Reger, R.D., and Burns, P.A.C., 2013, Surficial-geologic map of the Livengood area, central Alaska: Report of Investigation RI 2013-2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, AK, USA.Online Links:
This is a vector data set.
Planar coordinates are encoded using coordinate pair
Abscissae (x-coordinates) are specified to the nearest 0.000001
Ordinates (y-coordinates) are specified to the nearest 0.000001
Planar coordinates are specified in meters
The horizontal datum used is North American Datum of 1927.
The ellipsoid used is North American Datum of 1927.
The semi-major axis of the ellipsoid used is 6378206.4.
The flattening of the ellipsoid used is 1/294.9786982.
Alpha-numeric characters that uniquely identify each polygon. The general form: publication number of the report followed by an auto-generated numeric value.
| Value | Definition |
|---|---|
| Qelx | FROZEN LOESS WITH CONSIDERABLE GROUND ICE-On north-, east-, and west-facing upper and middle slopes, a blanket 1.5 to 14 m thick of massive to laminated, very well sorted eolian silt typically contains soil horizons and organic layers (Kreig and Reger, 1982, plate12). Transitional on middle slopes with retransported silt and lowland loess covering lower slopes. Thickness increases from Livengood northward toward the main source of eolian sediments in the Yukon River lowland (Williams, 1962; Brown and Kreig, 1983; Muhs and Budhan, 2006). Perennially frozen to within ≤1 m of ground surface and locally contains massive ground ice (Kreig and Reger, 1982, plate 12, table 18). Dissected by dendritic, pinnate gullies with convex walls and narrow floors (Kreig and Reger, 1982, plate 12, fig. 8). Tree cover is dominantly black spruce forest mixed with scattered paper birch; large black spruce trees and willow shrubs follow drainages, where perennially frozen ground is deeper. Includes unit Qe of Athey and others (2004a). |
| b' | THINLY COVERED BEDROCK-Subcrops covered by less than 0.9 m of loess and frost-rived and weathered bedrock. Bedrock structures visible through thin veneer of surficial debris. |
| Qer | RETRANSPORTED SILT AND LOWLAND LOESS-Chiefly massive to laminated organic silt and silt with trace to some fine sand, lenses and tongues of locally derived gravel, and scattered to numerous angular rock fragments (particularly in upper valleys of small, ephemeral streams). Deposited primarily by hyperconcentrated flows (Tuck, 1940; Taber, 1953, 1958; Costa, 1988; Fraser and Burn, 1997) draining weathered bedrock slopes thinly covered by upland silt (loess) and generated by thawing ice-rich perma-frost or during brief, intense summer rainstorms. Complexly mixed with gelifluction and debris-flow deposits in upper stream drainages and primary airfall loess in lowland sites (Kreig and Reger, 1982). Transitional on middle slopes with frozen loess containing considerable ground ice. Fluvial processes >> colluvial processes. Lowland surfaces fairly smooth with scattered open-system pingos and local thermokarst pits, ponds, and lakes. Erosion on slopes by ephemeral drainages produces subparallel gullies separated by linear ridges and ellipsoidal and triangular remnants that are generally shallowly frozen, except beneath well developed aspen and birch on upper south-facing aspects (Kreig and Reger, 1982, plate 11). May be subject to seasonal stream and slope icings. Locally contains fossil remains of late Pleistocene mammals. Continuously to discontinuously frozen with moderate to high ice content; locally contains considerable massive ground ice (Kreig and Reger, 1982, plate 12) (yedoma of Kanevskiy and others, 2011). Includes unit cf of Waythomas and others (1984) and units Qcfl, Qcfu, and Qe-c of Athey and others (2004a). |
| Qcf | MIXED COLLUVIUM AND ALLUVIUM-Primarily elongate, massive to poorly stratified, generally inorganic silt (loess) mixed with locally auriferous, sandy, angular to subangular, pebble and cobble gravels with scattered boulders derived from weathered bedrock uplands. Deposited in the upper drainages of small tributaries by debris flows and hyperconcentrated flows produced during brief, intense, local summer storms. Grades downvalley into retransported silt and lowland loess and stream terraces at the margins of lowlands. Colluvial processes > fluvial processes. Surface slightly uneven. Discontinuously to continuously frozen with low to moderate ice contents. |
| b | EXPOSED BEDROCK-Outcrop and rubble crop that show no evidence of downslope displacement. |
| Qel | LOESS-A blanket generally less than 1 m thick of massive, very well sorted eolian silt with thin, local, oxidized weathering profiles and traces of organic material covers ridge crests and upper south-facing slopes. Small, frost-jacked angular rock fragments are locally present close to underlying weathered bedrock. Sections exhibit lamination parallel to the ground surface resulting from the formation of thin, ground-ice lenses during seasonal freezing. Permafrost is absent. Dissected by concave-floored gullies separated by parallel to subparallel, rounded, low ridges where loess is thicker (Kreig and Reger, 1982, plate 11, plate 12, fig. 8). Tree cover is a forest of closely spaced, mixed paper birch and white or black spruce or pure stands of paper birch, except on steep, dry, south-facing slopes where stands of quaking aspen dominate a woodland of scattered, mixed white birch and white spruce. Includes unit Qe of Athey and others (2004a). |
| Qat | TERRACE ALLUVIUM-Chiefly moderately to well-sorted pebble and cobble gravels with some silty sand and local silt lenses no longer flooded by the streams that deposited the alluvium, which is locally auriferous. Covered by 1 to 2 m of overbank silts and sands. Locally covered by several meters of retransported silt and lowland loess. May include several levels. Locally subject to inundation by seasonal slope and stream icings. Continuously to discontinuously frozen with low to moderate ice contents. |
| Qa | UNDIFFERENTIATED ALLUVIUM-Chiefly moderately to well-sorted, stratified, polymictic pebble, cobble, and boulder gravel, sand, and silt comprising channel and overbank deposits of generally small streams. Clasts of the local bedrock are rounded to subangular. Locally auriferous. Unfrozen to discontinuously frozen with low to moderate ice contents. |
| Qcl | LANDSLIDE DEPOSITS-Matrix-supported silty diamicton with numerous angular to subangular pebbles, cobbles, and boulders of Amy Creek dolomite and limestone and Amy Creek siliceous mudstone and chert east of lower Amy Creek. Previously mapped as debris fan and reworked loess by Athey and others (2004a,b). Slide in the vicinity of lower Amy Creek measures l.37 km long by up to 1.1 km wide, and the 3.5-m-thick slide deposit is composed of three 0.8- to 1.5-m-thick, very pale brown (10YR8/3) to reddish yellow (7.5YR7/6), massive, horizontal beds that could indicate a history of three failure events. In that section, the slide overlies thrust-faulted Amy Creek dolomite and limestone bedrock (Athey and others, 2004a,b) that is altered to dark yellowish brown (10YR6/8) to white (10YR8/1) and contains lenses of rotated, angular fragments of dark gray Amy Creek siliceous mudstone and chert. The slide is overlain by ~1.3 m of artificially emplaced silty mining debris. The slide on the western flank of the bedrock ridge between Lucky and Goldstream creeks is deeply dissected, and the slide headwall at ~530 m (~1,750 ft) elevation is subdued, indicating the antiquity of the deposit. Discontinuously frozen with low to moderate ice contents. |
| water | water |
| Qh | PLACER TAILINGS AND ARTIFICIAL FILLS-Chiefly gravel mixed with angular to subangular rock rubble, sand, and silt in placer-mine tailings, ditches, active surface-mine pits, and borrow pits for road construction or heterogeneous fine-grained excavated overburden and fillings of siltation ponds. Extents determined on 1978 and 1986 aerial photography, except in western Livengood Creek area, determined on 2001 aerial photography. Includes fluvial deposits in valley bottoms and fluvial-colluvial sediments in upper drainages that were mined for placers (Mertie, 1918; 1937; Cobb, 1973; Karl and others, 1988). |
| Qs | SWAMP DEPOSIT-Elongate deposit of silt and organic material in impoundment basin behind Hess Creek dam, which was filled to seasonally supply water for mining purposes until 1984 and drained in winter to allow embankments and related structures to refreeze (Brown and Kreig, 1983). A photograph taken on 07/22/2011 during an aerial survey by DNR personnel revealed that the impoundment basin is drained. |
| Qfb | BENCH ALLUVIUM-Locally auriferous, oxidized alluvial gravels that are present on bedrock benches well above local streams as a result of a long and complex history of stream piracy and tectonic deformation in the Livengood area (Mertie, 1918, 1937; Cobb, 1973; Athey and Craw, 2004). On Livengood Bench, 3 to 15 m of crudely bedded, moderately to well-sorted, subrounded, oxidized, polymictic pebble and cobble gravels with some sand; contains organic and inorganic silt lenses up to 8 m long and 0.5 m thick with scattered fossilized wood fragments and stumps up to 0.3 m in diameter. One silt lens contained late Miocene to Pliocene pollen (Karl and others, 1988). The bench gravels are 15 to 25 m above the modern drainage and are overlain by 15 to 40 m of frozen, retransported silt and lowland loess. The age of the thick, fine-grained overburden is bracketed by the ages of two samples of wood from the base of the silt, which are dated at 28,470 +/- 600 RC yr B.P. (Beta-6026) and 29,460 +/- 480 RC yr. B.P. (Beta-6025), and a single wood date from 2 m below the top of the exposed frozen silt that dated 26,410 +/- 540 RC yr. B.P. (Beta-6027) (Waythomas and others, 1984). Continuously to discontinuously frozen with low to moderate ice contents. |
| Value | Definition |
|---|---|
| certain | Indicates that the author has sufficient observational and/or other supporting data to be reasonably confident in the scientific credibility of the interpretation of the feature. The level of certainty is specific to the map scale. |
| Formal codeset | |
|---|---|
| Codeset Name: | FGDCGeoAge font |
| Codeset Source: | Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates. |
| Formal codeset | |
|---|---|
| Codeset Name: | MapUnit |
| Codeset Source: | MapUnit field of this dataset |
| Value | Definition |
|---|---|
| 1230 | CMYK value - C:13%, M:20%, Y:30%, K:0% |
| 0001 | CMYK value - C:0%, M:0%, Y:0%, K:13% |
| 0A20 | CMYK value - C:0%, M:8%, Y:20%, K:0% |
| 2360 | CMYK value - C:20%, M:30%, Y:60%, K:0% |
| 0003 | CMYK value - C:0%, M:0%, Y:0%, K:30% |
| A250 | CMYK value - C:8%, M:20%, Y:50%, K:0% |
| 11X0 | CMYK value - C:13%, M:13%, Y:100%, K:0% |
| 0050 | CMYK value - C:0%, M:0%, Y:50%, K:0% |
| A350 | CMYK value - C:8%, M:30%, Y:50%, K:0% |
| 41A0 | CMYK value - C:40%, M:13%, Y:8%, K:0% |
| 2460 | CMYK value - C:20%, M:40%, Y:60%, K:0% |
| 33X0 | CMYK value - C:30%, M:30%, Y:100%, K:0% |
| 0020 | CMYK value - C:0%, M:0%, Y:20%, K:0% |
Alpha-numeric characters that uniquely identify each line. The general form: publication number of the report followed by an auto-generated numeric value.
| Value | Definition |
|---|---|
| map boundary | Line that delineates and defines the extent of geographic and geologic data provided by this report. |
| contact | Surface expression of a plane or irregular surface that separates two distinct types or ages of rock. |
| waterline | Line that delineates a boundary between water and land. |
| Value | Definition |
|---|---|
| N | The feature IS NOT covered by an overlying map unit. |
| Value | Definition |
|---|---|
| certain | Indicates that the author has sufficient observational and/or other supporting data to be reasonably confident in the scientific credibility of the interpretation of the feature. The level of certainty is specific to the map scale. |
| Value | Definition |
|---|---|
| certain | Indicates that the author has sufficient observational and/or other supporting data to be reasonably confident in the scientific credibility of the interpretation of the feature. The level of certainty is specific to the map scale. |
| Value | Definition |
|---|---|
| -9 | The author has not provided a numeric measurement of the likely error range of this feature. |
| Formal codeset | |
|---|---|
| Codeset Name: | FGDC Digital Cartographic Standard for Geologic Map Symbolization; Appendix A. Geologic map symbols, colors, and patterns, "REF NO" field |
| Codeset Source: | Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates. |
We thank the staff of Talon Gold Livengood for permission to enter their busy mining properties and for providing logistical support. Doug Baker kindly allowed access to his placer properties on upper Livengood Bench. The friendly hospitality of Larry Nelson, who let us camp at his placer mine, was greatly appreciated. Several field colleagues, including Jen Athey, Rainer Newberry, Dave Szumigala, and Melanie Werdon, mapped bedrock in the Livengood area and provided data that better delineated outcrops and subcrops in our surficial geology map. Tyler Cole, U.S. Bureau of Land Management in Fairbanks, efficiently provided GIS coverage of the recently mined area on upper Livengood Bench, which is incorporated into our map. Assistance in the field during 2003 was provided by Carrie Browne and Lauren Staft of DGGS. We welcome the insightful comments made in 2003 at the terminus of the ancient, large landslide on lower Amy Creek by Florence Weber (USGS) and De Anne Stevens (DGGS). Review comments by Diana Solie and Trent Hubbard that helped complete and clarify this report are greatly appreciated. Funding was provided to DGGS for this work by the State of Alaska and the U.S. Geological Survey (National Co-operative Geologic Mapping Program, STATEMAP award number 03HQAG0055).
(907)451-5029 (voice)
dggsgis@alaska.gov
The objective of this project was to produce 1:50,000-scale geologic maps of the area to foster a better understanding of the surficial geology, and the mineral and engineering-material resource potential of the Livengood area. This publication presents the surficial geology of the map area.
Athey, J.E., and Craw, P.A., 2004, Geologic maps of the Livengood SW C-3 and SE C-4 quadrangles, Tolovana mining district, Alaska: Preliminary Interpretive Report PIR 2004-3, Alaska Division of Geological & Geophysical Surveys, Fairbanks, AK, USA.Online Links:
Athey, J.E., Werdon, M.B., Newberry, R.J., Szumigala, D.J., Craw, P.A., and Hicks, S.A., 2004, Geologic map of the Livengood SW C-3 and SE C-4 quadrangles, Tolovana mining district, Alaska: Preliminary Interpretive Report PIR 2004-3A, Alaska Division of Geological & Geophysical Surveys, Fairbanks, AK, USA.Online Links:
Athey, J.E., Szumigala, D.J., Newberry, R.J., Werdon, M.B., and Hicks, S.A., 2004, Bedrock geologic map of the Livengood SW C-3 and SE C-4 quadrangles, Tolovana mining district, Alaska: Preliminary Interpretive Report PIR 2004-3B, Alaska Division of Geological & Geophysical Surveys, Fairbanks, AK, USA.Online Links:
Soller, D.R., 2009, Digital Mapping Techniques '09-Workshop Proceedings, Morgantown, West Virginia, May 10-13, 2009: Open-File Report OF 2010-1335, U.S. Geological Survey, Fairbanks, AK, USA.Online Links:
Data sources used in this process:
Certainty in identification of the map units varies due to the scale and interpretive nature of the mapping. The geologic unit interpretations and boundaries presented in this map result from interpretation of 1:63,360-scale, false-color infrared aerial photographs taken in August 1978 and August 19861, investigative traverses throughout the map area, aerial reconnaissance via helicopter, and examination of river exposures. Tailings were mapped in the western Livengood Creek area using 1:6,000-scale aerial photographs taken in 2001. The air-photo interpretations were adjusted as needed to be consistent with bedrock exposures identified by Athey and others (2004a, b). Per NCGMP09 specifications, the authors have assigned a confidence value to each polygon and line segment to indicate their degree of confidence in the positioning and identification of the element at the mapped scale. This map has received two technical reviews by scientists familiar with the subject matter. The authors incorporated the reviewer's suggestions into the final draft.
Surficial mappers recorded observations on 1:63,360 scale (nominal) color-infrared aerial photographs (with the exception of the western Livengood Creek area) and 1:63,360 scale USGS topographic base maps. The authors believe the total horizontal accuracy of the mapped surficial-geologic contacts is on the order of 25 m or better, with somewhat lesser accuracy expected in areas of rugged relief. Waterlines and waterbody polygons were entirely derived from topographic base maps, consequently it is possible that the mapped location and extent of these features may differ from modern ground conditions. Per NCGMP09 specifications, the authors have assigned a confidence value to each polygon and line record to indicate their degree of confidence in the positioning and identification of the element at the mapped scale. This map has received two technical reviews by scientists familiar with the subject matter. The authors incorporated the reviewer's suggestions into the final draft.
This dataset provides shapefiles that display information about the mapped and interpreted surficial geologic deposits throughout the map area that are traceable on air photos at a scale of approximately 1:63,360 and/or in the field. No analytical tests were conducted for this report.
Polygon topology was implemented per NCGMP09 specifications (polygons must not overlap, polygons must not have gaps, boundaries must be overlain by lines in ContactsAndFaults). All polygon features were topologically validated using ArcGIS for Desktop prior to export to shapefile format.
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- Access_Constraints:
- This report, map, and/or dataset is available directly from the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (see contact information below).
- Use_Constraints:
- Any hard copies or published datasets utilizing these datasets shall clearly indicate their source. If the user has modified the data in any way, the user is obligated to describe the types of modifications the user has made. The user specifically agrees not to misrepresent these datasets, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys. The State of Alaska makes no express or implied warranties (including warranties for 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 Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.
(907)451-5020 (voice)
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RI 2013-2
The State of Alaska makes no expressed or implied warranties (including warranties for 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 Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.
DGGS publications are available as free online downloads or you may purchase paper hard-copies or digital files on CD/DVD or other digital storage media by mail, phone, fax, or email from the DGGS Fairbanks office. To purchase this or other printed reports and maps, contact DGGS by phone (907-451-5020), e-mail (dggspubs@alaska.gov), or fax (907-451-5050). Payment accepted: Cash, check, money order, VISA, or MasterCard. Turnaround time is 1-2 weeks unless special arrangements are made and an express fee is paid. Shipping charge will be the actual cost of postage and will be added to the total amount due. Contact us for the exact shipping amount.
| Data format: | Shapefiles |
|---|---|
| Network links: |
<http://dx.doi.org/10.14509/25179> |
(907)451-5020 (voice)