Gregersen, L.S. Shellenbaum, D.P. 2016 report and digital data Report of Investigation RI 2016-4 Fairbanks, Alaska, United States Alaska Division of Geological & Geophysical Surveys 1 sheet, scale 1:500,000. http://dx.doi.org/10.14509/29658 This map shows the subcrop pattern of the Mesozoic rock units present at the top Mesozoic unconformity (also commonly referred to as the base Tertiary unconformity) in Cook Inlet basin, Alaska. The subcrop is projected onto the top Mesozoic unconformity depth surface of Cook Inlet basin, Alaska, published by Shellenbaum and others (2010). Publicly available geologic and geophysical data from multiple sources were collected, interpreted, and integrated into the subcrop map. Formation picks at the top Mesozoic unconformity were determined for 109 wells. Mesozoic horizons from two regional marine two-dimensional (2-D) seismic datasets (approximately 3,300 miles) were interpreted. Eight map units were established for the Mesozoic subcrop map: Kaguyak-Matanuska Formations, undivided; Naknek Formation; Chinitna Formation-Tuxedni Group, undivided; Talkeetna Formation; Talkeetna-Border Ranges ultramafic and mafic complex (BRUMC), undivided; Pogibshi-Port Graham formations, undivided; plutonic rocks, undivided; and metamorphic rocks, undivided. This map was prepared as part of a multi-year effort by the Alaska Department of Natural Resources. Oil in Cook Inlet basin is primarily sourced out of the Middle Jurassic Tuxedni Group, thus the subcrop trends of the Middle Jurassic oil source rock and other potential Mesozoic-age reservoirs are an important consideration in oil exploration in the inlet. This map was prepared as part of a multi-year effort by the Alaska Department of Natural Resources to provide the public with the most accurate information possible on the geologic framework of this economically important area. >border: A polygon that encompasses the maximum geographic extent of the data observations >SubCropDepthContours: Lines that record depth to the top Mesozoic (base Tertiary) unconformity surface in the Cook Inlet Basin. Depth is measured to top of Mesozoic unconformity in feet below sea level. Contour interval is 1000 ft. The structural surface onto which the subcrop map is projected is taken directly from the top Mesozoic unconformity depth map published by Shellenbaum and others (2010). >SubCropFaults: Lines that record faults that bound map units and dangling faults, modified NCGMP09 format. >SubCropMapUnitContacts: Lines that record map unit contacts and degree of certainty, modified NCGMP09 format. >SubCropMapUnitPolys: Polygons that record the distribution of interpreted geologic units, modified NCGMP09 format. 2010 2016 publication date complete None planned -153.101740 -148.939167 61.842144 59.186514 ISO 19115 Topic Category geoscientificInformation Alaska Division of Geological & Geophysical Surveys Bedrock Geologic Map Bedrock Geology Bibliography Biostratigraphy Core Logs Correlation Depth Interpretation Drill Logs Drilling Energy Energy Resources Folds Forearc Basin Geologic Geologic Map Geology Geophysical Logs Geophysics Gis Hydrocarbon Hydrocarbon Potential Igneous Rocks Inoceramus Interpretation Metamorphic Rocks Oil Basins Oil and Gas Oil and Gas Basin Palynology Petroleum Petroleum Basin Study Reservoir Resources Rock Units Sedimentary Rocks Seismic Interpretation Source Rock Stratigraphy Strike-Slip Structural Geology Structure Structure Contours Structure Map Subsurface Surface Thrust Unconformity Volcanic Rocks Well Logs Alaska Division of Geological & Geophysical Surveys Anchorage Anchorage Quadrangle Cook Inlet Cook Inlet Basin Homer Iliamna Quadrangle Iniskin Bay Kenai Kenai Peninsula Kenai Quadrangle Lake Clark Quadrangle Matanuska River Matanuska Valley Mount Katmai Quadrangle Palmer Port Graham Saddle Mountain Seldovia Seward Seward Quadrangle Southcentral Alaska Susitna River Talkeetna Mountains Quadrangle Talkeetna Quadrangle Tuxedni Bay Tyonek Tyonek Quadrangle Wasilla Alaska Division of Geological & Geophysical Surveys Border Ranges Fault Bruin Bay Fault Castle Mountain Fault Chinitna Formation Chugach Terrane Herendeen Formation Kaguyak Formation Kamishak Formation Lake Clark Fault Matanuska Formation McHugh Complex Naknek Formation Peninsula Terrane Surficial Deposits Talkeetna Arc Talkeetna Formation Tuxedni Group Uyak Complex Valdez Group Walker, J.D., Geissman, J.W., Bowring, S.A, and Babcock, L.E., comp., 2012, Geologic Time Scale v. 4.0: Geological Society of America Carboniferous Cretaceous Early Cretaceous Early Jurassic Early Triassic Eocene Jurassic Late Cretaceous Late Jurassic Late Triassic Mesozoic Middle Jurassic Middle Triassic Miocene Oligocene Paleocene Permian Pleistocene Pliocene Tertiary Triassic 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). 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. Alaska Division of Geological & Geophysical Surveys GIS Manager mailing and physical

3354 College Rd

Fairbanks AK 99709-3707 USA 907-451-5020 dggsgis@alaska.gov 8 am to 4:30 pm, Monday through Friday, except State holidays The authors gratefully acknowledge Spectrum Geo and Seitel, Inc., for authorizing the use of CI88 and CI89 Cook Inlet marine speculative 2-D seismic survey in the construction of this map. The authors also gratefully acknowledge WesternGeco and the U.S. Geological Survey for providing the seismic reflection data for the purpose of this research. Significant improvements were made to the map thanks to feedback and discussions with David LePain, Rick Stanley, Paul Decker, Dan Seamount, Art Saltmarsh, Rick Saltus, Dwight Bradley, Laurel Burns, Robert Blodgett, Al Hunter, Bob Gillis, Marwan Wartes, Trystan Herriott, Robert Swenson, and many other geoscientists. We are especially grateful to our reviewers: David LePain and Rick Stanley. The map benefited greatly from the cartographic expertise provided by Joseph Rolfzen and Patricia Gallagher. Gregersen, L.S. Shellenbaum, D.P. 2015 Poster and Presentation Gregersen, L.S. and Shellenbaum, D.P., 2015 Fairbanks, Alaska, United States Alaska Division of Geological & Geophysical Surveys 1 sheet http://dx.doi.org/10.14509/29410 Gregersen, Laura Shellenbaum, D.P. 2010 Poster and Presentation Gregersen, Laura and Shellenbaum, D.P., 2010 Fairbanks, Alaska, United States Alaska Division of Geological & Geophysical Surveys 51 p http://dx.doi.org/10.14509/21801 Shellenbaum, D.P. Gregersen, L.S. Delaney, P.R. 2010 Report of Investigation RI 2010-2 Fairbanks, Alaska, United States Alaska Division of Geological & Geophysical Surveys 1 sheet, scale 1:500,000 http://dx.doi.org/10.14509/21961 Shellenbaum, D.P. Silliphant, L.J. 2008 Poster and Presentation Shellenbaum, D.P. and Silliphant, L.J., 2008 Fairbanks, Alaska, United States Alaska Division of Geological & Geophysical Surveys 24 p http://dx.doi.org/10.14509/21827 The supporting data for the subcrop map vary regionally, and within each region the uncertainty varies. Lower Cook Inlet has the greatest control of all regions: formation picks in the OCS wells, age data, 2-D seismic control, and outcrop. In upper and middle Cook Inlet, well formation picks, age data, and outcrop extents primarily define the subcrop limits, with seismic character and fabric substantiating the interpretation. Along the eastern edge of the subcrop map, where little to no seismic data or well data exist, interpreted aeromagnetic data, outcrop extents, and unpublished zircon age dates (R. Gillis, written commun.) are the main controls on the subcrop map unit boundaries. Map unit boundaries are dashed and are designated with question marks where little to no control is present. The structural surface onto which the subcrop map is projected is taken directly from the top Mesozoic unconformity depth map published by Shellenbaum and others (2010). Contours outside of the CI88 and CI89 two-dimensional seismic coverage are dashed to indicate uncertainty. Contours outside seismic coverage with little well control have even higher uncertainties, and are designated with question marks. There is also a certain amount of spatial uncertainty regarding the intersection of the top Mesozoic unconformity horizon with the Bruin Bay and Castle Mountain-Lake Clark fault systems that bound the basin to the west. The fault traces (Magoon and others, 1976) indicate surface expression, whereas the top Mesozoic surface lies at varying depths. The Border Ranges and Eagle River faults are modified from Wilson and others (2012). The modifications conform to aeromagnetic boundaries shown by data provided by R. Saltus (written commun.) and Haeussler and Saltus, in press. The uncertainty when picking formation tops is qualified by assigning a confidence rating (A = high confidence, B = moderate confidence, and C = low confidence). Lithologic data were unavailable for seven wells. In those cases, wireline log correlations and proximity to known formation picks were used to assign the age. Without core or age date data available at the top Mesozoic unconformity, it is difficult to clearly identify the Upper Jurassic Naknek Formation and the Middle Jurassic Chinitna Formation-Tuxedni Group, undivided, from only cuttings and wireline log signature. Seismic character, proximity to well control with known picks, and proximity to mapped bedrock helped differentiate between the Upper and Middle Jurassic rock units. A complete reference list of supporting data sources that were used to define and delineate geologic units can be found on the associated mapsheet. not applicable This data release is complete. The supporting data for the subcrop map vary regionally, and within each region the uncertainty varies. Map unit boundaries are dashed and are designated with question marks where little to no control is present. Data Collection - Publicly available geological and geophysical data that inform the subcrop map were collected and cataloged. These data include: wireline logs and lithology logs obtained from the Alaska Oil and Gas Conservation Commission (AOGCC); AMSTRAT logs obtained from Canadian Stratigraphic Services; drill cuttings and core available at the Alaska Geologic Materials Center (GMC); palynology data; other biostratigraphic data; Spectrum Geo and Seitel, Inc.-owned seismic data (Spec 2-D Marine CI88 and CI89 prefix); public 1975 Marine seismic data (ALC prefix, donated to the U.S. Geological Survey [USGS] by WesternGeco); aeromagnetic data; geologic maps of the Cook Inlet region; previous subcrop map interpretations; published cross sections through the basin; and the top Mesozoic unconformity depth map for Cook Inlet basin. A complete reference list of originating data sources can be found on the associated map sheet. 2012 Subcrop Map Structural Surface - The Mesozoic subcrop map is projected onto the top Mesozoic unconformity depth surface of Cook Inlet basin, Alaska, published by Shellenbaum and others (2010). This surface is the boundary between the Tertiary sedimentary rocks that comprise the majority of the known oil and gas reservoirs and the underlying Mesozoic strata that include the main source rocks of oil as well as potential petroleum reservoir rocks. The boundaries of the subcrop map are the same as for the map of Shellenbaum and others (2010). 2013 Formation Picks - Formation picks at the top Mesozoic unconformity were determined for 109 wells in Cook Inlet basin (see formation tops table). The formation picks were primarily interpreted from drill cuttings and wireline logs, and, when available, core, palynology, biostratigraphy, and mapped bedrock. Each formation pick was assigned a confidence rating. The easiest subcrop units to distinguish from cuttings and core chips at the top Mesozoic unconformity were the Upper Cretaceous to upper Lower Cretaceous Kaguyak-Matanuska Formations, undivided, the plutonic rocks, undivided, and the metamorphic rocks near the Border Ranges fault, undivided. The most challenging formations to clearly identify in cuttings at the top Mesozoic unconformity were the Upper Jurassic Naknek Formation, the Middle Jurassic Chinitna Formation-Tuxedni Group, undivided, and the Lower Jurassic Talkeetna Formation. The challenge stems from the fact that the Middle Jurassic Chinitna Formation-Tuxedni Group, undivided, contains both volcanic detritus (derived from the volcanic rocks of the Talkeetna Formation) and plutonic detritus (the primary component of the Naknek Formation). Age calls from palynology and biostratigraphy, seismic character, and proximity to mapped bedrock helped differentiate between the Jurassic rock units. A complete reference list of supporting data sources that were used to define and delineate geologic units can be found on the associated map sheet. 2012 Geophysical Interpretation - Two regional 2-D marine seismic data sets were used to interpret three Mesozoic horizons, Upper Jurassic Naknek, Middle Jurassic Tuxedni, and Lower Jurassic Talkeetna (data location map). The primary regional data were the same CI88 and CI89 multi-client data (approximately 2,280 miles, now marketed by Spectrum Geo and Seitel, Inc.) used in the construction of the top Mesozoic unconformity depth map. USGS seismic data from lower Cook Inlet were migrated and interpreted to provide additional control (approximately 1,020 miles, 1975 vintage ALC data available from the USGS National Archive of Marine Seismic Surveys [NAMSS] website). The final interpretation was an internally consistent set of horizon picks that honored all of the well control. Between the wells, the interpretation was sometimes based on wavelet character, but in many areas depended on projections and dip interpretation rather than consistent character picks. The fact that the Talkeetna and Naknek Formations are truncated and bounded by unconformities, respectively, often angular, aids in regional correlation and extrapolation away from well control. Naknek and Tuxedni/Talkeetna horizons are also often characterized by packages of high-amplitude reflections that provide broad indications of continuity where individual reflections do not. Wells with Mesozoic formation tops were used to constrain the horizon picks (Outer Continental Shelf [OCS] wells in lower Cook Inlet and the North Forelands State #1 well in upper Cook Inlet). In the middle and upper Cook Inlet, where Mesozoic well control was sparse, horizon picks were influenced by the formation picks at the top Mesozoic unconformity and by seismic character. Synthetic seismograms from sonic and density logs were created when available, but due to low seismic frequencies and poor signal-to-noise in the deeper data, statistical or character ties were problematic. Insights from the synthetics were used to guide the picks away from wells (for instance, in the OCS synthetics the top Naknek Formation boundary is often characterized by a strong peak); and the Talkeetna Formation often has a strong peak near the base of a high-energy (multiple high-amplitude reflections) section. Picks away from well control were also guided by higher/lower energy trends in the section and interpretations of regional dip. Interpretations were complicated by interference from strong multiples, which overrode true formation dips in many places. Formation top depths were projected in seismic two-way time based on interpolated check shots constrained by the top Mesozoic unconformity depth surface. Public check shots are available in three wells: OCS 0243 (Falcon) 1 (no. 101 on map), OCS 0086 (Guppy) 1 (no. 96 on map), and OCS 0168 (Coho) 2 (no. 93, south of mapped area). In areas where little to no publicly available seismic or well data were available, interpreted aeromagnetic data were used to guide map unit boundaries. A complete reference list of geophysical data sources that were used to interpret rock unit horizons can be found on the associated map sheet. 2013 vector 0.00001 0.00001 decimal degrees North American Datum of 1983 GRS 80 6378137 298.257222101 ri2016-4-border.shp A polygon that encompasses the maximum geographic extent of the data observations Alaska Division of Oil & Gas border ri2016-4-SubCropDepthContours.shp Lines that record depth to the top Mesozoic (base Tertiary) unconformity surface in the Cook Inlet Basin. Depth is measured to top of Mesozoic unconformity in feet below sea level. Contour interval is 1000 ft. The structural surface onto which the subcrop map is projected is taken directly from the top Mesozoic unconformity depth map published by Shellenbaum and others (2010). Shellenbaum, D.P., Gregersen, L.S., and Delaney, P.R., 2010, Top Mesozoic unconformity depth map of the Cook Inlet basin, Alaska: Alaska Division of Geological & Geophysical Surveys Report of Investigation 2010-2, 1 sheet, scale 1:500,000. doi:10.14509/21961. - The overall organization of this file was modified from the NCGMP09 - Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1 by the USGS National Cooperative Geologic Mapping Program (NCGMP), note that all field and table names were derived from the standard but truncated at ten characters or otherwise lightly modified to reflect the content. SubCropDepthContours Type Indicates the type of contour line. Shellenbaum, D.P. and others, 2010 The contour lines are classified as: depth contour, index depth contour, depth contour depression, index depth contour depression, depth contour rise, and index depth contour rise. Value Vertical depth in feet below sea level. Shellenbaum, D.P. and others, 2010 -25000 0 feet LocationCo Indicates positional uncertainty; Contours outside of the CI88 and CI89 two-dimensional seismic coverage are dashed to indicate uncertainty. Contours outside seismic coverage with little well control have even higher uncertainties, and are designated with question marks. There is also a certain amount of spatial uncertainty regarding the intersection of the top Mesozoic unconformity horizon with the Bruin Bay and Castle Mountain-Lake Clark fault systems that bound the basin to the west and north. Shellenbaum, D.P. and others, 2010 The location confidence values are: approximate, out of seismic control, certain, in seismic control, and inferred or doubtful. Label Cartographic labels for index lines. Shellenbaum, D.P. and others, 2010 Contour lines were labeled at the following intervals: 0, -10000, -15000, -20000, -5000, and -25000. ri2016-4-SubCropFaults.shp Lines that record faults that bound map units and dangling faults, modified NCGMP09 format. Alaska Division of Oil & Gas - The overall organization of this file was modified from the NCGMP09 - Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1 by the USGS National Cooperative Geologic Mapping Program (NCGMP), note that all field and table names were derived from the standard but truncated at ten characters or otherwise lightly modified to reflect the content. SubCropFaults Type Specifies the kind of fault represented by the line. Alaska Division of Oil & Gas The faults were classified as: thrust fault, strike-slip fault, generic fault, and normal fault. LocationCo Indicates the degree of certainty in the of the interpretation of the feature. The level of certainty is specific to the map scale. Alaska Division of Oil & Gas The faults were classified as: approximate, certain, and highly uncertain. Source Indicates the bibliographic or data source of the fault. Alaska Division of Oil & Gas, Magoon, L.B., Adkison, W.L., and Egbert, R.M., 1976, Map showing geology, wildcat wells, Tertiary plant fossil localities, K-Ar age dates, and petroleum operations, Cook Inlet area, Alaska: U.S. Geological Survey Miscellaneous Investigations Series, Map I-1019, scale 1:250,000; and Wilson, F.H., Hults, C.P., Schmoll, H.R., Haeussler, P.J., Schmidt. J.M., Yehle, L.A., and Labay, K.A., 2012, Geologic map of the Cook Inlet region, Alaska, including parts of the Talkeetna, Talkeetna Mountains, Tyonek, Anchorage, Lake Clark, Kenai, Seward, Iliamna, Seldovia, Mount Katmai, and Afognak 1:250,000-scale quadrangles: U.S. Geological Survey Scientific Investigations Map 3153, 75 p., 2 plates, scale 1:250,000. The faults were derived or interpreted from: Magoon and others (1976), seismic, and Wilson and others (2012). Label Formal name of selected features. Alaska Division of Oil & Gas The labeled features are: Bruin Bay Fault, Castle Mountain Fault, Border Ranges Fault, Lake Clark Fault, and Eagle River Fault ri2016-4-SubCropMapUnitContacts.shp Lines that record map unit contacts and degree of certainty, modified NCGMP09 format. Alaska Division of Oil & Gas - The overall organization of this file was modified from the NCGMP09 - Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1 by the USGS National Cooperative Geologic Mapping Program (NCGMP), note that all field and table names were derived from the standard but truncated at ten characters or otherwise lightly modified to reflect the content. SubCropMapUnitContacts LocationCo Indicates the degree of certainty in the of the interpretation of the feature. The level of certainty is specific to the map scale. Alaska Division of Oil & Gas The contacts were classified as: certain and approximate. ri2016-4-SubCropMapUnitPolys.shp Polygons that record the distribution of interpreted geologic units, modified NCGMP09 format. Alaska Division of Oil & Gas - The overall organization of this file was modified from the NCGMP09 - Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1 by the USGS National Cooperative Geologic Mapping Program (NCGMP), note that all field and table names were derived from the standard but truncated at ten characters or otherwise lightly modified to reflect the content. SubCropMapUnitPolys MapUnit Short ASCII string that indicates the map unit.. Alaska Division of Oil & Gas JTrtp-Jbrum TALKEETNA FORMATION-BORDER RANGES ULTRAMAFIC AND MAFIC COMPLEX, UNDIVIDED -- Outcrops of the Talkeetna Formation on the east side of the basin are found to the northeast in the Matanuska Valley. These outcrops are highly faulted and are in fault contact with ultramafic and mafic plutonic rocks referred to as the Border Ranges ultramafic and mafic complex (BRUMC). Interpretations of aeromagnetic data suggest that both the BRUMC and the Talkeetna Formation are present on the east side of Cook Inlet basin along the Border Ranges fault (Mankhemthong and others, 2013; Burns and Winkler, 1994; Saltus, written commun.; Burns, 1985; Burns and others, 1991). Outcrops of volcaniclastic rocks, limestone, coal, and tuffaceous argillite (interpreted to be correlative with the Talkeetna Formation) are also present on the east side of the basin at Pogibshi Point near Seldovia (Magoon and others, 1976; Bradley and others, 1999; LePain and others, 2013). Kelley (1980) named these outcrops the Pogibshi Formation. Limestone, contorted chert, and greenstone interpreted as the Port Graham Formation of Kelley (1980) are also found in outcrop in this area. Because no other well data or seismic data are available on the east side of the basin to clearly determine which of the Talkeetna Formation, BRUMC, Pogibshi Formation, or Port Graham Formation subcrops the top Mesozoic unconformity, we include the BRUMC, Pogibshi Formation, and Port Graham Formation with the Talkeetna Formation on the east side of the basin and designate this as a separate map unit, Talkeetna-BRUMC undivided. Alaska Division of Oil & Gas Jc-Jt CHINITNA FORMATION-TUXEDNI GROUP, UNDIVIDED -- In outcrop, the Chinitna Formation and Tuxedni Group are described as light to dark gray and green, marine, fossiliferous, siltstone, sandstone, and shale with the Chinitna Formation having many limy concretions (Detterman and Hartsock, 1966; Detterman and Reed, 1980). Both the Chinitna Formation and the Tuxedni Group contain a mixture of plutonic and volcanic detritus and clasts presumed to be derived from erosion of the Talkeetna Formation and related plutonic rocks of the Early Jurassic magmatic arc (Detterman and Hartsock, 1966; Trop and others, 2005). Two wells, Iniskin Unit Beal (no. 110 on map) and Iniskin Unit Zappa (no. 111 on map), are drilled in surface outcrops of Tuxedni Group. Green-gray and brown-gray siltstone, sandstone, conglomerate, and shale are documented in cuttings in these wells. A Middle Jurassic age was assigned to the rocks at the top Mesozoic unconformity in the State 364651 1 well (no. 105 on map) (Zippi, 2006). The cuttings in those wells are described as light gray to green–gray and brown, claystone, silty claystone, indurated, argillaceous, weathered, and slightly micaceous at the top Mesozoic unconformity. The remaining wells were inferred to penetrate subcrop of Chinitna Formation–Tuxedni Group because of similar cuttings, wireline log signature, and/or proximity to the age-dated wells. Alaska Division of Oil & Gas Jn NAKNEK FORMATION -- The Naknek Formation is described in outcrop as light to dark gray, fossiliferous, marine arkosic sandstone, conglomerate, siltstone, and shale having a primarily plutonic provenance (Detterman and Hartsock, 1966; Detterman and others, 1996; Trop and others, 2005; Wartes and others, 2013b). Multiple wells in the west-central portion of the basin include strata that are assigned an age of Late Jurassic at the top Mesozoic unconformity: Bell Island 1, State SRS 1, MGS State SRS 1, Kalgin Island State 1, and Oldmans Bay State 1 (nos. 102, 59, 65, 54, and 53 on map) (Zippi, 2006; Boss and others, 1976). Cuttings in these wells at the top Mesozoic unconformity are described mostly as gray to gray–green claystone, siltstone with some sandstone, arkose, tuff, and argillite. In the Swanson River field area, the cuttings interpreted to be Naknek Formation include gray to gray–green siltstone, sandstone, claystone, mica, tuff, and glauconite. Alaska Division of Oil & Gas Jtk TALKEETNA FORMATION -- In outcrop, the Talkeetna Formation is described as dark green to black, red, and multicolored lava, agglomerate, breccia, and tuff with interbedded sandstone and shale (Detterman and Hartsock, 1966). The Talkeetna Formation is interpreted to be a product of extrusion and erosion of an Early Jurassic arc (Detterman and Reed, 1980; Trop and Plawman, 2006). The cuttings and core chips interpreted as Talkeetna Formation are described as gray–green–brown–black volcanics, basalt, and tuffs. Alaska Division of Oil & Gas Kkg-Km KAGUYAK-MATANUSKA FORMATIONS, UNDIVIDED -- The Matanuska Formation is described in outcrop as dark-gray, marine shale, siltstone, sandstone, and conglomerate with Inoceramus fragments and ammonites (Grantz, 1964; Trop, 2008). The Kaguyak Formation is described in outcrop as dark gray to pale brown, marine, fossiliferous, siltstone, sandstone, and shale (Detterman and Miller, 1985; Wartes and others, 2013a). Nonmarine sedimentary rocks correlative with the Kaguyak Formation have been documented in the COST well (no. 94 on map) and in outcrop (Magoon, 1986; Magoon, and others, 1980; LePain and others, 2012). The cuttings interpreted as Kaguyak–Matanuska Formations, undivided, are described as dark gray shale, gray–green to gray–brown siltstone, and sandstones with Inoceramus prisms. Palynology data from these wells suggest a Late Cretaceous age (Zippi, 2006), which supports the Kaguyak–Matanuska Formation, undivided, interpretation. Alaska Division of Oil & Gas MzPzmb METAMORPHIC ROCKS NEAR THE BORDER RANGES FAULT, UNDIVIDED -- Metamorphic rocks, primarily metasedimentary, are observed at the top Mesozoic surface along the southeastern edge of the subcrop map. The Metamorphic rocks near the Border Ranges fault, undivided, map unit are described as metasedimentary, metaplutonic, and metavolcanic rocks, metachert, slate, metasandstone, and marble (Magoon and others, 1976). Cuttings descriptions in these wells include sandstone, chert, argillite, quartzite, muscovite, schist, and loose grains of quartz. Haeussler and Saltus's (2011) interpretation of aeromagnetic data suggests that these metasedimentary rocks may be correlative with the McHugh Complex. Alaska Division of Oil & Gas TMzpu PLUTONIC ROCKS, UNDIVIDED -- Plutonic rocks are observed at the top Mesozoic unconformity in wells at three different locations. Two of the areas, which correspond to the Bachatna Creek Unit 7 (no. 31 on map) and the Cottonwood State 1 (no. 49 on map) wells, are in the north-western corner of the subcrop map near outcrops of Jurassic quartz diorite, diorite, and granodiorite (Magoon and others, 1976). The third area, which corresponds to the Fishhook 1 well (no. 7 on map), is in the northeastern corner of the subcrop map near outcrops of Jurassic quartz diorite, diorite, and granodiorite and outcrops of Tertiary-Cretaceous granodiorite and quartz diorite (Magoon and others, 1976). The cuttings in these wells are described as granite, granodiorite, and/or diorite. Alaska Division of Oil & Gas Label The label values provide the FGDCGeoAge font characters that are required to display the geologic symbols that are appropriate to the map unit assigned in the corresponding MapUnit field.. Alaska Division of Geological & Geophysical Surveys FGDCGeoAge font 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. Symbol References the CMYK color value that was assigned to the map unit. Alaska Division of Oil & Gas 2020 CMYK value - C:20%, M:0%, Y:20%, K:0% CMYK values were assigned by DGGS staff based on the standards outlined in the U.S. Geological Survey, 2005, Selection of colors and patterns for geologic maps of the U.S. Geological Survey: Techniques and Methods 11-B1, 19 p.; 1 plate. 0770 CMYK value - C:0%, M:70%, Y:70%, K:0% CMYK values were assigned by DGGS staff based on the standards outlined in the U.S. Geological Survey, 2005, Selection of colors and patterns for geologic maps of the U.S. Geological Survey: Techniques and Methods 11-B1, 19 p.; 1 plate. AA00 CMYK value - C:8%, M:8%, Y:0%, K:0% CMYK values were assigned by DGGS staff based on the standards outlined in the U.S. Geological Survey, 2005, Selection of colors and patterns for geologic maps of the U.S. Geological Survey: Techniques and Methods 11-B1, 19 p.; 1 plate. 6040 CMYK value - C:60%, M:0%, Y:40%, K:0% CMYK values were assigned by DGGS staff based on the standards outlined in the U.S. Geological Survey, 2005, Selection of colors and patterns for geologic maps of the U.S. Geological Survey: Techniques and Methods 11-B1, 19 p.; 1 plate. X270 CMYK value - C:100%, M:20%, Y:70%, K:0% CMYK values were assigned by DGGS staff based on the standards outlined in the U.S. Geological Survey, 2005, Selection of colors and patterns for geologic maps of the U.S. Geological Survey: Techniques and Methods 11-B1, 19 p.; 1 plate. 2070 CMYK value - C:20%, M:0%, Y:70%, K:0% CMYK values were assigned by DGGS staff based on the standards outlined in the U.S. Geological Survey, 2005, Selection of colors and patterns for geologic maps of the U.S. Geological Survey: Techniques and Methods 11-B1, 19 p.; 1 plate. Pattern References the pattern symbol that was assigned to the map unit. Pattern values were assigned by DGGS staff based on the standards outlined in the U.S. Geological Survey, 2005, Selection of colors and patterns for geologic maps of the U.S. Geological Survey: Techniques and Methods 11-B1, 19 p.; 1 plate. Pattern fill used to delineate a sub-unit. Alaska Division of Geological & Geophysical Surveys mailing and physical

3354 College Road

Fairbanks AK 99709-3707 USA (907)451-5020 (907)451-5050 dggspubs@alaska.gov 8 am to 4:30 pm, Monday through Friday, except State holidays Please view our website (http://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible. RI 2016-4 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. Contact DGGS for current pricing Shapefiles http://dx.doi.org/10.14509/29658 Free download 20160718 Alaska Division of Geological & Geophysical Surveys Metadata Manager mailing and physical

3354 College Road

Fairbanks AK 99709-3707 USA (907)451-5020 FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998 If the user has modified the data in any way they are obligated to describe the types of modifications they have performed in the supporting metadata file. User specifically agrees not to imply that changes they made were approved by the Alaska Department of Natural Resources or Division of Geological & Geophysical Surveys. http://www.dggs.alaska.gov/metadata/dggs.ext dggs metadata extensions