Cryosols in Alaska

Ordinary General Meeting 9 December 1970 at 5.00 p.m. This meeting was devoted to a presentation by staff of The British Petroleum Company Ltd, on Alaskan exploration and the development of the Prudhoe Bay Oilfield. 1. The general geology of northern Alaska By R. Stoneley. Alaska is a country of over half-a-million square miles. It can be divided into three major geological-physiographical provinces: southern Alaska formed of the arcuate Pacific Mountain System (the Aleutian-Alaska and Coastal Ranges, separated by depressions), central or interior Alaska which is the counterpart of the inter-montane plateaux of the western United States, and northern Alaska, the extension of the Rocky Mountain System and Interior Plains. Northern Alaska, on which attention was focussed in the lecture, includes the Brooks Range, the Arctic Foothills and the treeless tundra of the Arctic Coastal Plain or Slope, in all an area of about 125000 square miles. The Brooks Range is a continuous chain of mountains composed of Palaeozoic and early Mesozoic sedimentary rocks which in the western and central part are thrust northwards over the Mesozoic rocks of the foothills. The Arctic foothills are underlain by a very thick succession of Cretaceous flysch and molasse which in the southern part show complex fold and thrust structures comparable with the foothills structures of the Canadian Rockies. In the northern foothills the Cretaceous beds exposed at the surface are folded into a series of long, narrow anticlines and broader synclines which for the most part die out at depth in a

Active faults of Alaska

Drained thaw lake basin recovery on the western Arctic Coastal Plain of Alaska using high-resolution digital elevation models and remote sensing imagery

The North Slope of the Brooks Range in Alaska spans three physiographic provinces: the Coastal Plain, the Brooks Range Foothills, and the Brooks Range proper (Hultén 1968). The vegetation of the foothills province, which includes the Imnavait Creek watershed, is composed of a complex mosaic of communities that is tightly coupled to environmental gradients. This mosaic encompasses exposed upland ridges and mountain slopes, which have communities similar to those found in large areas of the High Arctic (Bliss and Matveya 1992), and, at the other extreme, the communities in valley basins resemble the sedge meadows of the Coastal Plain (Webber 1978). The distribution of these tundra communities is influenced by glacial history and topography, soil development, cryoturbation effects, and local erosion (Walker and Everett 1991; Chap. 4 this Vol.), as well as by summer thaw depth and soil water mobility (Giblin et al. 1992).

BackgroundPleistocene climatic instability had profound and diverse effects on the distribution and abundance of Arctic organisms revealed by variation in phylogeographic patterns documented in extant Arctic populations. To better understand the effects of geography and paleoclimate on Beringian freshwater fishes, we examined genetic variability in the genus Dallia (blackfish: Esociformes: Esocidae). The genus Dallia groups between one and three nominal species of small, cold- and hypoxia-tolerant freshwater fishes restricted entirely in distribution to Beringia from the Yukon River basin near Fairbanks, Alaska westward including the Kuskokwim River basin and low-lying areas of Western Alaska to the Amguema River on the north side of the Chukotka Peninsula and Mechigmen Bay on the south side of the Chukotka Peninsula. The genus has a non-continuous distribution divided by the Bering Strait and the Brooks Range. We examined the distribution of genetic variation across this range to determine the number and location of potential sub-refugia within the greater Beringian refugium as well as the roles of the Bering land bridge, Brooks Range, and large rivers within Beringia in shaping the current distribution of populations of Dallia. Our analyses were based on DNA sequence data from two nuclear gene introns (S7 and RAG1) and two mitochondrial genome fragments from nineteen sampling locations. These data were examined under genetic clustering and coalescent frameworks to identify sub-refugia within the greater Beringia refugium and to infer the demographic history of different populations of Dallia.ResultsWe identified up to five distinct genetic clusters of Dallia. Four of these genetic clusters are present in Alaska: (1) Arctic Coastal Plain genetic cluster found north of the Brooks Range, (2) interior Alaska genetic cluster placed in upstream locations in the Kuskokwim and Yukon river basins, (3) a genetic cluster found on the Seward Peninsula, and (4) a coastal Alaska genetic cluster encompassing downstream Kuskokwim River and Yukon River basin sample locations and samples from Southwest Alaska not in either of these drainages. The Chukotka samples are assigned to their own genetic cluster (5) similar to the coastal Alaska genetic cluster. The clustering and ordination analyses implemented in Discriminant Analysis of Principal Components (DAPC) and STRUCTURE showed mostly concordant groupings and a high degree of differentiation among groups. The groups of sampling locations identified as genetic clusters correspond to geographic areas divided by likely biogeographic barriers including the Brooks Range and the Bering Strait. Estimates of sequence diversity (θ) are highest in the Yukon River and Kuskokwim River drainages near the Bering Sea. We also infer asymmetric migration rates between genetic clusters. The isolation of Dallia on the Arctic Coastal Plain of Alaska is associated with very low estimated migration rates between the coastal Alaska genetic cluster and the Arctic Coastal Plain genetic cluster.ConclusionsOur results support a scenario with multiple aquatic sub-refugia in Beringia during the Pleistocene and the preservation of that structure in extant populations of Dallia. An inferred historical presence of Dallia across the Bering land bridge explains the similarities in the genetic composition of Dallia in West Beringia and western coastal Alaska. In contrast, historic and contemporary isolation across the Brooks Range shaped the distinctiveness of present day Arctic Coastal Plain Dallia. Overall this study uncovered a high degree of genetic structuring among populations of Dallia supporting the idea of multiple Beringian sub-refugia during the Pleistocene and which appears to be maintained to the present due to the strictly freshwater nature and low dispersal ability of this genus.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-015-0413-2) contains supplementary material, which is available to authorized users.

Shallow thaw (thermokarst) lakes abundant in regions of permafrost-affected peatlands represent important sources of carbon dioxide and methane emission to the atmosphere, however the quantitative parameters of phytoplankton communities which control the C cycle in these lakes remain poorly known. This is especially true considering the roles of permafrost, hydrochemical composition of lakes, lake sizes and season as major governing factors on phytoplankton abundance and biodiversity. In this work, we quantified phytoplankton characteristics of 27 thermokarst lakes (sizes ranging from 115 m2 to 1.24 km2) sampled in spring, summer and autumn across a permafrost gradient (isolated, sporadic, discontinuous and continuous zone) in the Western Siberia Lowland (WSL). The biodiversity indices were highest during all seasons in lakes of the continuous permafrost zone and rather similar in lakes of isolated, sporadic and discontinuous permafrost zone. Considering all seasons and permafrost zones, the biomass and cell number of phytoplankton correlated with Dissolved Organic Carbon (DOC), phosphate, and some metal micro-nutrients (Ni, Zn). The strongest correlations were observed for Cyanophycea during summer, with pH, Ni, Cu, Zn, Sr, Ba (cell number) and Cu, Zn, Ba (biomass), and during autumn, with DOC, K, Cr, Cu, Zn, Ba, Cd, Pb (biomass). Using a substituting space for time approach for climate warming and permafrost thaw and suggesting a shift in permafrost boundaries northward, we foresee an increase in cell number and biomass in continuous permafrost zone in spring and summer, and a decrease in phytoplankton abundance in the discontinuous and sporadic permafrost zones. The biodiversity of phytoplankton in the continuous permafrost zone might decrease whereas in other zones, it may not exhibit any sizably change. However, in case of strong deepening of the active layer down to underlaying mineral horizons, and the release of some limiting nutrients (Si, P) due to enhanced connectivity of the lake with groundwater, the share of cyanobacteria and diatoms may increase.

The Overthrust Belt extends for 5000 mi (8000 km) from the Brooks Range in Alaska to the Sierra Madre Oriental in Mexico. It consists of northeastward vergent thrust and fold structures involving late Precambrian to early Tertiary sedimentary section. These sediments represent deposition off the western rift margin, formed in late Precambrian time, of the North American Precambrian craton. The northeastward thrusting continued throughout the Mesozoic as a response to the convergence of the East Pacific Plate with the North American Plate. This convergence resulted in subduction beneath the North American Plate except at the northwest end (the Brooks Range) where the result was obduction. Convergence ceased when the west edge of the East Pacific Plate reached the subduction zone. The sedimentary section involved in the Thrust Belt contains good Devonian to Cretaceous hydrocarbon source rocks, and Ordovician to traps related to the thrusting (simple thrust sheets, imbricate thrust sheets, folded thrust sheets, step anticlines, footwall cutoffs, footwall anticlines, etc.). Field methods involved in exploration for hydrocarbons include field geological mapping, remote sensing (aerial photography and Landsat imagery), various seismic refraction and seismic reflection techniques (including modern detailed three dimension surveys) and potential field methods such as gravity and magneticmore » surveying. Studies of the field data include paleontology, source rock and hydrocarbon migration studies, structural and stratigraphic analyses, and the processing of geophysical data. This work has succeeded in two major areas: the Western Canadian Rocky Mountain Foothills, a major gas province producing mainly from Paleozoic reservoirs; and the Wyoming-Idaho-Utah portion of the thrust belt, also a major gas producer from Paleozoic reservoirs and, in addition, a major oil producer from the Jurassic Nugget Sandstone.« less

Summarizes briefly the geologic setting and geomorphic features of the Brooks Range, Arctic Foothills and coastal plain, and reviews the Naval Arctic Research Lab-sponsored research in fields of geomorphology, oriented lakes, patterned ground, glacial geology, palynology, C-14 dating and shoreline, near-shore and shallow-water studies. Discussion of the status of geologic research and future role of NARL notes the large sums of money presently being spent on subsurface and geophysical research by oil companies, and suggests that NARL concentrate, rather, on studies of processes, the Pleistocene and the Precambrian.

Biogeochemistry of macrophytes, sediments and porewaters in thermokarst lakes of permafrost peatlands, western Siberia

Because landslide regimes are likely to change in response to climate change in upcoming decades, the need for mechanistic understanding of landslide initiation and up-to-date landslide inventory data is greater than ever. We conducted surficial geologic mapping and compiled a comprehensive landslide inventory of the Denali National Park road corridor to identify geologic and geomorphic controls on landslide initiation in the Alaska Range. The supplemental geologic map refines and improves the resolution of mapping in the study area and adds emphasis on surficial units, distinguishing multiple glacial deposits, hillslope deposits, landslides, and alluvial units that were previously grouped. Results indicate that slope angle, lithology, and thawing ice-rich permafrost exert first-order controls on landslide occurrence. The majority (84%) of inventoried landslides are <0.01 km2 in area and occur most frequently on slopes with a bimodal distribution of slope angles with peaks at 18° and 28°. Of the 85 mapped landslides, a disproportionate number occurred in unconsolidated sediments and in felsic volcanic rocks. Weathering of feldspar within volcanic rocks and subsequent interactions with groundwater produced clay minerals that promote landslide initiation by impeding subsurface conductivity and reducing shear strength. Landslides also preferentially initiated within permafrost, where modeled mean decadal ground temperature is −0.2 ± 0.04 °C on average, and active layer thickness is ∼1 m. Landslides that initiated within permafrost occurred on slope angles ∼7° lower than landslides on seasonally thawed hillslopes. The bimodal distribution of slope angles indicates that there are two primary drivers of landslide failure within discontinuous permafrost zones: (1) atmospheric events (snowmelt or rainfall) that saturate the subsurface, as is commonly observed in temperate settings, and (2) shallow-angle landslides (<20° slopes) in permafrost demonstrate that permafrost and ice thaw are also important triggering mechanisms in the study region. Melting permafrost reduces substrate shear strength by lowering cohesion and friction along ice boundaries. Increased permafrost degradation associated with climate change brings heightened focus to low-angle slopes regionally as well as in high-latitude areas worldwide. Areas normally considered of low landslide potential will be more susceptible to shallow-angle landslides in the future. Our landslide inventory and analyses also suggest that landslides throughout the Alaska Range and similar climatic zones are most likely to occur where low-cohesion unconsolidated material is available or where alteration of volcanic rocks produces sufficient clay content to reduce rock and/or sediment strength. Permafrost thaw is likely to exacerbate slope instability in these materials and expand areas impacted by landslides.

We compared productivity and nesting success of 2 adjacent populations of bald eagles (Haliaeetus leztcocephalus) near the northern limits of their range in interior Alaska during 1989-94. Productivity (f 2 SE young fledgedloccupied territory) and nesting success differed between populations; pairs in the Gulkana River basin had higher productivity (0.86 2 0.05, n = 274) and nesting success (59%) than those in the Copper River basin (0.71 2 0.04, 48%, n = 471; P < 0.02). Productivity varied both annually and spatially within each basin (P < 0.001). However. brood sizes of successful nests were identical for both basins (1.48 f 0.03). suggesting that variability in productivity resulted largely from differences in nesting success. Patterns of vari- ability in reproductive success within a territory also were similar for both populations. Pairs that were suc- cessful one year fledged more offspring, were more likely to be successful, were more likely to reoccupy the same territory, and were less likely to change nest locations the following year compared to pairs that were unsuccessful the previous year (P < 0.025 for all comparisons). Most nesting failure (92%) occurred during incubation when weather conmtions tend to be most severe. However, reproductive success was not negatively correlated with severity of spring weather (temp or rainfall) or strongly correlated with prey abundance during brood rearing. We hypothesize that annual and spatial variability in reproductive success of these northern bald eagle populations may be associated with variation in prey availability, especially before and during incubation. J. WILDL. MANAGE. 61(4):1313-1321

Large, late-winter ptarmigan migrations heavily impact the shoot, plant, and patch architecture of shrubs that remain above the snow surface. Ptarmigan browsing on arctic shrubs was assessed in the vicinity of Toolik Lake, on the north side of the Brooks Range in Alaska. Data were collected in early May 2007, at maximum snow depth, after the bulk of the ptarmigan migration had passed through the area. In an area of tall shrubs, half of the buds on Salix alaxensis were browsed by ptarmigan. Three percent of the buds that were buried beneath the snow were browsed, 90% of the buds that were less than 30 cm above the maximum snow level were browsed, and 45% of the buds above that height were browsed. Ptarmigan browsing was found to be a major height limiter for tall shrubs, thereby controlling shrub architecture by brooming stems at the snow surface and inducing stump shoots. These results were qualitatively extrapolated by photographing shrub morphology over a region approximately 300 km wide across a series of north-flowing arctic rivers with headwaters in the Brooks Range. Ptarmigan “hedging” of shrub patches, and shrub growth under a warmer climate, are opposing forces mediated by snow distribution.

The Umiat oil field is in Naval Petroleum Reserve No.4 between the Brooks Range and Arctic Ocean in far-northern Alaska. The Umiat anticline has been tested by 11 wells, six of which produced oil; however, the productive capacity and recoverable reserves of the field are subject to considerable speculation because of unusual reservoir conditions and because several wells appear to have been seriously damaged during drilling and completion. Oil is produced at depths of 275 to 1,100 ft; the depth to the bottom of the permanently frozen zone varies from about 800 to 1,100 ft, so that most of the oil reserves are in the permafrost. Reservoir pressures are estimated to range from 50 to 350 psi, increasing with depth, and the small amount of gas dissolved in the oil is the major source of energy for production. Laboratory tests were made on cores under simulated permafrost conditions to estimate oil recoverable by solution-gas expansion from low saturation pressures. The cores were also tested for clay content and susceptibility to productivity impairment by swelling days and increased water content if exposed to fresh water. The results indicate that oil can be produced from reservoir rocks in the permafrost and that substantial amounts of oil can be produced from depletion-drive reservoirs by a pressure drop of as little as 100 psi below the saturation pressure. Freezing of formation water reduces oil productivity much more than that due to increased oil viscosity. Failure of wells drilled with water-base mud to produce is attributed to freezing of water in the area immediately surrounding the wellbore. Swelling clays apparently contributed very little to the plugging of the wells. Introduction Naval Petroleum Reserve No.4 lies between the Brooks Range and the Arctic Ocean in northern Alaska. The Umiat oil field is located in the southeastern part of the Reserve and is about 180 miles southeast of Point Barrow (the only permanent settlement in the Reserve and the primary supply point for drilling of the wells at Umiat).

Discoveries of natural gas in Alaska have resulted from the search for oil, which has continued intermittently since about 1898. In northern Alaska two gas fields and two prospective gas fields, as well as two oil fields and one prospective oil field, have been discovered in Mesozoic rocks. All other discoveries have been made in Tertiary rocks along the southern coast of Alaska. Except for a small shallow oil field at Katalla, all of these discoveries have been in the Cook Inlet subprovince, which contains a fully developed major oil field, an undeveloped oil field, two major natural gas fields, eight unevaluated or smaller gas fields, and important gas prospects. Alaska is grossly similar in geology, as well as in physiography, to the western part of the conterminous United States and western Canada. During Paleozoic and early Mesozoic time, it was a part of the Cordilleran geosyncline—the eugeosynclinal part over southern Alaska and the miogeosynclinal part over northern Alaska. In mid-Mesozoic time the bedrock surface of Alaska was warped into alternating geanticlines and geosynclines. The sediments that filled the geosynclines were predominantly clastic, and for the most part graywacke assemblages. Alaska has been largely emergent since the end of the Cretaceous Period. During the Tertiary Period, local downwarping formed several elongate basins that were filled with clastic sediments. Most of these were nonmarine, but marine invasions entered a few marginal basins at the southern and northern borders of Alaska. Areas considered for gas and oil possibilities include the Alaska Peninsula-Cook Inlet province, the Bristol Bay Tertiary province, the Pacific-margin Tertiary province, and the Bering Sea shelf in southern Alaska; the Arctic Slope province across northern Alaska; and the Yukon-Koyukuk and Yukon-Porcupine provinces of western and eastern interior Alaska, respectively. The Alaska Peninsula-Cook Inlet province consists of a long, narrow prism (more than 900 mi long and 5 to 60 mi wide) of slightly to moderately deformed late Mesozoic marine clastic rocks, whose composite thickness exceeds 30,000 ft. In the Cook Inlet subprovince, coal-bearing nonmarine, slightly to moderately deformed, Tertiary clastic rocks, whose composite thickness may exceed 25,000 ft, overlie the Mesozoic rocks. The Mesozoic rocks contain several gas and oil seeps and have produced shows of oil and gas in test wells, but no commercial production has been found. The Tertiary rocks contain the major known reserves and the only significant production of oil and gas in Alaska. The area considered to have petroleum possibilities is 5-60 mi wide and about 250 mi long. The Bristol Bay Tertiary province, about 250 mi long and as much as 30 or more miles wide, is underlain by poorly exposed marine and nonmarine Tertiary clastic rocks. No indications of petroleum have been reported, and three test wells were dry. Rocks of the Pacific-margin Tertiary province crop out along the coast from Icy Point in southeastern Alaska to Chirikof Island (southwest of Kodiak Island), and these rocks may extend offshore to fringe the entire Pacific margin and form a belt roughly 40,000 sq mi in area. Many oil seeps, gas seeps, and petroliferous beds occur in the Katalla-Yakataga area. Exploration has been without success, however, probably because of complex structure of asymmetric folds and north-dipping thrust faults, and the failure to find suitable reservoir rocks. Though little is known of the geology of the Bering Sea shelf, it should be considered for petroleum possibilities in view of its large size, possible extension across it of belts of late Mesozoic rocks, and possible Tertiary deposition along its outer edge. Except for the southern part of the Brooks Range, most of the Arctic Slope province, an area of about 125,000 sq mi, may be considered potentially petroliferous. It is underlain by calcareous and clastic miogeosynclinal rocks of Paleozoic and early Mesozoic ages and by clastic rocks of middle and late Mesozoic age. Structure, complex in the Brooks Range, decreases in complexity northward across the foothill belts and the Arctic Coastal Plain. Significant gas and oil reserves have been found in Cretaceous rocks. Gently deformed marine and nonmarine clastic Tertiary rocks crop out in limited areas in the northeastern part of the province. The Yukon-Koyukuk province in west-central Alaska has an area of about 85,000 sq mi. Large parts of the province are underlain by unmetamorphosed mid-Cretaceous rocks that may be locally petroliferous, although the great bulk of these rocks appear to be high-rank graywacke with poor reservoir characteristics. The Yukon-Porcupine province, an area of 15,000 sq mi, is underlain by a thick sequence of moderately deformed, largely unmetamorphosed Paleozoic and Mesozoic strata. Though no real evaluation can be made until test wells are drilled, the province appears to be relatively the most promising area in central Alaska.

TECHNOLOGY AND CULTURE Book Reviews 437 The Trans-Alaska Pipeline Controversy: Technology, Conservation, and the Frontier. By Peter A. Coates. Bethlehem, Pa.: Lehigh University Press; Cranbury, N.J.: Associated University Presses, 1991. Pp. 447; illustra­ tions, notes, bibliography, index. $57.50. There are pipes and then there are pipes. The Trans-Alaska Pipeline (TAP) must rank as one of the most monumental pipes in the history of the world. From Prudhoe Bay to Valdez, the TAP measures 800 miles in length. About half the pipe is elevated, and half buried in the ground as it wends its way south, forging over the Brooks Range before descending across the Yukon River past Fairbanks and then climbing over the Alaska Range before disgorging itself at Valdez, the now infamous port on Prince William Sound. At one point there were more than 28,000 workers out there in the wilderness, making the 100,000 welds it took to connect the joints of this tubular monster that now cuts the nation’s largest state in half like a Mississippi River of steel. That pipe was built by the Alyeska Pipeline Service Company, a consortium made up of this world’s largest and most powerful oil companies, including ARCO, Humble, and BP. It was finished in the summer of 1977, and since then we have heard little about it, that is, not until 1989, when a drunken ship captain grounded his tanker, the Exxon Valdez, on a reef, turning the Alaska coast black with oil. What is there to say about a pipe? A good deal indeed, judging from this thick volume written by Peter Coates. To be fair, Coates’s book is about more than just the TAP. In an effort to put the pipeline in historical perspective, Coates takes us back to the 19th century, to the time when the United States first acquired Alaska. Then the narrative moves forward in time to look at the role of technology and conserva­ tion in the history of the state. He covers the history of the Rampart Dam, which was never actually built, and of Project Chariot, a plan by the Atomic Energy Commission (AEC) to use nuclear explosives to blow a hole at the mouth of Ogotoruk Creek (over 100 miles north of the Arctic Circle) in order to turn the area into a harbor. Edward Teller— that tireless promoter of the control of nature—told an audience in 1959 that, if the AEC wanted to, it could “dig a harbor in the shape of a polar bear” (p. 121). Although the harbor was never built, when it comes to Alaska, Americans have tended to think big and arrogantly. And it was precisely this philosophy—that we can indeed do what we want with the natural world—that seems to have informed the TAP project from the start. Coates aims to use the pipeline controversy to uncover the meaning of the frontier forAlaska and forAmerican history more generally. What he finds is that supporters and defenders of the pipeline project (and the other technological projects that were planned for the state) invoked the rhetoric of the frontier to advance their respective causes. So Spiro Agnew, in defending the pipeline, recalled how we had 438 Book Reviews TECHNOLOGY AND CULTURE conquered the American West and its frontier back in the 19th century. Alaska was simply the logical extension of that frontier, and it too needed to be conquered. That promoters of the pipeline and others used such frontier rhetoric is not by itself all that surprising. Frontier ideology has long occupied a place at the center of American culture. Thus the book left me feeling rather disappointed. One is hard-pressed to say exactly what Coates is trying to tell us. This is because the book lacks a coherent focus. Coates’s foray into Alaska conservation history leading up to the TAP is not sufficiently well connected with the story of the TAP controversy itself. What is the real meaning and historical lesson of the pipeline project? It is difficult to say what Coates’s answer would be, but his emphasis on the frontier is not entirely misguided. He just does not go far enough...