71036e8b-b415-43d7-9747-bb8e056f643b_source eng; USA utf8 dataset Alaska Division of Geological & Geophysical Surveys Metadata Manager (907)451-5020 3354 College Road Fairbanks AK 99709-3707 USA pointOfContact 2016-07-18 ISO 19115 Geographic Information - Metadata ISO 19115:2003/Cor.1:2006(E) Top Mesozoic unconformity subcrop map, Cook Inlet basin, Alaska 2016-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Gregersen, L.S. originator Shellenbaum, D.P. originator http://dx.doi.org/10.14509/29658 REPORT AND DIGITAL DATA Report of Investigation RI 2016-4 1 sheet, scale 1:500,000. 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. 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. completed Alaska Division of Geological & Geophysical Surveys GIS Manager 907-451-5020 3354 College Rd Fairbanks AK 99709-3707 USA dggsgis@alaska.gov 8 am to 4:30 pm, Monday through Friday, except State holidays pointOfContact notPlanned 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 theme 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 place 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 stratum Alaska Division of Geological & Geophysical Surveys 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 temporal 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 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. otherRestrictions 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. otherRestrictions 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). Preliminary top Mesozoic unconformity subcrop map, Cook Inlet basin, Alaska (poster): Alaska Geological Society Technical Conference, May 15, 2014 2015-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Gregersen, L.S. originator Shellenbaum, D.P. originator http://dx.doi.org/10.14509/29410 Poster and Presentation Gregersen, L.S. and Shellenbaum, D.P., 2015 1 sheet crossReference Progress on Developing a Cook Inlet Mesozoic Subcrop Map (presentation): U.S. Geological Survey Cook Inlet Geology Review Meeting, Anchorage Alaska, September 21-22, 2010 2010-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Gregersen, Laura originator Shellenbaum, D.P. originator http://dx.doi.org/10.14509/21801 Poster and Presentation Gregersen, Laura and Shellenbaum, D.P., 2010 51 p crossReference Top Mesozoic unconformity depth map of the Cook Inlet basin, Alaska 2010-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Shellenbaum, D.P. originator Gregersen, L.S. originator Delaney, P.R. originator http://dx.doi.org/10.14509/21961 Report of Investigation RI 2010-2 1 sheet, scale 1:500,000 crossReference Cook Inlet Mesozoic subcrop and base Tertiary depth structure mapping (presentation): DNR Spring Technical Review Meeting, Anchorage, March 26-27, 2008 2008-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Shellenbaum, D.P. originator Silliphant, L.J. originator http://dx.doi.org/10.14509/21827 Poster and Presentation Shellenbaum, D.P. and Silliphant, L.J., 2008 24 p crossReference vector eng; USA geoscientificInformation -153.101740 -148.939167 59.186514 61.842144 2010-01-01 2016-01-01 >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. true Shapefiles unknown Alaska Division of Geological & Geophysical Surveys (907)451-5020 (907)451-5050 3354 College Road Fairbanks AK 99709-3707 USA 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. distributor Contact DGGS for current pricing Free download http://dx.doi.org/10.14509/29658 Shapefiles CSDGM IMPORT ERROR: No digtinfo/formcont information dataset Horizontal Positional Accuracy Report 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. This data release is complete. This data release is complete. not applicable This lineage was generated by the FGDC CSDGM to 19139 transformation 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. 2012-01-01T00:00:00 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). 2013-01-01T00:00:00 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. 2012-01-01T00:00:00 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. 2013-01-01T00:00:00 otherRestrictions Metadata Use Constraints: 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. unknown This metadata was automatically generated from the FGDC Content Standard for Digital Geospatial Metadata standard (version FGDC-STD-001-1998) using the 2019-08-12T11:11:00 version of the FGDC CSDGM to ISO 19139 transform. Alaska Division of Geological & Geophysical Surveys Metadata Manager (907)451-5020 3354 College Road Fairbanks AK 99709-3707 USA pointOfContact