STATE OF SOUTH DAKOTA South Dakota Geological Survey M. Michael Rounds, Governor

General Map 11 DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES Black Hills Inset Steven M. Pirner, Secretary DIVISION OF FINANCIAL AND TECHNICAL ASSISTANCE David Templeton, Director

11N GEOLOGICAL SURVEY PROGRAM

- Derric L. Iles, State Geologist 2 5 0 0

- 2 6 - 0 2 0 - 4 2 0 7 0 0 0 - 2 8 0 - 0 2 9 0 0 - 3 0 - Elevation Contour Map of the 2 0 3 0 10 0 0

! <-1240 Precambrian Surface of South Dakota - 2 2 0 0

- 2 1 0 0 - 1 2 0 0 Black Hills Inset

- 1 1 - 1 0 4 0 0 0

- - 1 1 3 6 0 0 0 0 Kelli A. McCormick 9 -2 - 0 1 0 - 5 0 1 0 0 0 0 0 - 1 1 ! 0 9 2010 0 <-943 0 0 - -1 9 7 0 0 0 0 0 - 2 1 0 - - 8 4 8 0 0 0 0 0 0 0

- 1 - - 0 3 6 0 0 0 INTRODUCTION 3 0 0 0 0 The Elevation contour map of the Precambrian surface of South Dakota, Black Hills inset, was created using depth and rock-type data from more than 2,800 drill holes in combination with published depths to the Precambrian basement and Precambrian rock -5 -2 0 types intersected (such as granite and schist), as well as published Precambrian structural contour data within the inset area (see SELECTED REFERENCES). For the Black Hills, where Precambrian rocks are exposed at the surface, elevation contours were 0 0 0 - 7 taken from 1:24,000 scale hypsography (digitized from digital raster graphs or DRGs). These contours were then modified based on drill-hole data in and around outcrop areas. A unique aspect of this map is the inclusion of contours in the outcrop area. 0 0 Inclusion of the contours in the outcrop areas provides a more complete perspective of the configuration of the Precambrian basement in the Black Hills area. DATA 8 The drill-hole data presented on this inset are a small subset of available data. Presented here are Precambrian intersect data from 386 drill holes and an additional 162 drill holes that do not intersect the Precambrian basement but help constrain the contour placement. Because much of the Black Hills inset is represented by outcrop (shown by the green outline), contour spacing on the Precambrian surface is tight, considerably limiting the amount of other data that can be presented on this map. The complete dataset is available for download at the Geological Survey Program, Department of Environment and Natural Resources, website. Further discussion on data sources and drill-hole location is included on the 1:500,000-scale map titled Elevation contour map of the Precambrian surface of South Dakota. <1000 !

400 SELECTED REFERENCES 500 Baker, C.L., 1947, Deep borings of western South Dakota (revised 1953): South Dakota Geological Survey Report of Investigations 57, 112 p. (Revised 1953.) _____1948, Additional well borings in South Dakota: South Dakota Geological Survey Report of Investigations 61, 40 p. (Suppl. Report of Investigations 57.) 600 _____1951, Well borings in South Dakota, 1948-1950: South Dakota Geological Survey Report of Investigations 67, 67 p. (Reprint 1953.) Bretz, R.F., and Barari, A., 1996, Ground-water study for the city of Keystone, South Dakota: South Dakota Geological Survey Open-File Report on Urban and Rural 7 00 Studies 45, 41 p. Brown, B.L., 1959, List of oil and gas tests in South Dakota: South Dakota Geological Survey Circular 30, 18 p. ! Carter, J.M., Driscoll, D.G., and Williamson, J.E., 2002, The Black Hills hydrology study: U.S. Geological Survey Fact Sheet FS-046-02, 6 p., 7 <970 800 http://sd.water.usgs.gov/projects/bhhs/Intro.html [accessed 2008-2009.] 120 1 0 100 Darton, N.H., 1896, Preliminary report on the artesian waters of a portion of the Dakotas: U.S. Geological Survey Annual Report, v. 17, pt. 2, p. 603-694. 9 00 _____1905, Preliminary report on the geology and underground water resources of the central Great Plains: U.S. Geological Survey Professional Paper 32, 433 p. 130 90 0 1 _____1909, Geology and underground waters of South Dakota: U.S. Geological Survey Water-Supply Paper 227, 156 p. ¨¦§ 000 14 ! <2122 00 ! _____1918, Artesian waters in the vicinity of the Black Hills, South Dakota: U.S. Geological Survey Water-Supply Paper 428, 64 p. Darton, N.H., and Smith, W.S.T., 1904, Edgemont folio, South Dakota-Nebraska: U.S. Geological Survey Folios of the Geologic Atlas 108, 10 p. 16 15 1900 00 00 Geological Survey Program, 2010, Core and cuttings repository database: South Dakota Department of Environment and Natural Resources, 2100 http://www.sddenr.net/core/ [accessed 2005-2009.] 180 17 <547 _____2010, Lithologic logs database: South Dakota Department of Environment and Natural Resources, http://www.sddenr.net/lithdb/ [accessed 2005-2009.] 2 0 00 22 000 Lidiak, E.G., 1971, Buried Precambrian rocks of South Dakota: Geological Society of America Bulletin, v. 82, p. 1411-1420. 2 00 300 Lisenbee, A.L., 1985, Tectonic map of the Black Hills uplift, Montana, Wyoming, and South Dakota: Wyoming Geological Survey MS-13, scale 1:250,000. Martin, J.E., Sawyer, J.F., Fahrenbach, M.D., Tomhave, D.W., and Schulz, L.D., 2004, Geologic map of South Dakota: South Dakota Geological Survey General 2 400 Map 10, scale 1:500,000. 25 3100 00 Minerals and Mining Program, Oil and Gas Section, 2010, Oil and gas database: South Dakota Department of Environment and Natural Resources, http://www.sddenr.net/oil_gas/ [accessed 2005-2009.] 3200 -1 5 3300 ! 0 Petsch, B.C., 1942, The Medicine Butte anticline: South Dakota Geological Survey Report of Investigations 45, 24 p. 6 0 3400 260 4400 Rothrock, E.P., 1936, Logs of some deep wells in western South Dakota (revised edition 1946): South Dakota Geological Survey Report of Investigations 4, 108 p. 2 0 0 <2335 90 28 470 800 0 00 2 00 4 (Revised 1946). 70 46 4900 -1 0 4 Rothrock, E.P., and Robinson, T.W., Jr., 1938, Artesian conditions in west central South Dakota (2d ed.): South Dakota Geological Survey Report of Investigations 26, 38 0 00 5000 2592 5100 <3040 0 3 " 93 p. 000 <3775 5100 <4980 4760 Sanborn Library LLC, 2010, Digital Sanborn maps, 1867-1970: ProQuest LLC, http://sanborn.umi.com/ [accessed 2006-2009.] 3 5200 -1 Schoon, R.A., 1965, Selected formation tops in oil and gas tests in South Dakota drilled before January 1, 1965: South Dakota Geological Survey Circular 35, 66 p. 50 <5030 3 43 0 <4872 <-61 0 00 4 0 _____1968, Selected formation tops in water wells logged by the South Dakota Geological Survey to January 1, 1968: South Dakota Geological Survey Circular 36, 0 3 30 ! 0 7 3600 53 0 0 <3165 28 p. 0 2 4 5224 5 2 2 ! 3 1 ! Sims, P.K., Peterman, Z.E., Hildenbrand, T.G., and Mahan, S., 1991, Precambrian basement map of the Trans-Hudson Orogen and adjacent terranes, northern 4 0 0 0 - 0 4 0 ^ 0 0 - 1 1 4 0 0 9 0 3 3 0 2 Great Plains, U.S.A.: U.S. Geological Survey Miscellaneous Investigations Series Map I-2214, 53 p., 1 map sheet, scale 1: 1,000,000. 0 0 50 0 0 0 2 0 0 5000 0 5 2 5400 5 ^ 2 2 0 Sims, P.K., Saltus, R.W., and Anderson, E.D., 2005, Preliminary Precambrian basement structure map of the continental United States – An interpretation of 51 4 0 4 0 00 4 3 3 ! 2 9 0 3 1 0 <1530 0 0 ! 4 0 0 -8 geologic and aeromagnetic data: U.S. Geological Survey Open-File Report 2005-1029, 31 p. 5500 0 0 3 0 0 <3849 5300 4 6 ! 0 5 0 0 Steece, F.V., 1961, Preliminary map of the Precambrian surface of South Dakota: South Dakota Geological Survey Mineral-Resource Investigation 2, scale 1 in = 17 mi. 5600 0 - 0 4 0 0 3165 1 0 3 30 " 0 - 5700 5 % 0 1 Todd, J.E., 1898, The first and second biennial reports on the geology of South Dakota with accompanying papers: South Dakota Geological Survey Bulletin 2, 139 p. 0 ! ! ! - 1 0 ^ 4466 7 0 5800 361 0 5 ! 67 % <4 0 0 0 2 41 ! 0 0 5 0 <2753 2600 <2528 5 0 #0 20 3 5900 4 0 4590 4 5 8 6 4535 ^ 2700 - 0 0 ! 6 0 0 5806 0 5800 #* <3790 2 0 ^ 3 800 6 5 3 3 29 5900 465 5475 ^ 50 0 00 ! <2246 0 0 32 3168 0 < - 4590 4 4580 0 0 000 5 < 4 7 0 ^ ! 3 0 9 0 8 ^ 0 0 0 5 0 4640 " - ^ 4810 4 4983 " 5075 4100 0 5655 % 455 5310 0 Explanation ^ ^ 5 4200 4300 ^ 5340 4695 0 2 " 0 0 4 0 ^ 4 5 0 - 5900 6003 0 0 0 4 4600 0 0 3 6300 2 0 5115 4810 0 6 7 0 1 0 5 6 3 547 975 0 10 #*% ^ 4 47 0 0 ^ 6 ^ ^ ^ 0 0 6200 5830 0 0 ^ 3 - 2 6000 0 0 30 4 59 5 0 DRILL HOLES 6 % 5475 5260 0 5365 8 1 0 0 5 5

5 0 0 #* 00 ^ ^5145 0

9 0 5 00 00 5080 0 % 8 7 ^ - 5 5 % 5 ^ 1 <5805 55 8 35 5170 00 6400 00 53 0 4339 Data point; number is elevation in feet relative to mean 0 4 0 ! 0 ^ 6680 ^5635 5 9 ^ 6 5 6500 5 0 5 800 ^ ^ 00 4395 0 0 2 4 ! 90 580 547 0 ! sea level. A "less than" symbol (<) indicates elevation is 51 6600 <5605 ! 0 ! 0 0 <970 0 0 5690 7 0 0 550 0 50 <-1240 54 ! ^ 5380 4925 00 <3895 <3530 0 4 00 5291 5441 5100 0 less than the number shown. 55 0 <5500 ^ 5592 ^ ^ 30 5900 ^ ^ <2888 0 5 ! <5750 5 0 0 <5410 4745 0 0 00 00 5 ^ 55 8 0 52 6 55 9 00 4984 ! 0 <2018 <5625 % 0 0 305 5500 00 ! 00 0 5 50 5 51 ! 5600 5 4900 6 Rock Type 7 5654 ^ ^ 1 5000 0 000 0 5558 ^ 0 9 0 5 0 ! 5 5491 0 0 5795 ^ ^ 540 0 ! 00 % ! ^ 5 49 ^ 5775 5655 5515 3 4940 ! Basement not intersected ^ 5492 0 1 550 0 855 0 5667 <5375 5 ^ 4 0 0 % ^ 60 0 <2425 90 3 49 ^ 5 ^ 557 ^ 5255 48 Schist, phyllite, or slate 0 6 0 %2 5310 <4795 00 0 5595 3 90 ! 1 6 0 13 02 1 0 57 56 ^ 5 0 ^ 460 § 0 0 ¨¦ 0 0 395 l 1 5797 ^ % 0 <1 Possible schist, phyllite, or slate 6 0 ^ 5600 ^ % !. <5915 6 5676 ! 5470 5324 4570 1 ^ ^ ^ ! 2 <3570 0 ^ 5518 5045 0 Schist and granite ! 5 ^ ! ! 0 0 4 ^ 59 0 0 5425 0 00 7 3 8 6 <5970 5875 5 0 5120 ^ 0 80 9 ^ 5 30 3 <60 990 Schist and pegmatite 6 0 5 ^ <4245 0 61 4 ! 0 0 0 5965 0 7 4730 ^ 5657 ^ 0 5700 5246 0 4 0 6008 4 0 4713 0 ^ 3 56 40 ^ ^ 4930 X 4 0 <313 Schist and quartzite 0 0 6 0 0 6 % 0 0 ! 0 35 0 7 59 0 4 1 5 0 4 !( 5500 ^ 5378 1 54 5799 ^ ^ 0 Pegmatite 0 5 0 0 5 5049 0 5810 0 0 <56106100 0 4 ^ 5475 % 2 1 0 ! 0 3 !. 0 ^ 0 0 4 <5670 6500 5734 600 5 X Possible pegmatite 8 ! 2 5 4 ^ 0 4 6 5300 4 0 0 5800 0 5 0 0 3 0 6 0 4900 4931 0 4 0 4 1 <5610 ! 0 5900 6 0 7 0 6 ! 2 0 ^ Granite 0 ^ ^ 4 4 4 0 3 0 0 0 430 5 0 0 0 4700 4388 4 6 0 6 0 70 5800 0 <37 3 ^ 0 0 6 0 0 5 0 4200 0 6 4710 !. 0 5876 ^ ^ 5450 3782 Possible granite 5 ^ ^ 9 6 5043 4555 369 4100 5398 4477 4585 <1790 ^ ^ - 1 ! 5 ! ^ ! 5 <5770 70 - Gabbro 0 0 ^ 1 0 0 4266 2 0 1 ! ^ ! ! 5 ^ 5598 4480 0 0 0 #* 0 0 ^ 0 2 5000 4123 3167 Amphibolite 0 5 - 5 6 ^ ^% 1 4 ^ ^ 4400 4 0 5892 05 0 0 43 - #0 0 0 ^ 3851 1 Possible greenstone 5237 < 1 0 ^ 2 0 - 9 ! <363 1 4 ^ 0 3

G ^ %2 6311 3012 0 %2 2 ^ 0 Quartz, quartz vein, or chert <6290 ^ ! ! 6600 5620 5236 4538 1480 % 5663 Quartzite 5910 ^

0 2

6 0 ^ 0 ^ 2 0

0 0 ^ 0 % 7 0 %2 25 5 <63 0 9 #* 5752 ^ 0 0 Possible quartzite

! 6 5 0 2 6 6 0 X 0 Banded iron-formation 5922 N ^ 2 5 4110 6 ^ 0 < " 400 4705 0 6 Basement intersected, rock type unknown 5156 4405 6300 1 ^ ^ <3230 0

^ 0 4782 6600 6130 ! 6

4609 500 5720 4297 -687 Possible basement intersection 6 ! < 4300 ^ ^ ^6245 ! !

^ 4200 3517 1 5 6 I 6500 613 ^ 3586 ^ 3610 0 1 0

6 4100 2 ^ 9 0 6 ^ ^ 0 1 0 1 6035 ^ 0 00 0 7 0 0 0 2 4800 0 1N 6 0 ^ CONTOURS 3 6 1 0 0 0 4 6 55 4457 0 0 5

6 0 6 5960 1 0 0 1 0 0 ^ 0 0 5 0 5 320 1 5995 0 5 0 1200 0 8 273 8 00 3 0 3 58 0 ^ 3892 Number is elevation in feet relative to mean sea level 9 0 0 0 6500 120 0 0 6 6 ^ 2 4 8 5 602 6 117 4 0 3 M 5755 3 0 5298 ^ % 0 0 ^ 0 0 ^ Major; dashed where uncertain 8 ^ 5 ^ 0 000 0 00 2 0 6 7 9 ^ 0 0 0 4 8 0 5 3110 <1722

0 ^ 0 40 3 723 5422 33 0 0 ^ ^ 6285 ^5 ^4300 ^3065 0 Depression, major; dashed where uncertain 5530 5910 0 2 0 9 5 ^ 6065 0 5480 <970 3890 0 4 6010 57 0 ^ 0 3 ^ 3060 4 ^ 0 5 470 7 610 0 4 Minor; dashed where uncertain 5 5 2300 ! 0 5 ^ ^ 0

^ 5 0 6208 5 ^ 0 0 6 < 320 462 90 3 0 6 ^^ ^ 31 0 0 ^ ^ ^ 4834 0 200 0 6600 ^ 4456 460 2 Depression, minor; dashed where uncertain 5180 5115 0 % - ^ ^ ^ 004 9 6700 4 0 O ^ ^ ^ 5 ! ^ 0 3398 0 2 4681 437 6350 ^ 0 5 0 ^ 391 - 4 - 0 3 0 ^ 8 3 6 6442 0 2 ! - 0 6 ^ 0 6 5 4455 2100 5 - 364 0 0 0 8 5 0 1 1S 5 0 5 0 5 ^ ^ 76 8 - 3 0 4 45 0 1 4507 3 0 7 !( 6 6 0 37 4400 0 0 62 ! 0 0 0 0 5 <311 0 0 - 0 0 4 8 5 ^ - ^ 1 0 ^ 6 761 7 BASE DATA 7 9 4 0 6 ^ 680 0 0 4 3788 0 0 0 0 6 6 5 1 9 0 0 0 0 9 0 0 0 0 4 ^ 3 - 0 0 0 ^ 9 ^ - 0 2 0 4 4 6600 0 5500 5202 0 ^ 0 0 0 5087 0 0 0 0 0 6 0 4 0 350 2 83 0 4770 4 Y 65 3 9 5 3 4 0 7 0 5 0 0 5 6 6 6900 4 0 1 0 4800 0 0 5 0 0 0 ^ 5 0 0 0 ^ 0 Area of Precambrian outcrop in the Black Hills 0 6 0 0 4 3 0 5285 4180 4 8 ^ 5 0 0 6 0 8 0 8 ^ 0 0 4 0 6 3 0 4 6 4190 0 ^ ^ 6 6

0 6482 5001 3 0 5137 0 7 0 0 0 ^ 3 ^ 0 3 0 0 320 680 #* 290 5 6 5 3 <3 <1645 0 City 4 7 5 6 591 0 6620 6 3 0 0 2 0 ^ ^ ! 6700 ^ 4339 0 ^ 0 2 ! ! 5204 ! 3 5995 1 County W < ! 3 6015 3840 0 3 15 ^ 6900 66 ^ 0 0 0 3465 % 0 0 ^ ^ 6817 680 7 690 ^ ^ 3110 3090 0 6 6 0 !. 3 6 ^ 342 90 00 ^ 3760 § 3555 <2850 ¨¦ Interstate Highway <6327 ^ ^ ! 3930 6 ^ 5 0 ^ 4530 ! 0 4670 ! 0 15 0 !( <33 4175 ^ 4 5885 ! 6 5110 !( ! 3400 0 ^ ^ 85 ^ <3378 0 !( 47 3N 3 5 6 3260 6 2 < ! 2 ^ 0 !( 0 6485 6315 134 0 0 ! ! Township-Range grid 0 6 594 !( ! <2857 5545 2E 6 6065 3 3718 0 ^ ^ ^ <2673 0 3 0 ^ 467 0 1 ! ^ ^ 3 ! 4 0 5925 1 0 ^5842 80 4419 ! 533 63 4928 6300 ^ 58 5 ^ <3829 6200 00 <2202 6010 !( <3085 ^ 6025 5835 6055 ^ <6085 770 <6125 ^ 5 % !( ! 0 0 5583 !( 5410 0 0 0 5 3 5867 6001 ^ 5967 ^ 1 1 6100 ^ l 0 5343 6400 7 5335 !. 0 5645 5 5412 ! 0 <4012 6112 ^ 5475 !( 0 1 ^ 5298 20 1 ! ^ 1 00 3 6118 % 6060 5742 5595 5290 9 ^ 5601 0 0 5956 <1421 0 <3452 0 ^ 5!(400 ! 0 0 3 5349 1 0 ^ <3180 <2690 8 6 ^ 5260 ^ ^ 6136 5940 ^ ^ ^ ^ ^ 6232 5 5110 <2625 30 5335 ^ ^ 0 ^ 5046 5300 ! ! 6068 0 ^ ^ ^ 0 5436

0 5620 0 6 5400 ! 5515 % 5540 ^ ^ 5051 0 ^ ^ 5457 ^ 7 ^ 5465 ^ % 5273 % ^ 5620 ^ ^ 5397 5048 !( 0 ! 5401 5500 5497 ^ 0 ! % <5240 0 <4558 ^ ! 0 4 ! 5554 ! 5174 6 ^ 5600 5605 4800 995 5401 5434 4760 <4 ^ 5510^ ^ ! <-629 5 435 4700 05 5500 5 ! 57 2 5499 ! 0 ^ 0 4505 0 !( 4600 < ^ ^ ^ ^ ^ 0 450 5350 % 5 0 5180 5381 ^ ^ 5570 ^ 3830 ^ 0 4 22 440 7 37 0 0 0 5495 543 5388 ^ 1 0 43 ! 0 4 4 0 5475 ^ 1

0 - 1 20 ^ ^3 5435 0 0 0 524 0 0 0 5 5735 4 0 4 8 3 8 405 0 5328 5218 4590 - 4 3 <4 0 0 9 ^ 0 3974 0 0 ^ ^ 4 0 !( ! 0 ^ 0 0 53 5408 6 0 ^ 0 1 0 6 0 !( 0 - 0 3 0 ^ 5266 4 0 3900 ! 8 4 0 0 ! 0 0 9 ! 0 5534 289 0 0 - 226 5 2 0 0 5 1 0 ^ 0 5 0 - 0 <3455 3 ^ 5 <2955 0 0 4923 0 ^ ! <257 0 2 2 7 5675 7 2665 - - 0 0 ^ < 1 ^ 0 0 0 5637 ^ ! 0 - 0 ! 150 <3460 0 5 3380 3 7 < 0 539 0 0 - 3 0 5374 ! 0 " 9 1 6 7 ^ 0 4 38 0 5 <2995 -

0 1

4 ^ - 0 - 4 4850 90 60 ^ 50 ^ 0 0 0 ! ! <2268 !( 4 5 <3353 280 ^ 6 4 0 <3 ! 0 4542 <4530 0 0 <3253 ! !( 4 5289 4789 4 0 0 5100 ^ 4 2 0 ! 5020 70 4 4 <3281 0 0 30 ! 8 5140 0 0 2 <4830 ^ 4 0 ! 4917 9 0 0 3 <2930 4132 0 0 0 " 0 0 4350 ! 7 ^ 4800 <3277 1 0 ^ 2 2 509 ^ ^ 0 " 4526 0 0 ! 5100 ! 0 0 9 5 9 0 1 ^ 4855 2 0 0 ^ <3045 2 0 0 ^ 408 ! 0 0 " 4 2 7 500 0 2 48 0 1 3 4654 00 6 5 !( ! 2 0 0 <2973 ! ^ 0 0 0 8 0 <4454 4319 1 6 1 <1538 ! 4758 ^ ! 0 ! 4 ! 00 0 4525 4910 5 5 3 ! 0 ^ ^ 2 2 0 4700 4645 4737 3 4662 ! 0 <2668 4 <4345 4630 40 0 <4644 496 2 ! 0 4322 <3 ! 3005 8 9E <4323 5 6 < 7 1E 2 3809 3 ! 4 0 < 0 4148 6 3024 ! ! 4 ^ <2173 ! <1422 3 <3545 ! ! 3 ! <4090 0 0 3887 00 ! 0 3932 4 ^ ! <4327 32 <3175 ! 00 ! 2 3685 80 ! 4 ! <25 0 3 3619 ! 6 2 0 2 10 % <2475 1 1 5 0 " 0 6 0 2 0 0 4 0 0 2 0 0 0 5 <242 0 364 ! ! 1 0 0 638 ! 0 728 2 2 <3 5 ! <2 2 3 7 !. 3 ! 0 0 2 0 <333 1 0 0 0 2 9 3 0 7 0 8 0 0 <3500 3675 2308 0 0 0 0 2 00 0 0 4 2 0 6 0 <1738 1 1 1 0 4 1 0 <3297 0 1 8 0 5 0 ! 0 0 039 0 1 <3 0 9 0 8 1 0 3 0 0 3 0 1 0 0 0 <3632 0 0 0 ! 1 9 ! ! 1 9 0 1 <2288 0 0 2 0 0 60 7 0 ! <3298 0 0 0 0 1 0 <1350 0 0 ^ 1 8 ! 0 <2644 3445 0 11 0 ! 0 0 0 500 7 ! 0 0 6 Scale 1:500,000 7 400 ! <2815 <478 <2125 ! Upper metagraywacke Metabasalt ! <2635 Xgwu Xb1 300 ^ Legend (Lower Proterozoic) (Lower Proterozoic) 3060 200

Xgwl Lower metagraywacke Xd Metamorphosed dolomite (Lower Proterozoic) (Lower Proterozoic) 100 !

Phanerozoic rocks, surficial Xms Metamorphosed tuffaceous shale Xif Iron-formation deposits, and lakes (Lower Proterozoic) (Lower Proterozoic) 0 <1927 Metamorphosed black shale Xh Harney Peak Granite Xbs Xc Metaconglomerate (Lower Proterozoic) (Lower Proterozoic) (Lower Proterozoic) ! 0 Metaconglomerate and 8 Metamorphosed shale Metamorphosed carbonaceous shale Xsh Xsc2 Xcq metaquartzite ! <1612 ! <1620 (Lower Proterozoic) (Lower Proterozoic) <960 0 (Lower Proterozoic) 0 2 1 - Pegmatite Metabasalt Metaquartzite Xb2 Xq XWp (Lower Proterozoic or ! (Lower Proterozoic) (Lower Proterozoic) <-1178 Upper Archean?)

! Metagraywacke Metabasalt 200 Metamorphosed conglomerate < Xgw (Lower Proterozoic) Xcg XWb (Lower Proterozoic) (Lower Proterozoic or <102 Differentiated where possible Upper Archean?) ! ! ! 145 <613 0 0

0 0 Metagraywacke 5 Metagraywacke unit 3 Metamorphosed siltstone 1 Xgw3 Xsi XWgw 1 (Lower Proterozoic or - Upper Xgw (Lower Proterozoic) 0 Upper Archean?) 0 0 1 0 - 4 ! 0 0 Metagraywacke unit 2 Metagabbro Granite 0 0 <-978 Xgw2 Xmg Wgr 2 2 0 - 0 0 Middle Xgw (Lower Proterozoic) (Upper Archean) 9 -1 0 4 0 3 - 0 0 0 0 0 3 Older metasedimentary 1 - 0 Metamorphosed carbonaceous shale Xgw1 Metagraywacke unit 1 Xsc1 Wos 0 ! rocks 6 (Lower Proterozoic) - <-1192 Lower Xgw (Upper Archean) -200 <958 0 ! 0 0

0 0

5 1 - - Precambrian rock types and major faults within the enclosed Precambrian outcrop area of the Black Hills, South Dakota. Base data defined in Explanation. Figure is modified from Martin and others (2004).

!<-200 ! 0

! <479 0

7 -255 - 0 0 00 -3 -8 -10 00 ACKNOWLEDGEMENTS 0 0 ! 9 The author thanks Dan Costello (Geological Survey Program, Department of Environment and Natural Resources) <-257 - 0 10 0 for assistance in the map layout. This map was greatly improved through review and discussions with the following 1 1 - people: Val Chandler (Minnesota Geological Survey), Ray Anderson, Bill Bunker, Caroline Davis, and David Pals ! 365 ! (Iowa Geologic and Water Survey), Edward Duke, Alvis Lisenbee, Colin Paterson, Jack Redden, Bill Roggenthen, - 4 <-914 0 and Mike Terry (South Dakota School of Mines & Technology), Mark Fahrenbach (Geological Survey Program) and 0 ! Fred Steece (Minerals and Mining Program, Department of Environment and Natural Resources). Thanks is also <-974 given Layne Schulz, Derric Iles (Geological Survey Program), Alvis Lisenbee, and Dan Costello for reviewing data. ! <-143 There were several sources of unpublished information that were used in the development of this map which are ! acknowledged below. The sources were (1) a database of down-hole geophysical logs developed by the <-277 0 Geological Survey Program, (2) personal files of J.P. Gries to which access was provided by the South Dakota School of Mines & Technology, (3) files of the Geological Survey Program containing geochemical data compiled ! <349 by R.A. Schoon and a May 1994 letter from R.A. Schoon to “Placer Dome, U.S.” listing selected test holes and 0 0 1 -1 wells intersecting the Precambrian surface, (4) compilations in 1952 and 1963 by F.V. Steece of test holes and

11 ! wells intersecting the Precambrian surface, and (5) internal databases developed by the Water Rights Program, <-981 Department of Environment and Natural Resources, containing information on a statewide network of observation 0 0 2 wells, water-right permits, and well-completion reports. -1 -5 00 0 234 ! - 0 <- 600 3 -1

! -266 0 0 ! 4 ! 1 -570 - -1325 ! <-350 0 12S -70 <-648 ! : Scale 1:150,000

0 3 6 9 12 Miles -800 Inset Location 0 4 8 12 16 N E B R A S K A Kilometers Black Hills Inset Contour interval is 100 feet. Contour datum is mean sea level. -900 Map Projection: North American Datum 1927 Lambert Conformal Conic -1000

The Geological Survey Program, Department of Environment and Natural Resources, engages in an ongoing data collection and interpretation process. An outcome of that process is to reflect those interpretations on maps such as this one. Reasonable efforts have been made to ensure that this map accurately reflects the source data used in its preparation. This map is date specific. As additional data become available, geologic interpretations may be revised and the map may be updated by the Geological Survey Program. This map should not be enlarged or otherwise used in an attempt to interpret more detail than can be seen at the 1:150,000 scale.