Virginia Open File Report 09-02 Department of Geologic Map of the Staffordsville Quadrangle Mines, Minerals and Energy Virginia Division of Geology and Mineral Resources GEOLOGIC MAP OF STAFFORDSVILLE QUADRANGLE, VIRGINIA Geology by Arthur P. Schultz and Mervin J. Bartholomew (NARROWS) 2009 DESCRIPTION OF MAP UNITS
(EGGLESTON)
80° 45’ 80° 37’ 30’’
o C (PEARISBURG) B 74 (
37° 15’ o o 75 o o 37° 15’
18 12 30 o 75 77
o 28 o o 38 35 o o o QUATERNARY
20 o o 18 o 68 o o 81 71
o 51s
(
o ( o o 29 22 36 13 o 67 43 (
o o o
o 22 46 37 55 (
o o o o o o o
o o o o 78 74 o 50
o ^
29 o 42
34 o
o 34 o 14
o 48 ^ 38 o Eggleston and Bays Formations, undivided: Interbedded greenish-gray, calcar-
23 o 44 o o 58
16 12 25 o 39 10 o o 40 o 83 68 62 Obe
24 o 84 o 24 ( ( 26 36 30 o o 55 o 45 o 17 o 21 (
20 o o o 41 o 80 o o
18 o o 58 54 o
33 o o o 40 o ^ 76 o 70 o Modified land: Man-made alterations including mine dumps. eous mudstone and dark greenish-gray, fine-grained limestone with interbeds of
o 40 53 o 49 24 88 34 o 66 o ml
( 40 o
44 35 o o ^ ^ 65 58 o 60 67
o o o o 35 66 ( 63 o
o 23 o 38 49 61 37 8 50 ( o o 5 o
23 46 66 o ^ o o siltstone comprise the upper portion of the unit (Eggleston Formation). Lime-
o o 2 47 o o
o o 32 o 36 88 o o 58 64 64 o14 ( 70 o
42 89 o o
66 o o
44 o (
51 o o 81 36 o 66 41 o 57
25 70 ( o o Alluvium: Unconsolidated light-gray to light-brown sand, silt, and clay, with stone content decreases downward as siltstone and calcareous sandstone content
o 42 o 68 (
o 41 o 50 o 13 67 o o o 45 o Qal o o 58 60 5
34 35 40 o 47 88 o 88 35 72
o o
o ( o 85 44 ( o
o o 44 38 o o o o channels and lenses of pebbles, cobbles, and boulders of quartzite, sandstone, and increases, so that the lower unit is primarily fine- to medium-grained, and locally
o 71 o 50 o
33 o 60o 73 71 76 o 61 o
37 41 12 13 o o o o 63 66 o 85 o ^
s o ( o 65 11 ( o o 23 o 55 o 60 o chert. Deposits are stratified and often crossbedded and/or graded bedded. Thick- coarse-grained, greenish-gray calcareous sandstone with a few interbeds of 45 o 47 74 60 o 57 79 67 64
o o o 57 65 47 o o
41 o 41 o 77 54 58 o o o 43 38 30 87 ( o o 60 o69
o o 30 69 51 nesses from less than 1 to more than 30 feet (0.3 to 9 m). maroon siltstone at base of unit (Bays Formation). Total thickness is about 60 feet
49 47 25^ 64 o 50 56 o o
o 19 o o o
44 38 o 54 62 o o ( o 60 o 84
o o 88 o o 67 o
o 40 ^ 75 o57 80 52 82 o (18 m).
o ^o 45 o o ( 50o o
34 o 65 o 27 o
37 o 81 ( 59 45 o
38 47 o o o77 o o 60 65 o o
o 26 47 40 10 80 75 66 40 o
o 29 37 o ( o Sinkholes: Areas mapped as sinkhole topography consist of rolling low hills with ( 46
78 o o o 50 o 29 o 39 o o 60
o 30 ( ^ o o 5 o o 15 55
33 o 83 o 59 49 o o ^ 58o o ^ o 55
o 14 o 60 o round to irregularly shaped sinkholes, clusters of sinkholes, or cave openings. Moccasin Formation: Interbedded maroon and greenish-gray calcareous
30 o 68 75 o 76
o o 45 69
35 ( o ( o o Om
34 o 45 84 25 34 70 50 o
32 ( o 55
25 15 o o o 72
o o 34 ^ 35 58 ( These features have formed from solution or collapse of carbonate bedrock. mudstone with thin beds of fine-grained, medium-gray limestone and maroon o
o o 42 o 83 o 50 20 o o 60
o ( o 48 ^ v
o 38 o 64 o
^ 25
29 ^ 20 88 o62 o 41 39 o o
22 32 28 o 33 o 73 78 40 o 58 49 Sinkholes are delineated from closed depression contours on the 1:24,000 scale siltstone. The lower 3 to 5 feet (0.9 to 1.5 m) of the unit is pinkish-gray to maroon
o o
54 ( 15 o o
39 (
o 81 70 ( o o 68
38 37 o o o
o 57
40 o o 51 o ( ^ 34 40
34 ( o
o o 46 ( 26 o o topographic map. The most extensive sinkholes occur in limestone bedrock of the limestone. The thickness is estimated to be about 50 feet (15 m).
o 5 ^ 12 o 75 o 63
o 24 o ( 14
22 30 o 34 o o o 49
o
48 (
26 o o o 17 o o 86 55 o ( 79 75
o 76 o 67 40
83 o 85 o Conococheague Formation, however sinkholes also occur in other carbonate
o
v ( 42 o
40 o o o o o 38 o 75 88 o 21 27
33 40 o 79 80 o o
20 35 o 33 o46 68 oo 80 70 o 61
o 40 77 63 o ^ o ( o rocks of Cambro-Ordovician age. Middle Ordovician limestone, undivided, upper member: Thin to medium-
o ( o 24 oo
o 65 84 v o
86 87 v 19 Olsu ^
o 24 v o o
o 30 o 3 60 ( 49 24 o (
o o 30 o o
22 o 41 50 o 72 60 bedded, light gray, oncolitic skeletal limestone, pellet and ooid limestone, lime 23 36 (
15 o ( o
26 37 o o o 42 48 44 69 o 67
33 85 ( o o
o
( o
o o s 56
35 46 69 o Debris deposits: Unsorted, angular to rounded, boulders, cobbles, and pebbles of mudstone, and thin buff shales. Includes Whitten, Wassum and Wardell Forma- ( o
o 54 o
o 22 31 o o o o Qd
25 22 o 54 65 ( o 56
o
43 o o 76 o
29 o
o 29 o 40 85 77 59 69 o o o o sandstone, quartzite, siltstone, shale, chert, and minor rock types within a matrix tions of Cooper (1961). This unit overlies nodular, thin-bedded, dark gray to 68 (
28 44 o ( o o
o o 33 40 o 53 o 60
21 o o 64 o o 55 ^
o o ( 60 84 o o
56 46 o 78 o o 60
o o o o
o 34 23 40 40 60 o 35 80 64 62 46 o of sand, silt, and clay. Deposits range from 3 feet (1 m) to greater than 30 feet (10 black, shaly skeletal limestone that includes the Benbolt and Chatham Hill Forma- o o 60
( o
55 o ( s 55 42
31 38o o o 57 44 o
(
o 43 o o 29 81 o 69 o 88
77 46 71 43 o 72 m) in thickness and include alluvial fans, foot-slope deposits, debris fans, debris tions of Cooper (1961). Along the outcrop belts of the Saltville thrust sheet and
28 58 88 o70 66 o
30 ( 18 o 58 40 o o
56 ( o o s ( o ( 44
o o 58 flows, and debris avalanches (Schultz and others, 1991). Deposits typically occur the northwest limb of the Spruce Run syncline this upper member is about 500 o v ( o o
42 o ( 72 84 o o
^ 4o 7 76 o 51 o o ( 50 45 30 o o 35 o o in narrow V-shaped valleys along steeper mountain slopes and as broad aprons on feet (155 m) thick. Along the southeastern limb of the Spruce Run syncline, as
o 58 o o o o 40 o o 67
o 30( 44 70 62 66 58 62
47 55 30 69 o
16o o 42 o o 89 the adjacent gentler slopes of the valleys. well as farther southwest, this unit is tectonically thinned to as little as 100 feet (30 (
o ( ( 31 30 s o
40 46 ( o o o o 30
o 84 v 64 o 59
72 o 73 o 63 o
o s 56 o o 88 m).
( 40 ( 38
73 ( o46 o o o o ( o
o o o
67 46 40 70 64 o o o ( 32
o 34 69
o 40 (
65 o 54 o 50 60 o
o
72 50 o os 80 68 50 o 49 50 82 Colluvium: Blocky accumulations of erosion resistant boulders and cobbles of o oo o o
( o 67
o 42 o o o
o o o o o o Qc
o o 46 o 43 ( 77 30 62 o 55 o 42 o o 68 53 o o 56
o 69 65 82 34 o 62
38 ( o o o 54 o o 70
75 o 66 73 83 o 85 o o 58 o generally angular sandstone and quartzite with minor amounts of siltstone, shale, r Middle Ordovician limestone, undivided, lower member: Skeletal grainstones o 48
42 38 ( 53 o 52 o 56 60 57 53o 57 65
( o
43 o o 52 56
39 o o 38 89 68 o o o 53 Olsl
38 o 36 2244 64 54 o o 69 63 and chert; includes block streams, block fields, and talus. Deposits range from 0 equivalent to the Effna and Ward Cove Formations of Cooper (1961) overlying ( o 53
37 87 o o 63 36
50 s 40 o o o o40 79 48 53o o
75 o
o 60
o o o o o 57 81 o
50 o o 73 o75 o 32 64 o o
o o
51 ( o 52 58 55 to 30 feet (0 to 9 m) thick and are derived from nearby strata of Mississippian, thick-bedded, dark-gray, burrowed, cherty, fine-grained limestone equivalent to
55 o o 65 43 70
o o 59 o o o o ( 76 (
o o v o
60 ( 84 o
o o o 59 o 38 (
o 55 32 o
o 50 38
83 o 55 o o o 56 47 64 65 Devonian and Silurian age (Schultz and others, 1991). Generally occurs on the the Lincolnshire Formation of Cooper (1961), which is locally oncolitic. This, in 73 22 o o 65o 38o o o 73 58 60 o o 44 51 52
o o o o 56 o 60 o 69
o 89 o 85 56 49 o 50o
81 38 45 o o o higher elevation slopes below bedrock escarpments and may grade downslope turn, overlies thin- and medium-bedded, gray, cherty pellet limestone, fenestral
85 87 o 37 ( o o o o 75
45 v o85 o 39 55 48 47
o o 87 30 o 69
64 o o 50 ( o o 45 29 o
o 43 82 o o
( 52 o o 65 37 into more matrix-supported debris type deposits. limestone and skeletal limestone, light gray shale and shaly limestone in lower ( 55 ( 50
o
o o o 55 o 58
70 o 66 63 v o o 88 ( 79 o 42 o 53 85 37 o o o 56 part, and basal lithoclastic breccias and dolomite that are equivalent to the Black- 77 o 68 o
77 o o 72 o 49 o 60 o o 75 o 51
69 o o 58 62 50 o o 45 o 75 52 ( o 61 o o 39 87 o v 53 63 o o Terrace deposits: Rounded cobbles and boulders of vein quartz, metaquartzite, ford, Elway, and Five Oaks Formations of Cooper (1961). Locally a silicified
86o 63 63 o o 52 53 60 o o Qtd o 53 o o 65 45 72 s 70 o o o 64 64 o 68 o 72 quartzose and feldspathic sandstone, and chert in a dark brown to dark red-brown, carbonate marker bed is present near the base of the lower member. Within the o o 61 o o o 65 54 57 47 31 53 45 42 o o o o o o o extensively weathered soil matrix. Terraces range from 1 to over 30 feet (0.3 to Saltville thrust sheet, the thickness of this member varies considerably along 80 o 46 o 57 58 o 70 o 51 o o o 70 o 41 45 49 37 o 59 o 50 o 44 over 9 m) thick. Terraces associated with New River, Walker Creek, and Back strike. It reaches a maximum thickness of about 500 feet (155 m) where a basal o o 54 54 o 43 46 59 o 69 o o 44 o o Creek range from about 20 feet (6 m) to over 300 feet (90 m) above the present conglomerate with dolomite cobbles is present in a local trough, and then thins to 52 o 42 48o o 53 o 50 68 57
o o o o o o
o 51 o 77 floodplains. In places, discontinuous, 0.5- to 3-inch- (1- to 6- cm-) thick, dark less than 100 feet (30 m) where a high area existed on the underlying unconfor- o o ( 42 45 50 46 o o 54 45 o 17 43 57 o 58 o o o 14 o 67 o Ão 13 48 64o o o o 30 62 o 70 52 red-brown, ferruginous hardpans occur which cement the matrix and clasts of the mity surface. Basal red beds (r) occur locally. Within the Narrows thrust sheet on 58 o 76 45 o 58 o o 67
o 55 52 o o 69 o 62
o 50 48 o o 62 terrace deposits. the northwest flank of the Spruce Run syncline, the lower member is about 350 o 54 ( o o o 72 52 o o 43 47 o o 58 72 o 50 o 85 46 o 61 70 58 41 o o 65 o 49 o o o feet (105 m) thick. Along the southeast limb of the Spruce Run syncline the lower o o 42 o 34 45 o o o 72 o 38 56 o 80 62 o o o o 54 61 Ã
o o 63 61
51 o 53 59 65 o Bedrock landslides: The two general types of bedrock failures on dip slopes member is tectonically thinned to as little as 100 feet (30 m). 34 34 o 55 ( o 43 45 55 o Ql o 42 o o 47 o 66 44 54o 53 o underlain by Silurian and Devonian rocks are coherent bedrock block slides and o o o 43
38 47 55 o 88 o 59 64 o
35 53 o 36 o o 70 gravitational sags or “sackungen” (Schultz, 1986; Schultz and Southworth, 1989; Upper Knox Group, undivided: Medium- to light-gray, fine-grained dolomite o o o ( 43 54 65 o o o o 75 Oku o o o 33 52 o 63 o o 40 o 52 o 50 o o 76 Schultz and others, 1991). Sackungen are large slabs of coherent sandstone and typically in 1- to 3-foot (0.3 to 0.9 m) thick beds which are internally either 35 o o o 35 ¸ 45
67 48 o 53 55
40 o o o o o 44 35 78 (
o o 47 58 o 58 59 quartzite that have rotated or sagged downslope from the crest of the mountain. massive or stylolitically laminated. The unit commonly contains light gray, 42 o 49 o
o o 74 o o o ( o 58 11 43 o 41 o 60 o o 42 51 o o 66 Ã 20 15 These rotated blocks form downslope bulges and open depressions, while linear laminated chert as well as 0.5- to 2.0-foot (15 cm to 0.6 m) thick beds and lenses
50 o 63 o 63 53 Ã o o 48 14 72 o ( valleys along the crest of the mountain forming distinctive double ridges. Sackung of nodular chert that are often irregularly shaped and vuggy. The thickness is
o o
o 47 69 o o o 34 Ã 16 o 54 40 60 o o 63 o 25 ( oo 48 o o 20 14 range from less that 500 feet (150 m) long to upwards of 2000 feet (610 m) long. estimated to be about 1000 feet (305 m). The rocks mapped as upper Knox Group 56 55o o
42 65 66 56 29 o o
o o o 29
60 o 53 o ( 18 Bedrock landslides consist of large rotated slabs of Silurian age sandstone and are equivalent to the Knox Group (upper part) as mapped on the Blacksburg quad- o (
37 o o 46 oo 52 54 61 o o o 55 48 o o o
45 50 36 o o o o 38 o 19 quartzite that have detached from the upper slopes of the dip slope and moved rangle (Bartholomew and Lowry, 1979) and the portion of the Knox Group as 45 o 46 ^
o 40 47 64 66 17 ( o 16
47 o o o o o 69o 30 o o 47 77 70 ( 44 25 toward the valley bottom. These features range from less that 300 feet (90 m) to described by Cooper (1961) and the Beekmantown Formation of Butts (1933, 50 o o o 10 2 35
o68 34 ^ o
44 o o o o 16 35 o 21 greater than 2000 feet (610 m) long. 1940).
o o 62 o 61 o 17 31 18 68 o
o 31 o 78 o 58 59 o 59 64 o o o o
80 o ^ 20 (
54 o o 7
60 29 50
( 23 o
o o o 53
o o o o o 47 MISSISSIPPIAN ORDOVICIAN AND CAMBRIAN 35 o 22o ^ 23 49 o34 55 58 o 5 33 25 o o 22 o 34 55 o o 13 38
56 o 53 50 o o ( o o
65 o 60 10
20 o o (
( o 35 o o o o o o16 ( o 54 o19 o 44 55 68 20 50o38 Maccrady Formation (lower member): Dominantly mottled maroon and green Conococheague Formation: Cyclic 3- to 4.5-feet (0.9 to 1.4 m) thick sequences
o 50 46 o o o 40 25 o o 20 d s
o 55 54 70 o 26 o o Mmcl
46 o ^ (
o 28 35 o
o 47 o 35 ( mudstone in 20- to 50-foot- (6 to 15 m) thick sequences with interbedded of basal intraformational limestone- and dolomite-clast conglomeratic limestone
53 25 (
82 24 o 30
52 o 38 42 o
o o 34 o
( 34 47 o o o 39 40 o ( o 55 o o 58 o 18 10 34 20 o sandstone, minor siltstone, and dolomite beds. Interbedded sandstones are overlain by millimeter to centimeter laminated blue gray limestone. This part of 47 o 25 ^
59 53 o o 16 o 24
o o o o 41
o 40 50 o 35 o 41
o 40 o o typically medium-gray, 1 to 3 feet (0.3 to 0.9 m) thick, thinly bedded, fine- to the cycle is overlain by bluish-gray “ribbon” limestone. Tops of the cycles are
o 40 o 12
o (
65 o69 Ã Æ o 30 o 29 33 o o o 72 40
50 57 ( 22 34 o Ã
o o 48 o 45 v
( 67 medium-grained, and contain both feldspathic rock fragments and mica. Near the capped by blocky, light gray dolomite. In places, the upper part of the cycles may
o 50 36 o ^ o o o ^ 25
60 o o o o 2 52 30 ( 45 25 32 o 49 oo
53 28 13 7 o o 24 o 29 base of the formation, a thick sequence of maroon, medium- to coarse-grained, consist of light pink dolomitic mudstone. These cycles are interbedded with o 28 o 25 o 27 o o
o o o o 75 o
60 o 35 24 49 o 34 55 o ( ( 13 63 o 24 29 36 34 cross-bedded sandstones occur. Scattered 1- to 3-foot (0.3 to 0.9 m) lenses and chert-bearing stromatolitic dark gray limestone, light pink limestone and
70 ^ o o
o o o 15 o 58 o o48 41o à o 24 o ( 34 beds of olive-gray to medium-gray or mottled maroon and gray, fine-grained, dolomite, rippled and mud-cracked light gray limestone and dolomite, and
o 43 o o 12 28 o 25 62 o
o 57 27 25 o 32 48 32 49 o 16 o o (
54 23 o19 o o 80 o
55 o ( o massive to nodular-bedded dolomite also occur (d), primarily near the contact distinctively white weathered, highly fractured, blocky dolomite and oolitic chert.
o o ( oo 65 o o ( 55
46 38 o o 54 23 43 35 39 56
52o 53 o 36o o 44 with the underlying Price Formation. The lower Maccrady is about 600 feet (185 Discontinuous, medium- to fine-grained, light gray, 1- to 8-inch (2.5 to 20 cm) o 59 o
o 33 o 27 o54
o o ( 33 o
29 o 45 o o34 54 ( o o
55 o m) thick and is characteristically veneered by a thin maroon soil. The upper thick carbonate cemented quartz sandstones (s) are present near the base of the
o o 34 38 o 70 (WHITE GATE) ( o 34
40 o 20 o 45 o 38 50 28 40 42 o ( 56 o o
49 30 18 o o member is tectonically removed by the Pulaski fault. unit and throughout the section but exposures are relatively rare. Total thickness
o Æ o 26 o 44
o ( o
o o 30 43
48 o 25 o o
o 73 25 o ( o 10 is between 1800 and 2000 feet (550 and 610 m).
o 29
35 24 o
50 23 o38 28 o 82 o o
o ( o
o o o o o 53 69 65 ^ 62 ( o
31 o 39 ( Price Formation (upper member): Gray, quartzose sandstone, mottled maroon
30 25 o87 o d
o o 16 o 85 15 26 26 Mpru
58 63 o 30 o o o Æ o o
o o (RADFORD NORTH)
30 30 o40 47 39 66 and green mudstone, dark-gray siltstone, and black mudstone and/or coal. The CAMBRIAN o 35 (
o 64 66 o 40 23 (
( o 22 o o 48
62 o( o 34
o 26
o 44 48 ( o coal measures are found near the base of this member except for a local bed at the
o o o
35 o o 64 o
47 66 o 49 o ( 18
o 30 o 59 o o 53 ( o o o o o 36 o 37 21 55 Bell Hampton Mine, which is at a stratigraphically higher position. Most coal s Copper Ridge Formation: Medium- to light-gray, fine-grained dolomite
37o 25 o o 63 49 o 42
40 41 o
o 30 o 52 o o 79 35 65 (
32 43 35 30 o o beds appear to be laterally discontinuous over distances of just a few miles. typically in 1- to 3-foot (0.3 to 0.9 m) thick beds, algal laminated and often
o 53 o (
37 ( 65 50
o 50 o 44o o 48 38 Quartzose sandstone is typically medium- to brownish-gray, medium- to coarse- interbedded with lenses of dolomitic, quartzose sandstones and nodular,
o o o
o 33 45 19 o 55 o o o
o 30 o ^ 69 o
44 35 38 o o76 22 grained, cross-bedded, and contains abundant feldspathic rock fragments and laminated chert. Silicified carbonate sandstones (s), which range up to 4 feet (1.2
o ( 78 42 Æ o o
o 68
^ o 69 o45 12
Æ 56 55 e 29 o o
( o 63 o o 48 o 58
( 35 34 o o mica. Medium-gray siltstone is thinly bedded and, below coal beds, disrupted by m) thick, occur as discontinuous beds and lenses. Stromatolites and cross-bedded
Æ 66 o
A 66 o 49 o o
5 o o o 15 37 o (
64 42 Æo 60 35 30 34 ( o 46
o o 50 o o 35 60o o
o ( 60 roots. The member is generally covered by 1 to 3 feet (0.3 to 0.9 m) of light silicified oolites are present locally. Approximately 1000 feet (305 m) thick. The 51 o o
o 45 50 (
( o 42 58 o 90 o
o46 o 42 64
o 58 o o ( o
67 o o o o o
o 67 ( 42 16 26 16 39 brown, sandy soil. The unit thins southwestward from about 1500 feet (460 m) to Copper Ridge is mapped on the Narrows and Saltville thrust sheets and is roughly o
o 52 o o
o
70 o à 49 47 o 52 30 o
o o ( 67 56 57 73 ( 65 42 o o o 61 4
o o o 42 70 o 63 about 1000 feet (305 m). equivalent to the Conococheague on the Pulaski thrust sheet.
63 35 24 o 46o62 o 71 31 40 o o ( 44 ( o80 68 o o
o 48 Ã o 38 o o 21
( oo o o 58 24 23
o o 54 58 o
34 o o 60 26 45 75 65 o o o o 31 35 o ( 44
39 o 57 23 o o 39 o 40 o
55 o 21 43 8
o o o o 24 Price Formation (lower member): Interbedded sandstone and siltstone, the Nolichucky Formation: Medium- to light-gray, thin-bedded, argillaceous
( o 73 43 34 o o
( 10 o
41 o Mprl
26 o o 61 o 37 o 49 19
45 ( ( 32
o o
o o 58 38 ( siltstone content increases southwestward along outcrop belt. Both the dolomite. The unit is approximately 20 feet (6 m) thick. The Nolichucky is
( 39 65 o
56 o 24 o o o o42 o
35 o o 34 o
o 59
25 o 83 o 27 fine-grained to medium-grained sandstone and the siltstone are medium-gray, present only on the Narrows and Saltville thrust sheet and is roughly equivalent to à o 25
o
o78 o o ^
(
( 62 63 36
66 8 57 83 35 o ( o o o o
o 53 o 49 ( 70 o 36
o 33 25 o o platy (due to alignment of mica flakes parallel to bedding or cross-bedding), well the upper Elbrook of the Pulaski thrust sheet.
o 68 o
o o 67 o 68 o 24 18 45 o
45 20 o o 54 81 42 30 o
o o 45 o29 o o o 33 o o o
o
58 65 ( 75 49 50
o o o 62 18 28 44 layered or cross-bedded, and contain abundant feldspathic rock fragments and
42 o
( 16 65 o o o 44
o 73 o o o ^
( o 33 o o 60 40 o 87 71
51 88 ( 46 48 o
51 o o 7 82 25 o 34 o 72
o o o
o o o o 26 ^ mica. Clay-gall conglomerates and medium-gray mudstone beds occur locally. A Honaker Formation: Medium- to light-gray, poorly algal laminated to styloliti- o o
41 25 56 o 16
54 5 o ( 33 36 53 o ^ 63 64 (
49 o 68 o o
o ^e 35 o 35 o 28 43 o 31 o 27 thin, light-brown, sandy soil typically covers this map unit. The lower member is cally laminated, fine-grained dolomite in 1- to 3-foot (0.3 to 0.9 m) beds. o 65 o
Æ 42 53 38 44 o o o o o o
o 38 ( 45 o 46 52 o o ( o 24o
44 55 68 o 60 36 16 o71 43 about 1000 feet (305 m) thick and is stratigraphically underlain by the basal Cloyd Stylolitic laminations often form pink partings. Chert occurs as nodules generally
à o o o23 53 o20 15 48 o (
o 35 58 o
o
52 (
54 o 85 o 10 Conglomerate Member of the Price Formation. 4 inches (10 cm) or less across. Minor limestone beds occur in the lower part of
o
^ 41 o (
o 71 28 ( o ( o
à 46 o (
54 75 o30 30 70 44 ^
o ( the Honaker Formation. Approximately 2,300 feet (705 m) of Honaker occurs in o 36
o o 46 (
o
o o o 64
54 o 30 8 68 ^ 19 (
^ o
44 ( 4 1 ( o ( 70 v Price Formation (basal Cloyd Conglomerate Member): Consists of 20 to 60 the hanging wall of the Saltville fault on the western edge of the area. To the
o o 10 28 Mprc
70 o 54 o o ( o o 59 33 o ( 74 79 16 18 feet (6 to 18 m) of massive to very thick bedded, cross-bedded sequences, grading northeast most of the Honaker is truncated by the Saltville fault. Within the
o o 25
51 o o
o 25 o o ( o o o 89 o from quartz-cobble conglomerate at the base to quartz-pebble conglomerate to Narrows thrust sheet, the Honaker is about 2,800 feet (855 m) thick. The Honaker
55 64 55 61 o 37 34 o 47 15 (
s 25 o43 44 26 o 45 ( o o ( coarse-grained sandy conglomerate at the top. A thin veneer of quartz gravel and mapped on the Narrows and Saltville thrust sheets is roughly equivalent to the o o 12 33 B’
o o 63 40 o
o
54 o o 85 26 sand commonly form a loose soil between the abundant outcrops of this member. middle and lower Elbrook of the Pulaski thrust sheet.
62 (
o 24
( o 14
o o 52 o
o o (
49 ( 80 82 o
55 ( 73 o 45 19 o
o 40 DEVONIAN Elbrook Formation: Upper part consists of 3- to 20-foot (0.9 to 6 m) thick
o 12
78 54 o
o o (
o
o o alternating tan and gray, irregularly banded, partially dolomitized limestone
o64 ( 47 34 o o o
o 82 o 61 34 12
72 o 40 68 o 48 88 o 12 ^
69 o Foreknobs Formation: Cyclic sequences of dark-gray to brownish-gray or interbedded with 1- to 3-foot (0.3 to 0.9 m) thick stylolitic, dark gray, fine-grained
( o o ( o
o 62 55 25 Dfk
( 29 e 20 24 ( o reddish-gray, fine- to medium-grained, fossiliferous, graded beds of sandstone dolomitic limestone and massive bedded, 3- to 6-foot (0.9 to 1.8 m) thick, thromb-
o o o o o 24 22
o32 46 34 o o 12
o ( 25 19 and siltstone with minor mudstone. Most of the sequences are truncated by the olitic dolomite. Occasional 5- to 10-foot (1.5 to 3 m) thick cyclic packages of 1.5-
68 (
o o (
45 88 o o 22 o 21
( overlying sequence producing 3- to 20-foot- (0.9 to 6.0 m) thick sandstone ledges to 2.5-inch (4 to 6 cm) thick intraformational dolomite clasts, limestone conglom-
41 55 29 o o e ( o 31
o o 26 o
o o
14 o 34 36 16 that are thicker and more abundant near the top of the formation and thinner near erate are overlain by 1- to 3-foot (0.3 to 0.9 m) thick ribbon banded, partially
14 ( o
62 ( o o
o
29 ( the base. Total thickness is about 800 feet (245 m). dolomitized limestone overlain by 3-foot (1 m) thick massive dolomite. Middle 8 28 e
85 o
o 75 24 6 o o 43 o (
o o 21 part consists of cyclic sequences 3- to 20-foot (0.9 to 6 m) thick, partially
51 o 47 o
18 ( 85 o o v o 23 o
80 Brallier Formation: Cyclic sequences of 2- to 6-inch- (5 to 15 cm) thick beds of dolomitized, wavy laminated limestone with 1- to 10-foot (0.3 to 3 m) thick, o Db
v 43 o o o o 9
34 24 o 33 70 ( 32 16 medium-gray, well-laminated, commonly crossbedded, fine-grained sandstone centimeter-laminated, light-gray, argillaceous dolomite and 1- to 15-foot (0.3 to
o
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39 24 o 16 and siltstone overlain by dark-gray to black mudstone. The thickness and percent- 4.5 m) thick cherty dolomite with thin evaporite-disrupted laminations. The
10 o
o 30 16 o o
o o o 34 o
34 ( 17 age of the sandstone and siltstone beds decrease downward so that mudstone lower part of the middle section consists of cyclic interbedded sequences of 3- to
85 18 o o 17 7 ( o 16 o ( 18
14 o
o o ( 5 14 predominates over the coarser clastics near the base and vice versa near the top of 20-foot (0.9 to 6 m) thick, flat and stromatalitic algal laminates and 1- to 10-foot 24 24 o
o o o
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27 ( o the formation. Thickness ranges from about 2000 to 3500 feet (610 to 1070 m). (0.3 to 3 m) thick centimeter-laminated argillaceous dolomite. The lower Elbrook
23 19 18
o 14 15 (
38 o o o
o o o 10 is dominantly 15- to 30-foot (4.5 to 9 m) thick centimeter-laminated, argillaceous
45 o o
23 23 ( 74 o o
( 24 10 15 Millboro Shale: Dark-gray to black, thinly bedded, sparsely fossiliferous, fissile dolomite, 3- to 10-foot (0.9 to 3 m) thick, massive bedded, light-gray dolomite
o 24 63 o Dm
o o 11
o 19 ( 4 o
55 ( 54 o mudstone and black shale. Contains abundant concretions and disseminated and 3- to 20-foot (0.9 to 6 m) thick algal laminated dark-gray dolomite and
56 o o 23 (
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o o o sulfides as well as a few thin beds of carbonate. Thickness ranges from about dolomitic limestone. Light olive-green and pale-pink argillaceous dolomite
o 20
14 10 o ( o
( o o 26 o 23 o 26
o 4 35 o (
18 13 ( 23 1000 to 1300 feet (305 to 400 m). occurs near the base of the formation. Near Radford an undeformed section of the
24 64 (
o 11 o ( 23 o o
14 ( lowermost Elbrook consists of two 1-foot (0.3 m) thick, maroon phyllitic
o o 17
( 25 14 o
( 21
1 o DEVONIAN AND SILURIAN mudstones interbedded with 3- to 6-foot (0.9 to 1.8 m) thick olive-gray, massive-
o (
51 o
o
o 22 21 ( bedded dolomite and 1- to 6-foot (0.3 to 1.8 m) thick centimeter-laminated ( (
15 ( 45 24
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(
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o Lower Devonian and upper Silurian, undivided: Consists of interbedded dolomite. The total thickness of the Elbrook Formation ranges from 1,800 to
o 41 35
( DS 54 18 o
o light-gray, medium- to coarse-grained quartzose sandstones in 5- to 40-foot thick 2,000 feet (550 to 610 m).
18 o ( o o 16 ( (1.5 to 12 m) ledges, separated by poorly exposed intervals of dark-gray
5
24 o 9 o
26 84 o
o o fine-grained friable sandstones and siltstones with minor mudstones. The thick- Tectonic breccia (Elbrook Formation): Light- to medium-gray, massive to
11 o ( o b 14 ( o o 21 23
o 14 38 o ness is about 60 feet (18 m). crudely-layered, well to poorly indurated breccia consisting of angular to rounded
o 23 o 16 o
35 o 21
o 33 o
( s o 21 13 o ( unsorted clasts of dolomite, limestone and chert in an unsorted matrix of dolomite.
o
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26 29 62 ( o 14 35 24 30 15 o
o
o o o SILURIAN Forms sill- and dike-like bodies up to 50 feet (15 m) thick. A second type of
( o
20 o 21 ( 22 25 o o o
10 o breccia consists of light to medium grayish-green fragments of phyllitic,
o 15 o 24 33 27 ( 19 20
o 26 23 Keefer Sandstone: Light-gray to white, predominantly thick-bedded but also dolomitic mudstone and dolomite in dolomitic cement.
29 o ^ o o Sk
13 o o (
o o 24 21
28 24 15 42 20 massive, cross-bedded, rippled, medium- to coarse-grained quartzose sandstone
43 o o 7 o 29 o o
o o 25 29 o o 45
16 14 o 40 and fine- to medium-grained orthoquartzite. Burrowed beds and minor reddish- Rome Formation: Interbedded mottled maroon and green phyllitic mudstone
22 o o 4 o 22 o o ( 34 o 34 o o 5 o brown sandstone also occur with interbedded minor quartz-pebble conglomerate and very minor 3-foot (0.9 m) thick, dark-gray, fine-grained dolomite. The total
24 o
o 18 24 24
( o 17 o
17 o o 16 32 o ( and greenish-gray siltstone and mudstone lenses. The thickness is approximately thickness of the Rome cannot be determined due to complex folding.
19 13 o o o 10
o 54
o o 16 10
14 21 ( 200 feet (60 m). o o ( 9 o o
23 16 o 5 o o 50 ( o 20 21 o 20 48 26 37° 07’ 30’’ 37° 07’ 30’’ Srh Rose Hill Formation: Interbedded, hematite-cemented, dark-brownish-red, fine- 80° 45’ A’ (DUBLIN) C' 80° 37’ 30’’ REFERENCES (RADFORD to medium-grained, ferruginous sandstone and dark-reddish-gray mottled SCALE 1:24,000 SOUTH) Basemap, modified U.S. Geological Survey DRG MN mudstone and siltstone. Lesser amounts of interbedded, fossiliferous, burrowed 1 0.5 0 1 MILE Bartholomew, M. J., and Lowry, W. D., 1979, Geology of the Blacksburg quadrangle, 1965 Staffordsville Quadrangle, Virginia GN red siltstone and mottled greenish-gray shale. Thickness is approximately 140 feet 10000 1000 2000 3000 4000 5000 6000 7000 FEET Virginia: Division of Mineral Resources Publication 14. (PULASKI) (45 m). o ' Butts, Charles, 1933, Geologic map of the Appalachian Valley of Virginia with Polyconic projection: UTM zone 17, NAD 1927 7 47 1 0.5 0 1 KILOMETER 138 MILS 0o 11 ' explanatory text: Virginia Geological Survey Bulletin 42, 56 p. 3 MILS Tuscarora Formation: Massive, fine-grained, light-gray to white orthoquartzite Digital cartography by Aaron Cross CONTOUR INTERVAL 20 FEET Stu Butts, Charles, 1940, Geology of the Appalachian Valley in Virginia: Virginia Geologi- NATIONAL GEODETIC VERTICAL DATUM OF 1929 interbedded with massive and cross-bedded, medium- to coarse-grained, light- and Elizabeth V. M. Campbell cal Survey Bulletin 52, Pt. I, 568 p. gray to white quartzose sandstone with lenses of quartz-pebble conglomerate and Cooper, B. N., 1961, Grand Appalachian Excursion: Geologic Guidebook #1, 2009 MAGNETIC NORTH greenish-gray siltstone and mudstone. Both trough and planar cross bedding DECLINATION AT CENTER OF SHEET Geology mapped from 1980 to 1983 Engineering Extension Service, Virginia Polytechnic Institute and State Univer- occur throughout the section. Thickness is approximately 100 feet (30 m). sity, Blacksburg, Virginia, 187 p. Schultz, A. P., 1986, Ancient, giant rockslides, Sinking Creek Mountain, southern ORDOVICIAN Appalachians, Virginia: Geology, v. 14, p. 11-14. Schultz, A. P., 1993, Geologic map of large rock block slides at Sinking Creek Moun- Juniata Formation: Predominantly interbedded maroon to dark reddish-brown, Oj tain, Appalachian Valley and Ridge Province, southwestern Virginia, and mottled siltstone and mudstone with thin beds of fine-grained reddish-brown comparison with the Colorado Front Range: U.S. Geological Survey Miscella- sandstone. Fossil Lingula fragments and reduction spots are locally common. The neous Investigations Series, Map I-2370, 1:24,000 scale. ACKNOWLEDGEMENT thickness is about 150 feet (45 m). Schultz, A.P., and Southworth, C. Scott, 1989, Large bedrock landslides of the Appala- chian Valley and Ridge Province of eastern North America: in, Schultz, A.P., and This map was prepared in cooperation with the U.S. Geological Survey under Martinsburg Formation: Upper portion consists of interbedded 0.5- to 1.0-foot Omb Jibson, R.W., eds., Landslide processes of the eastern United States and Puerto the National Cooperative Geologic Mapping Program; 2006-2007 STATEMAP (15 to 30 cm) thick beds of massive, fine-grained, medium-gray sandstone with component, Grant 06HQAG0039 Rico: Geological Society of America Special Paper 236, 57-74. fossil debris and medium-gray well-laminated calcareous mudstone. This grades Schultz, A.P., Bartholomew, M.J., and Lewis, S.E., 1991, Map showing surficial and down section into dominantly medium- to dark-gray, coarse-grained, bioclastic generalized bedrock geology and accompanying side-looking airborne radar SUGGESTED REFERENCE limestone interbedded with medium-gray, well laminated calcareous mudstone. image of the Radford 30 X 60 minute quadrangle, Virginia and West Virginia: The thickness is estimated to be about 1100 feet (335 m). The use of Martinsburg U.S. Geological Survey Miscellaneous Investigations, Map I-2170-A, 1:100,000 Schultz, Arthur P., and Bartholomew, Mervin J., 2009, Geologic Map of the Formation in this area follows past usage by Butts (1933, 1940) and Cooper scale, 2 sheets. Staffordsville quadrangle, Virginia: Virginia Division of Geology and Mineral (1961). Resources Open File Report 09-02, 1:24,000-scale geologic map
MAP SYMBOLS
For all contact, fault, and fold symbols: lines are solid where the location is exact, long-dashed where the location is approximate; short-dashed where the location is inferred; dotted where the location is concealed. Teeth are on the upthrown block.
( Contact, approximate Thrust fault, known o Strike and dip of inclined beds ¸ Shaft
( Contact, covered Thrust fault, approximate v Strike of vertical beds Æ Inactive mine
( s Strike and dip of overturned beds à K Fold axis Thrust fault, inferred Prospect
( e Horizontal beds Adit Thrust fault, covered ^ Strike and plunge of mesoscopic Coal bed Cross fault, fold axis displacement uncertain