Arctic Slope Of Alaska Research Articles

Circumpolar oil-and-gas-bearing basins of the arctic part of the North American continent

Major geotectonic elements of the reviewed territory of the Arctic part of the North American continent are the Hyperborean Precambrian Platform, the Franklin folding belt, the northern part of the Precambrian Canadian platform, and the Mesozoic folding belt of Canada and Alaska. The rise of the Arctic slope of Alaska, the Beaufort Sea, and the Sverdrup basin are located in the southern margins of the Hyperborean Platform. The structure and peculiarities of development of these structural elements are genetically related to the evolution of this platform, as well as the current state of petroleum potential of the most promising exploration region of Arctic in the 21st century. The forced exploration of the Arctic regions of the United States and Canada has become an important milestone in the current development of the world energetics. Up to 100 oil, gas, and gas condensate fields have been discovered as a result of violent studies, and the potential oil and gas reserves in the Arctic part of the North American continent have been estimated to 30 billiion t and 50 trillion cubic meters, respectively. Many prospects are related to the continental slopes of all three above-mentioned basins; the total potential reserves of slopes are estimated as 10–12 billion t of oil and 20–25 trillion cubic meters of gas.

In the Warming Arctic Seas

In the Warming Arctic Seas

Temperature data acquired from the DOI/GTN-P Deep Borehole Array on the Arctic Slope of Alaska, 1973–2013

Abstract. A homogeneous set of temperature measurements obtained from the DOI/GTN-P Deep Borehole Array between 1973 and 2013 is presented; DOI/GTN-P is the US Department of the Interior contribution to the Global Terrestrial Network for Permafrost (GTN-P). The 23-element array is located on the Arctic Slope of Alaska, a region of cold continuous permafrost. Most of the monitoring wells are situated on the Arctic coastal plain between the Brooks Range and the Arctic Ocean, while others are in the foothills to the south. The data represent the true temperatures in the wellbores and surrounding rocks at the time of the measurements; they have not been corrected to remove the thermal disturbance caused by drilling the wells. With a few exceptions, the drilling disturbance is estimated to have been on the order of 0.1 K or less by 1989. Thus, most of the temperature measurements acquired during the last 25 yr are little affected by the drilling disturbance. The data contribute to ongoing efforts to monitor changes in the thermal state of permafrost in both hemispheres by the Global Terrestrial Network for Permafrost, one of the primary subnetworks of the Global Terrestrial Observing System (GTOS). The data will also be useful for refining our basic understanding of the physical conditions in permafrost in Arctic Alaska, as well as providing important information for validating predictive models used for climate impact assessments. The processed data are available from the Advanced Cooperative Arctic Data and Information Service (ACADIS) repository at doi:10.5065/D6N014HK.

Oil source rocks at the mesozoic and cenozoic continental margins: Communication 1. Oil source rocks at continental margins in the Triassic-Jurassic and Neocomian-Aptian

The presence of rocks capable of generating hydrocarbons (HC) in the section of sedimentaryrock basins is an essential criterion for their qualification as structures with oil and gas pools. Although organic matter (OM) is always present as dissemination in genetically different sediments, it is believed that rocks enriched with OM of the sapropel series (2 to 3% Corg) can generate a significant amount of liquid HC. However, rock sequences with the Corg ranging from 3–5 to 15–20% are considered oil source formations. The rock section of large petroliferous basins usually includes one or two source sequences, which generated liquid and gaseous HCs after submergence to high temperature and pressures zones. In the basin confined to the Arctic slope of Alaska, one of the main producers of liquid HC is represented by the Upper Triassic clays and limestones of the Shublik Formation. In the Barents Sea and North Sea basins, such rocks are represented by the Spekk Formation and the Kimmeridge Clay, respectively; in the West Siberian basin, by the Bazhenovo Formation; in the Persian Gulf, by the Fahlian, Sargelu, and Garau formations; in basins of the Caribbean region, by marls and clayey limestones of the La Luna Formation. In perioceanic basins of the South Atlantic, the major source sequences are represented by the Neocomian and Barremian clays and marls. The source rocks are identified as the Lagoa Feia Formation in the Campos and Santos basins. They are cognized as the Black Marlstone or Bukomazi Formation in the Lower Congo, Kwanzaa-Cameroon, and Angola basins.

Spatial heterogeneity of tundra vegetation response to recent temperature changes

AbstractThe spatial heterogeneity of recent decadal dynamics in vegetation greenness and biomass in response to changes in summer warmth index (SWI) was investigated along spatial gradients on the Arctic Slope of Alaska. Image spatial analysis was used to examine the spatial pattern of greenness dynamics from 1991 to 2000 as indicated by variations of the maximum normalized difference vegetation index (Peak NDVI) and time‐integrated NDVI (TI‐NDVI) along latitudinal gradients. Spatial gradients for both the means and temporal variances of the NDVI indices for 0.1° latitude intervals crossing three bioclimate subzones were analyzed along two north–south Arctic transects. NDVI indices were generally highly variable over the decade, with great heterogeneity across the transects. The greatest variance in TI‐NDVI was found in low shrub vegetation to the south (68.7–68.8°N) and corresponded to high fractional cover of shrub tundra and moist acidic tundra (MAT), while the greatest variance in Peak‐NDVI predominately occurred in areas dominated by wet tundra (WT) and moist nonacidic tundra (MNT). Relatively high NDVI temporal variances were also related to specific transitional areas between dominant vegetation types. The regional temporal variances of NDVI from 1991 to 2000 were largely driven by meso‐scale climate dynamics. The spatial heterogeneity of the NDVI variance was mostly explained by the fractional land cover composition, different responses of each vegetation type to climate change, and patterned ground features. Aboveground plant biomass exhibited similar spatial heterogeneity as TI‐NDVI; however, spatial patterns are slightly different from NDVI because of their nonlinear relationship.

Bioclimatic Implications and Distribution Patterns of the Modern Ground Beetle Fauna (Insecta: Coleoptera: Carabidae) of the Arctic Slope of Alaska, U.S.A.

Some 56 species of Carabidae have been previously reported on the Arctic Slope of Alaska; of these, only nine have been found at coastal sites in the region. Though for some taxa (e.g., most species of Bembidion ) this may reflect a lack of suitable habitat in the coastal environment, for most others it probably reflects the summer temperature differences between the relatively cool coastal areas (mean July temp [mJt] of ca. 4°C) and warmer interior sites (mJt of ca. 9-10°C). The boundary between the relatively species-rich interior fauna and the more depauperate coastal fauna is probably also approximated by the inland limit of incursions of cool summer coastal fogs, which coincides with a sharp vegetational boundary. Additional systematic collecting of specimens and a coordinated effort to gather climate data will be needed to delimit distributional limits more closely and to provide background data for both modern environmental monitoring and paleoenvironmental reconstructions.

Structure and wind transport of seasonal snow on the Arctic slope of Alaska

The winter snow on the Arctic slope of Alaska lasts for nine months each year, yet little is known about it from a scientific point of view. Its quantity has been seriously underestimated (by a factor of three) in the weather service records, and the directions and magnitudes of wind-transported snow were unknown before the studies reported here. Our measurements of snow on the tundra indicate two major types which differ in depth, density, overall structure, and thermal characteristics: the veneer facies, lying on and interacting with the tundra, and the drift facies which forms in certain topographic settings. The flux of windblown snow has been determined by repeated measurements on three carefully selected “drift traps”, such as river banks, which are large enough so they do not fill during the winter. The measurements span 30 years to show year-to-year variability. The largest transport of snow is from the prevailing easterly winds; about half as much is transported by storm winds from the west. The lowest amount is transported by katabatic drainage winds which flow from the south out of the Brooks Range; they extend a variable, and largely unknown, distance northward onto the Arctic slope before they yield to the stronger easterly and westerly winds.

Structure and wind transport of seasonal snow on the Arctic slope of Alaska

The winter snow on the Arctic slope of Alaska lasts for nine months each year, yet little is known about it from a scientific point of view. Its quantity has been seriously underestimated (by a factor of three) in the weather service records, and the directions and magnitudes of wind-transported snow were unknown before the studies reported here. Our measurements of snow on the tundra indicate two major types which differ in depth, density, overall structure, and thermal characteristics: the veneer facies, lying on and interacting with the tundra, and the drift facies which forms in certain topographic settings. The flux of windblown snow has been determined by repeated measurements on three carefully selected “drift traps”, such as river banks, which are large enough so they do not fill during the winter. The measurements span 30 years to show year-to-year variability. The largest transport of snow is from the prevailing easterly winds; about half as much is transported by storm winds from the west. The lowest amount is transported by katabatic drainage winds which flow from the south out of the Brooks Range; they extend a variable, and largely unknown, distance northward onto the Arctic slope before they yield to the stronger easterly and westerly winds.

Redistribution of Calving Caribou in Response to Oil Field Development on the Arctic Slope of Alaska

Aerial surveys were conducted annually in June 1978-87 near Prudhoe Bay, Alaska, to determine changes in the distribution of calving caribou (Rangifer tarandus granti) that accompanied petroleum-related development. With construction of an oil field access road through a calving concentration area, mean caribou density (no./sq. km) decreased from 1.41 to 0.31 (P=0.05) with 1 km and increased from 1.41 to 4.53 (P=0.04) 5-6 km from the road. Concurrently, relative caribou use of the adjacent area declined (P<0.02), apparently in response to increasing surface development. We suggest that perturbed distribution associated with roads reduced the capacity of the nearby area to sustain parturient females and that insufficient spacing of roads may have depressed overall calving activity. Use of traditional calving grounds and of certain areas therein appears to favor calf survival, principally through lower predation risk and improved foraging conditions. Given the possible loss of those habitats through displacement and the crucial importance of the reproductive process, a cautious approach to petroleum development on the Arctic Slope is warranted.Key words: Alaska, calving, caribou, disturbance, oil field

Petroleum potential in arctic North America and Greenland

Abstract Sedimentary deposition in Arctic North America and Greenland, in Phanerozoic time, occurred north of the Precambrian Canadian Shield and extended from the Wandel Sea in the east to the Chukchi Sea in the west. Seven geological provinces considered to be highly prospective for oil and gas exist within the region. Lower Paleozoic sediments may exceed 3000 m (10 000 ft) in the several separate basins in the Arctic Interior Platform of the Central Stable Region. To the north of the Arctic Interior Platform, lower Paleozoic sediments thicken into the Franklinian Geosyncline, the second geological province. Twelve thousand metres of lower and middle Paleozoic rocks are folded and faulted along a sinuous belt extending from the Wandel Sea in northeastern Greenland to Prince Patrick Island in the western Canadian Arctic Islands. Unconformably overlying the Franklinian Geosyncline are two successor basins, the third and fourth geological provinces considered in this report. The Sverdrup Basin in the Canadian Arctic Islands contains over 13 000 m (43 000 ft) of upper Paleozoic, Mesozoic and Tertiary sediments. The Wandel Sea Basin in and adjacent to northeastern Greenland, analogous to the Sverdrup Basin, contains a similar complement of upper Paleozoic, Mesozoic and Tertiary sediments. Onshore in Greenland, a composite thickness of 3000 m (10 000 ft) of sediments has been described and offshore, beneath the continental shelf, sediments in the basin may thicken to 10 000 m (33 000 ft). The Arctic Slope of Alaska, the fifth province, exhibits characteristics of a successor basin that has been rotated, translated or otherwise displaced from the Arctic Ocean Basin. Beneath a thickness of some 10 000 m (33 000 ft) of upper Paleozoic, Mesozoic and Tertiary strata is a folded and faulted lower and middle Paleozoic terrane similar to the Franklinian Geosyncline «Fold Belta. The southern margin of this province, now containing the Brooks Range, was folded and faulted during the Laramide Orogeny. A sixth province, the Arctic Coastal Plain, extends along the continent's northern margin from Alaska, to northern Greenland. Strata ranging in age from Jurassic through Pleistocene thicken abruptly from a featheredge to more than 12 000 m (39 000 ft) as they prograde into the Arctic Ocean Basin. The seventh major geologic province is the Baffin Bay Basin, which contains some 10 000 m (33 000 ft) of Mesozoic and Tertiary sediments. With the exception of the Wandel Sea Basin, each of the geological provinces has had its petroleum potential evaluated from well-data. The Arctic Slope of Alaska has hydrocarbon reserves in the order of 1.6 × 109 m3 (10.0 Bbbl) of oil and 750 × 109 m3 (26.5 Tcf) of natural gas. Recoverable reserves for the Beaufort Sea-Mackenzie Delta region of the Arctic Coastal Plain are tentatively considered to be 0.15 × 109 m3 (943 MMbbl). The potential natural gas reserves for the Beaufort Sea-Mackenzie Delta region are in the range of 0.25 × 1012 m3 (8.83 Tcf). The Sverdrup Basin has yet to have significant reserves of oil indicated but the potential reserves of natural gas range from a minimum of 0.45 × 1012 m3 (15.89 Tcf) up to what will probably prove to be more than 565 × 109m3 (20 Tcf) with effective delineation drilling. The Franklinian Geosyncline contains both oil and gas but no significant reserves have been developed. The Wandel Sea Basin, Baffin Bay Basin and Arctic Stable Platform have yet to produce indications of significant pooled hydrocarbons. The undiscovered resource potentials of the Arctic Slope and contiguous Arctic Coastal Plain of Alaska have been estimated to have median values of 3.0 × 109 m3 (18.9 Bbbl) of oil and 1.39 × 1012m3 (49.08 Tcf) of natural gas. The undiscovered resource potentials of the Beaufort Sea-Mackenzie Delta region of the Arctic Coastal Plain have expected values of 1.35 × 109m3 (8.45 Bbbl) of oil and 2.91 × 1012m3 (102.75 Tcf) of natural gas. The combined resource potential of the Arctic Interior Platform, Franklinian Geosyncline, Sverdrup Basin and Baffin Bay Basin have expected values of 0.82 × 109 m3 (5.16 Bbbl) of oil and 2.98 × 1012 m3 (105 Tcf) of natural gas. The resource potential of the Arctic Islands Coastal Plain has not yet been effectively evaluated because the greater portion of the region lies beneath constantly shifting pack-ice and data required for a meaningful assessment are not available. It is possible however, that the Coastal Plain in the Arctic Islands area may have resource potentials as great as any other previously assessed Arctic province. Formal estimates of the resource potentials of northern Greenland and the Wandel Sea Basin are not available but on the basis of comparable geology, values can be expected to be proportional to those of the Arctic Interior Platform, the Franklinian Geosyncline and the Sverdrup Basin, respectively.

Movements of collared Caribou, Rangifer tarandus, in relation to petroleum development on the Arctic Slope of Alaska

Movements of collared Caribou, Rangifer tarandus, in relation to petroleum development on the Arctic Slope of Alaska

A Review of the Utility of Remote Sensing in Alaskan Permafrost Studies

This paper reviews the uses of remote sensing techniques for studies of permafrost related features and processes in Alaska. Remote sensing is ideally suited for studying the Arctic because of the inherent problems associated with obtaining in situ measurements in the harsh Arctic environment. Aircraft thermal infrared imagery, aircraft SAR (Synthetic-Aperture Radar), and helicopter-borne shortpulse radar data are also discussed. It is shown that thermal infrared, aircraft SAR, and Landsat data are all useful for qualitative determination of lake depth of the thaw lakes in northern Alaska. Lakes frozen to their beds can be distinquished from lakes not frozen to their beds using thermal infrared and aircraft SAR imagery. Summer Landsat imagery has been used to monitor lake ice cover dissipation, a relative measure of ice thickness and lake depth. Landsat data have also been used to study the distribution and interannual variability of stream aufeis on the Arctic Slope of Alaska. In addition, break-up characteristics and floods have been studied using Landsat data. Shortpulse radar data are being used experimentally to study subsurface permafrost features, and to examine subsurface homogeneity for construction purposes. In addition, Landsat digital data have been used to measure the one year recovery of tundra following a wildfire in northwestern Alaska. Use of remotely sensed data has substantially increased our understanding of processes operating in Arctic land areas as evidenced by the variety of studies that have been undertaken using data from different parts of the electromagnetic spectrum.

COMPUTER‐ASSISTED INTERPRETATION OF ELECTROMAGNETIC SOUNDINGS OVER A PERMAFROST SECTION

In two‐loop electromagnetic sounding, the electromagnetic coupling between two vertical‐axis loops of wire is measured as a function of frequency, for frequencies ranging from 20 Hz to 20 kHz. If the electrical structure of the earth beneath the loops is horizontally stratified, these data may then be interpreted in terms of a sequence of layer resistivities and thicknesses. This interpretation is accomplished by computing a series of curves for various resistivity profiles and comparing them with the field data to determine which matches best. Calculation of the theoretical models is carried out by applying a linear filter to solve the appropriate integral expression. Interpretation is aided by using an interactive nonlinear least‐squares algorithm iteratively to adjust the model parameters. This procedure was used to interpret two‐loop induction soundings made along the Arctic Slope of Alaska during 1969 to determine permafrost thickness and character. The results indicate that two‐loop induction sounding is an effective method for mapping permafrost characteristics.

Winter Food Habits of Ravens on the Arctic Slope of Alaska

Analysis of 684 pellets from a winter roost of ravens (Corvus corax) at Umiat, Alaska, indicated that during the winters of 1966 and 1967 ravens obtained half of their energy income through predation and half through scavenging. Microtine rodents provided the bulk of the predatory half of the raven's diet, whereas carcasses of caribou (Rangifer arcticus) and ptarmigan (Lagopus spp.) were the items most often scavenged. The relative abundance of prey species in pellets suggests that ravens spent most of their time hunting in upland habitats on the tundra.

Itkilyariak Formation: New Mississippian Formation of Endicott Group, Arctic Slope of Alaska

The Itkilyariak Formation of Mississippian age has been recognized for at least 300 mi (480 km) along a linear trend both on the surface and in the subsurface of the northern Arctic Slope, Alaska. Typical lithologies in the formation are red and maroon sandstone, conglomerate, breccia, and limestone interbedded with maroon and greenish-gray shale and light-gray quartzitic sandstone. The Itkilyariak is gradational with the overlying Alapah Limestone of the Lisburne Group. The base of the formation is probably an unconformity. Outcrop thickness is as much as 150 ft (45 m), but over 500 ft (150 m) of redbeds in a similar stratigraphic position have been found in some wells. Irregular distribution suggests that the formation is related to the truncation of pre-Mississippian c astic rocks. The formation is thought to grade in a short distance southward to the normal marine shales and carbonates of the Endicott and Lisburne Groups, and is believed to have been deposited near the Mississippian shoreline. A Late Mississippian fauna has been collected from a surface exposure.

Biostratigraphy of Niobrara-Equivalent Part of Mancos Shale (Cretaceous) in Northwestern Colorado

Study of microfossils, particularly Foraminifera, from the part of the Cretaceous Mancos Shale in northwestern Colorado that is equivalent to the Niobrara Formation of the High Plains region has determined that these fossils can be used to establish biostratigraphic subdivisions and interpret paleogeographic conditions. The microfossils used in the investigation came from two surface sections and one well in northwestern Colorado and one surface section in northeastern Colorado. The microfauna contains several species in common with beds of the same age in the Gulf Coast and Great Plains areas, and also contains forms which have been reported from equivalent beds in Alberta and the Arctic Slope of Alaska. The microfossils are predominantly calcareous and represent a limited number of planktonic and benthonic forms. Samples taken throughout each of the sections were studied and plotted systematically to determine the stratigraphic distribution of the microfossils. Concentrations of larger numbers of fossils were found in the lower part of the Niobrara-equivalent strata. This lower part is characterized in both northwestern and northeastern Colorado by a variety of benthonic calcareous foraminifers, notably species of Globorotalites and Bifarina, and Pleurostomella austiniana. It is termed informally the Globorotalites interval. Further study may make possible the subdivision of this interval on the basis of the stratigraphic distribution of Globorotalites and Bifarina. The microfauna of the upper part of the section is more limited and is characterized particularly by some species of Gavelinella, notably G. talaria. This upper part is termed the Gavelinella interval. Throughout the Niobrara-equivalent section the planktonic species Heterohelix lobulosa and Hedbergella loetterlei are common, and in most samples the planktonic forms predominate. Interpretation of the environment of deposition of the northwestern Colorado beds has been based on (1) the ratio of planktonic to benthonic foraminifers, (2) modern analogues of foraminiferal genera found as fossils, (3) size and abundance of microfossils, and (4) variety of genera and species. The evidence indicates that large volumes of clay-size clastic sediment were supplied to northwestern Colorado during the deposition of the Niobrara-equivalent part of the Mancos Shale. This fine-grained clastic material diluted the population of foraminifers found as fossils in the sediment (in comparison with the living population) and may have restricted the variety of genera and species. The absence of keeled foraminifers in Niobrara-equivalent beds in northwestern Colorado indicates colder water temperatures (probably less than 20° C) in this region than in areas on the south and east at the same time. The colder water temperatures, as well as the distribution of fine-grained clastic sediment, probably resulted from a combination of a southward-directed, nearshore circulation system along the western boundary of the western interior seaway and the possible upwelling of deeper, colder water. Ratios of planktonic to benthonic Foraminifera and modern analogues of some genera indicate that the seaway was probably on the order of 200 m deep in northwestern Colorado during deposition of the Niobrara-equivalent beds.

Succession on River Alluvium in Northern Alaska

During the summer of 1953, a study was made of the vegetation adjacent to several of the major rivers on the Arctic Slope of Alaska. Much of the descriptive work and all of the quantitative sampling included here were carried out along the Colville River near Umiat, Alaska (N 690 22', W 1520 08'; elevation approximately 350 feet). These data were supplemented through observations by the second author at several other poin-ts on the Arctic Slope. This portion of Alaska, except possibly under the deeper lakes, is underlain by continuous permafrost. The vegetation of the region, except on and immediately adjacent to the river floodplains, is composed of one or more, usually several, of the various tundra plant communities (Spetzman 1951, Cantlon & Bormann 1953, Churchill 1955, Bliss 1956). On the floodplains and lower terraces, plant communities occur in which the plants are both of a lower life-form and of a somewhat higher life-form than the adjoining tundra communities. These are, respectively, the open, perennial-herb pioneer community and the tall (up to 20 feet), fairly dense, feltleaf willow (Salix alaxensis2) communities. Both are of successional status and as the direct influence of the river becomes less through meander migration, they give way by stages to one of the several tundra types that are not dependent upon the river influence. The object of the present study is to describe in a preliminary way the zonation and apparent successional relationships of the vegetation along rivers in the area.

Cliff-Nesting Canada Geese on the Arctic Slope of Alaska

Cliff-Nesting Canada Geese on the Arctic Slope of Alaska

Leucocytozoon bonasae in Ruffed Grouse; Its Possible Relationship to Fluctuations in Numbers of Grouse

During the summer of 1949, Canada geese were observed by pilots, survey crews, and the author on the Colville River, from the headwaters to the 70th parallel on the arctic slope of Alaska. Reports by Eskimos that the geese nest on cliffs of the river was confirmed by locating a single nest and seeing a number of paired birds on the steep north banks. The banks are almost vertical and capped with overhanging tundra. The base continually sloughs into the river during periods of intense flow. The slopes are barren except for scattered bunches of grass and an occasional patch of willow. Climbing the 50to 300-foot slopes is treacherous. A search of about 10 miles of bank resulted in finding only one nest but geese were flushed from many inaccessible points. The nest (July 9, 1949) was in the open, 45 feet above the turbulent water and 50 feet below a rock ledge. The incubating goose was not flushed but the mate was nearby and left the scene. Geese were seen and flushed from similar locations along the Colville. The cliffs of the Colville are undoubtedly a favorite nesting site of the Canada goose in the Arctic. Non-breeding birds were observed on the river bars. Weights and measurements of five nonbreeders, banded on July 12 and 13, identify the species as Branta canadensis leucopareia. A survey party located a nest with 6 eggs on the Etivluk River on July 5, 1949. Accepted for publication January 9, 1953.

Geothermal investigations on the arctic slope of Alaska

Preliminary results of geothermal investigations now in progress near Barrow, Alaska, indicate that, below the level to which seasonal changes penetrate, ground temperatures do not fall below about −10°C. The depth of the 0°C isogeotherm ranges from 670 to 1300 ft, increasing with the distance from the nearest large body of water. Thermal disturbances caused by drilling in and through the permafrost persist for many months, so that thermal readings taken in freshly drilled holes appear to have little value. Some correlation between terrain, electrical resistivity of the ground at shallow depths, and ground temperatures is indicated.