New berry3, L.K. Freem an1, K.R . S icard1, L.L. Lande1, Alicja W ypych 1, D.A. R eioux1, and E.N. Bach m ann1 Mount Hayes A-6 Q uadrangle, Alaska: Alaska Division of Geological & Geoph ysical S urveys R aw Data File 2016-8, 17 p. the user or any other person or entity whether from the use of the electronic services or products or -150° -147° -144° h ttp://doi.org/10.14509/29663 any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or 1 Affiliation: 64° 17 /2° Twelker, Evan, Lande, L.L., Newberry, R.J., Wypych, Alicja, Sicard, K.R., and Freeman, L.K., 2020, Magm atic and anyone else exceed the fee paid for the electronic service or product. 2020 1 M O U NT HAY ES Alaska Division of Geological & Geoph ysical S urveys, 3354 College R oad, Fairbanks, AK 99709-3707 structural fram ew ork of PGE and oth er m ineralization in north w estern W rangellia, central Alaska: Alaska Division of Geological
H 2 T H Earth and Planetary S ciences, University California-Davis, 2119 Earth and Ph ysical S ciences, One S h ields Avenue, Davis, CA 95616 & Geoph ysical S urveys R eport of Investigation 2020-6, 72 p. h ttp://doi.org/10.14509/30468 R HEALY T O Publications produced by the Division of Geological & Geophysical Surveys (DGGS) are available R SCALE 1:100 000 3 N ALASKA 63° O Shaded-relief base map from: Departm ent of Geosciences, University of Alaska, P.O. Box 755780, Fairbanks, AK 99775-5780 N
C Waldien, T.S., 2015, Evolution of a range-boundary th rust in a strike-slip fault system : Th e late Miocene-R ecent slip h istory of for download from the DGGS website (dggs.alaska.gov). Publications on paper or digital media can I 1 0 1 2 3 4 5 6 7 8 MILES
E T
E U U.S . Geological S urvey IFS AR Digital Terrain Model (2010) th e McCallum Creek fault, Eastern Alaska R ange, Alaska: Davis, California, University of California, Davis, M.S . th esis, 118 p. N R
be examined or purchased in the Fairbanks office: 63° T G Geologic GIS data layers created by: A Hydrology from: M 1 0 1 2 3 4 5 6 7 8 9 10 KILOMETERS Evan Tw elker (2015, 2017) Waldien, T.S., and Roeske, S.M., 2017, Geologic Map of Broxson Gulch , eastern Alaska R ange, Alaska: Geological S ociety of GU LKANA U.S . Geological survey National Hydrologic Dataset (2017) STATE OF ALASKA T ALKEET NA Geologic field investigations by: Cartography by: Am erica Abstracts w ith Program s, v. 49, n. 6. h ttps://doi.org/10.1130/abs/2017AM-307791 M O U NT AINS Projection: DEPARTMENT OF NATURAL RESOURCES M AP LO CAT IO N 62° APPRO XIM AT E M EAN Evan Tw elker (2013, 2015), R .J . New berry (2013, 2015), L.K. Freem an (2013, 2015), Evan Tw elker (2020) Waldien, T.S., Roeske, S.M., Benowitz, J.A., and Twelker, Evan, and Miller, M.S., 2020, Oligocene-Neogene lith osph eric- DECLINAT IO N, 2015 Universal Transverse Mercator Zone 6N DIVISION OF GEOLOGICAL & GEOPHYSICAL SURVEYS -150° -147° -144° K.R . S icard (2013, 2015), L.L. Lande (2015), Alicja W ypych (2015), D.A. R eioux (2013, 2015), Cartographic review by: scale reactivation of Mesozoic terrane accretionary structures in th e Alaska R ange suture zone, south ern Alaska, US A: Geological ♦ Datum: 3354 College Road Fairbanks, Alaska 99709-3707 E.N. Bach m ann (2013), T.C. W righ t (2013), A.L. Tuzzolino (2013), T.S . W aldien (2013, 2015, 2016, 2018) P.G. Ekberg (2020) S ociety of Am erica Bulletin, 26 p. h ttps://doi.org/10.1130/B35665.1 ♦ Location of Map Area North Am erican Datum of 1983 Phone 907-451-5010 Fax 907-451-5050 Geologic interpretation by: Peer review by: Wilson, F.H., Hults, C.P., Mull, C.G., and Karl, S.M., 2015, Geologic m ap of Alaska: U.S . Geological S urvey S cientific ♦ email: [email protected] website: dggs.alaska.gov Evan Tw elker (2015, 2017); T.S . W aldien (2017, 2019) C. P. Hults and S .M. R oeske (2019) Investigations Map 3340, 197 p., 2 sh eets, scale 1:1,584,000.