Southeast Alaska: a Prime Candidate Allied Area for the NSF MARGINS Program

Authors

John M. Jaeger(jmj5@lehigh.edu)
241 Williamson Hall, P.O. Box 112120, Dept of Geology, University of Florida, Gainesville, FL 32611, (352) 846-1381, FAX: (352) 392-9294

Bernard Hallet (hallet@u.washington.edu)
Quaternary Research Center, University of Washington, Box 351360, Seattle, WA 98195-1360, Tel: (206) 543-1166, FAX: (206) 543-3836

Selection Criteria

Sediment is generated at extreme rates from rapid erosion of mountains in southeast Alaska (Fig. 1) due to intense tectonic and surficial processes.

Figure 1. Map of southeast Alaska continental margin. The largest current sediment sources to the Gulf of Alaska are the Copper River, and the Breaing and Malaspina Glaciers. Significant quantities of sediment also are trapped in coastal embayments. During glacial periods when glaciers terminate near the shelf break, sediment is transported to deep water via slope gullies and continental rise channels. Edge Site is location of active methan seep and authigenic carbonates. See Fig. 4 for seismic line YT-3 near Yakutat Bay. After Carlson et al. (1990, 1996). Bathymetry in meters.

Figure 1. Click to load larger image

The region features the highest coastal mountain range on earth; the Chugach and Wrangell-St. Elias mountains with elevations exceeding 5000 m within 18 km of the waters of the Pacific. The high range largely prevent Pacific storms from entering the northern latitudes (> 60 °N) of North America and induce heavy precipitation (2000-3000 mm y-1, most as snow; Wilson and Overland, 1987) that fuels some of the largest, most rapid, and most erosive valley glaciers on Earth (Hallet et al. 1996). Worldwide, sediment yield (as a measure of erosion) from glaciated basins exceeds those for glacier-free basins of comparable size. Moreover, estimated sediment yields for the glaciers along southern Alaska are unsurpassed (Fig. 2).

Figure 2. Sediment yields from glacially-dominant basins versus fluvial-dominated basins (after Hallet et al., 1996). The glacial basins (shown by the shaded pattern in the upper left quadrant of each figure; Alaskan basins are within the darker region) form a population distinct and essentially non-overlapping with those of all other major groups of basins: (A) partially-glaciated basins in Alaska; (B) British Columbia; (C) Himalayas. Glacial yields are also distinct for yields from a world-wide set of basins (D,E,F), including those identified as having the highest sediment yields by Milliman and Syvitski (1992).

Figure 2. Click to load larger image

For example, even for Papua New Guinea where sediment yields from the high-relief mountains are among the greatest in the world (103-104 tons/km2/y; Milliman, 1996), they are estimated to be at least an order of magnitude less than those for glaciated mountains in southern Alaska (105 tons/km2/y; Hallet et al. 1996). The rapidly growing crustal welt is being cut down by ice as fast as it grows (e.g. Bird, 1996), and these processes are likely linked to one another and to the hemispheric climate.

The large valley glaciers in southeastern Alaska also provide an ideal natural laboratory to examine and better understand the rate of generation and size distribution of sediments produced by glaciers that have much in common with Last Glacial Maximum (LGM) ice masses. As one of the principal objectives of MARGINS is to understand sediment production and delivery to the oceans though at least the last glacial interglacial cycle, sediment production in LGM-like glacier systems demands special attention. The main glaciers in the coastal Alaska mountains are similar in terms of size and dynamics, and hence their sediment yields are likely to be comparable, to the larger alpine glaciers worldwide that extended far down valley of their current positions during the LGM. Moreover, a number of glaciers in the area coalesce to form massive piedmont lobes (e.g. the Malaspina and Bering, Fig. 3) that represent perhaps the closest modern analogs to the temperate portions of the Laurentide and Fennoscandian ice sheets through much of the Quaternary.

Figure 3. False-color composite Landset photomosaic from August, 1978. Large piedmont glaciers (Bering and Malaspina) originate from Bagley Ice Field. The annial peak in fluvial sediment discharge is dominated by glacial melting and occurs during this time period.

Figure 3. Click to load larger image

By studying this region that is presently under the dominant influence of active glaciers in close proximity to the oceans , much can also be learned about one of the spectacular but little understood features of the marine sedimentary record, the abrupt increase in terrigenous sediment delivery to the oceans at the onset of the Pleistocene glacial age (Davies et al., 1977; Hay et al., 1988). For example, in the Barents Sea and Scandinavian offshore, slow deposition during the Miocene and Early Pliocene contrasts strikingly with the subsequent massive deposition (e.g. Riis, 1992; Vågnes et al., 1992; Riis and Fjeldskaar, 1992). Sedimentary wedges up to 2000 m in thickness are thought to have accumulated largely within the last 2.5 Myr. This contrast reflects "a dramatic increase in deposition rates along the shelf was related to glaciation of the Barents Sea and of Scandinavia" (Riis and Fjeldskaar, 1992, p. 165). The modes of sediment transfer and the spatio-temporal variation in transfer rates are also critical in deciphering the architecture of such sedimentary packages (Elverhøi et al., 1995).

A better understanding of the efficiency of glaciers in eroding landscapes and in producing sediments will not only contribute directly to MARGIN objectives, but will also do so indirectly by providing links to other disciplines because glacial erosion is central to diverse issues of interest to a broad scientific community. Temporal and spatial variations in rates of exhumation, as well as sedimentation, in many areas previously or currently glaciarized are key topics in diverse scenarios that link climate, tectonics, topography and sediment delivery to the oceans. For example, more rapid exhumation during the cooler climate of the Quaternary is expected to accelerate rock uplift driven not by tectonics, by buoyancy due to accelerated erosional unloading in alpine regions (e.g. Molnar and England, 1980). Another example relates to temporal variations in global rates of weathering of glacially eroded sediments on the continents, which may contribute to the cooling of the planet by drawing down atmospheric CO2, as inferred in an ocean-atmosphere model study of the large global variation in atmospheric CO2 through the last glaciation (Munhoven, 1997). Although this inference is highly controversial (Ludwig et al., 1999) and other mechanisms have been proposed, studies of contemporary chemical weathering rates in areas like southern Alaska where glacial sediments are weathering merit attention.

In addition to the extreme rates of erosion observed in southeastern Alaska, and to the existence of large glaciers that offer excellent opportunities to study erosion and sediment production by LGM-like alpine glaciers and ice sheets, this region has many other attributes that make it an excellent MARGINS study area:

Return to Top

Strong forcing that produces strong signals

The high sediment yields result from strong tectonic and climatic forcing, with uplift rates of several meters/1000 y, rates of crustal convergence with respect to central Alaska of several centimeters per year (Fig. 4; Sauber et al. 1997), and meters of precipitation per year.

Figure 4. Geodetic sites and horizontal vector velocities for southern Alaska (from Sauber et al., 1997). The vector velocities of sites with I-sigma errors in the components of less that 2mm/yr, relative to Fairbanks, are given with error ellipses representing regions of 95% condifence. The shaded regions (with year) indicate the rupture zones of major earthquakes this century. The NUVEL-IA predicted rate of motion of the Pacific plate relative to a fixed North American plate (52 mm/yr") is given by the vector in lower right corner. Faults (solid lines): brf=Border Range; cf=Contact; csef= Chugach -St. Elias; df= Denali; ff= Fairweather; pfz= Pamplona fault zone; tfz= Transition; mw= Mount Wrangell

Figure 4. Click to load larger image

The resulting temperate glaciers are arguably the largest temperate valley glaciers on Earth and they move at rates of hundreds of meters per year. Moreover, they have undergone tens of kilometers of advance and retreat from the coastal mountains onto the adjacent continental shelf during Pleistocene glacial periods. These advances have created distinct strata and unconformities on the shelf, slope, and abyssal plain (Carlson, 1989; Carlson et al., 1996). On shorter time scales (decades), the Bering Glacier, Hubbard Glacier and a number of the other large glaciers in the area have surged down valley and subsequently undergone rapid retreat, producing distinct event beds (Cowan et al., 1996; Jaeger and Nittrouer, 1999a). Intense tectonic activity results in frequent earthquakes (five earthquakes of M_s 7.0 or greater have occurred in this region since 1979). In 1964 the Prince William Sound Quake (M_w 9.2; moment magnitude)resulted in vertical ground displacements of ~ 10 m and a powerful tsunami (Plafker et al. 1994). Numerous sedimentary deposits created by this earthquake and others exist on land, and in fjord and shelf sediments (Reimnitz, 1972; Jaeger and Nittrouer, in press; Milliman et al., in press).

In addition to tectonically influenced deposits, paleoenvironmental information may be contained in coastal Alaskan sediments. The two requirements for development of a laminated sediment sequence containing high resolution paleoenvironmental data are met in the fjords and bays of Southern Alaska (cf. Kemp, 1996): 1) seasonal variations in sediment supply and biological activity and 2) environmental conditions that preserve laminated sediment from bioturbation. In coastal Alaska high sediment discharge from temperate glaciers coupled with tidal forcing produces an ultra high-resolution record where laminae representing daily deposition can be identified in marine sediment cores (Mackiewiczet al., 1984; Cowan and Powell, 1990; Cowan and Powell, 1991; Cowan et al., 1997; Jaeger and Nittrouer, 1999b).

Return to Top

Active sedimentation spanning source-to-sink environments

Rates of weathering of diverse rock types along the southern coast of Alaska seem to be the highest reported in the literature (Roche; 1994). Diverse processes actively move material downslope; they range from the frost-induced motion of individual rock fragments to large-scale mass movements (Meigs, 1998) that have spectacular proportions, particularly in recently deglaciated areas. Rates of sediment accumulation in fluvial drainages and coastal plains, coastal embayments, continental shelves, slopes, rises and abyssal plains are exceptionally high. Coastal plains are undergoing pronounced progradation at >5 km/ky (Molnia, 1983; Hayes and Ruby, 1996). The volume of sediment stored above sea level is relatively small, however, because it is largely confined to a narrow strip of coastal plain sandwiched between high mountains or glaciers and the Pacific ocean. This renders the transfer of sediments from source-to-sink rather direct in comparison with other MARGIN sites where this transfer involves, and is confounded by, considerable sediment storage on land.

Sediment accumulation rates in coastal embayments is the highest in the world, exceeding several meters/year (Powell and Molnia, 1989; Hunter, ). The continental shelf has experienced a maximum of 350 m of sediment accumulation during the Holocene, and annual rates range from <1 to >20 mm/y (Fig. 5) (Jaeger et al., 1998).

Figure 5. Holocene sediments thickness derived from seismic profiles (Milliman et al., in press). Thickness deposits located near major sediment sources (Copper River, Alsek River, Bering and Malaspina Glaciers). Thick deposits in Prince William Sound and southwest of Kayak Island demonstrat the westward advection of sediment by the Alaskan Coastal Current. Modern sediment accumulation matches Holocene trends (Jaeger et al., 1998).

Figure 5. Click to load larger image

Very few cores have been collected on the continental slope and rise to examine modern sediment accumulation. However, the presence of glacially derived gravely muds in the uppermost sections of cores suggests that little modern mud is accumulating on the slope, with the possible exception of southwest of Kayak Island where off-shelf transport of sediment is observed (Carlson et al., 1990; Jaeger et al., 1998). The Aleutian Trench is largely filled due to the increased terrigenous input during the Neogene, with the oldest trench fill being only 0.6 My. (von Huene et al., 1979). Sediment accumulation rates in the trench average 3500 m/My during glacial periods and 200-300 m/My during interglacials (von Huene et al., 1979). DSDP cores on the Alaskan Abyssal Plain (site 178) reveal 270 m of Plio-Pliestocene turbidites, ice-rafted debris, and hemipelagic sediment (Kulm et al., 1973). Average sediment accumulation rates on the abyssal plain during the past 0.6 My are 175m/My (Piper et al., 1973).

Return to Top

Active transfer among environments

Currently, sediment transfer is active from the coastal mountains to the adjacent continental shelf through fluvial transport and tidewater glacial melting, with subsequent dispersal of suspended sediment in the ocean (Powell and Molnia, 1989; Jaeger et al., 1998). Over 104 y time scales, sediment transfer to the continental slope, rise and Alaskan Abyssal Plain by glacial-marine processes is indicated by the presence of ice-rafted debris in gravity cores and DSDP Holes 178 and 180 (Kulm et al., 1973; Carlson et al., 1996). Active transfer of sediments from the shelf to the abyssal plain via gravity currents is indicated by pronounced trellised and dendritic gullies on the slope; canyons are small and infrequently observed (Carlson et al., 1996). The gullies merge to form larger channels that terminate on the abyssal plain and in the Aleutian Trench (Fig. 1).

Closed system

On individual drainage basin scales, many systems are closed, especially where individual glacial drainages terminate as tidewater glaciers in deep coastal fjords (Powell and Molnia, 1989; Jaeger and Nittrouer, 1999b). Because little modern sediment appears to be escaping onto the slope, the sediment from the Chugach and Wrangell-St. Elias mountains currently is accumulating in coastal plains, fjords, or on the continental shelf (Molnia, 1983; Jaeger et al., 1998). However, during glacial advances, massive glaciers from the Alaskan Peninsula to the Panhandle extended over parts of the shelf, and it is likely that they discharged sediment onto the continental slope, feeding the deep sea channels (Carlson et al., 1990).

High-resolution stratigraphic record

High sediment yields from the coastal mountains have existed since the late Miocene and have resulted in upwards of 5 km of Plio-Pliestocene glacial, glacial-marine, and marine deposits known as the Yakataga Formation, which formed at inner continental shelf to upper slope depths (Eyles et al, 1991). This formation represents one of the longest and most complete records of late Cenozoic sedimentation in the world (Plafker and Addicott, 1976). The Yakataga Formation is exposed on land, and is found beneath the continental shelf (Fig. 6).

Figure 6. Seismic line YT-3 from the relatively undeformed Yakutat segment of the margin. See Fig. 1 for location. Formation identification based on control provided by nearby (~30 km) well on shelf. Plio-Pleistocene Yakataga Fm. is 1000-2200m thick in this section. Poul Creek Fm. is late Oligocene to Miocene maginal marine sediments. Kultieth Fm. is mid-late Eocene coastal marine sediments. Acoustic basement is early Eocene basalts (from Risely, 1993).

Figure 6. Click to load larger image

West of 142°W, the Yakataga formation is faulted and folded, but the eastern half of the shelf is largely undeformed (Bruns, 1985). The few wells drilled on the shelf were not sampled at a high enough frequency to discern the stratigraphic completeness of the Yakataga Formation underlying the shelf (Martin, 1993).

Return to Top

Presence of carbonate environments

Siliciclastic sediments dominate sediment accumulation on this margin, with shell lags on bathymetric highs being the most common occurrence of carbonates on the shelf (Carlson et al., 1977). However, authigenic carbonates have been discovered on accretionary ridges of the lower continental slope (Edge Site, Fig. 1) (Suess et al., 1998). These authigenic carbonates are found near cold seeps, where methane-rich porewater is released to the overlying water column. Similar authigenic carbonates are found worldwide on accretionary margins (see references in Suess et al., 1998).

Significant differences between the two sites

The extreme rates of weathering and erosion, the exceptional relief in close proximity to the coast, the minimal storage of sediments on land, and the dominant presence of massive glaciers make this margin unlike any of the focus sites.

Background data and scientific infrastructure

Considerable data are available about the geophysical and tectonic setting of the southern Alaska margin. According to the most comprehensive tectonic model of the Alaska syntaxis by Plafker et al. (1994), convergence of the Pacific, Kula and North American plates has been accompanied by exotic terrane accretion since the Mesozoic. Analysis of seismic refraction data obtained during the Trans-Alaska Crustal Transect (TACT) reveals the deep structure of the northwestern margin: subduction of the Kula plate in early mid-Tertiary, a period of extreme convergence, led to tectonic underplating of the Chugach and previously accreted terranes at a depth of 9 km, and the Pacific slab is shown to be subducting at lower crustal level (Fuis and Plafker, 1991). Driven by the Pacific plate, the Yakutat block, an oceanic terrane with significant sedimentary clastic cover, started subducting under North America to the north of the syntaxis in early Miocene as slip to the southeast was accommodated along the Fairweather and Transition faults. Reorientation of the Pacific plate motion along a more northerly displacement vector during the late-Miocene early-Pliocene led to increased compression along the southern continental margin.

Relative convergence of the North American and Pacific plates has been steady at 55 mm/y over the last 5 My. As the Yakutat block rides relatively passively on the Pacific plate (with only ~10 mm/y of relative motion between the two; Lahr and Plafker, 1980), compression is accommodated by ocean-verging structures within fold and thrust belts, offshore at the Pamplona zone and onshore at the Chugach- St. Elias fault zone, which is under current investigation by a number of researchers (e.g. Pavlis, Plafker, Sissons, and others). GPS measurements show that coastal Alaska is converging with central Alaska at 39 mm/y (Fig. 4; Sauber, 1999, pers. communication). The geometry of the syntaxis and plate motion vectors induce along-strike differences in the interaction between the Yakutat terrane and the North American plate. Nearly orthogonal collision accompanied by moderately steep subduction of the Yakutat terrane and the Pacific Plate to the northwest (as inferred from TACT data) has led to the moderate uplift of the Chugach mountains, localized deformation south of the margin at the Kayak Island zone, and andesitic volcanism in the Wrangell range to the north (Fuis and Plafker, 1991; Eastabrook et al., 1992). In contrast, convergence to the southeast and underthrusting of Yakutat rocks as far east as the Malaspina Fault translated into extreme uplift of the St. Elias mountains and dextral slip on the Border Range, Fairweather and possibly other faults (Eastabrook et al., 1992).

Substantial seismic and geodynamic data from the region and a lithospheric model are also available. The seismicity of the area, featuring large earthquakes and the well studied Yakataga seismic gap near Icy Cape, provides useful information about stresses, thickness and other characteristics of the lithosphere (Lahr, and Plafker, 1980.; Ma et al., 1990; Eastabrook et al., 1992.). Geologic data provide estimates of fault slip rates and principal stress orientations. Contemporary strains have been measured using geodimeters (Lisowski et al. 1987; Savage and Lisowski, 1991), very long baseline interferometry (Ma et al., 1990) and more recently by GPS (Sauber et al., 1997). Bird (1996) has used these data collectively (except for the relevant GPS data that posdate his study) to assess the validity of his simulations of Alaskan neotectonics. He modeled ongoing deformation and fault slip in the Alaska region with thin-plate finite element methods, and calculated time-averaged anelastic stresses and deformation fields, focusing on stress and deformation in plan-view (as a function of latitude and longitude).

In addition to these data on contemporary crustal deformation rates and structure being available, estimates can be made of deposition rates, and hence of denudation rates through the Pleistocene using the near-surface sediment on the continental shelf, as stated earlier. Also, a wealth of information about both rates of sedimentation and rates of subsidence exists due to extensive seismic surveys and a number of wells drilled for petroleum resource exploration in SE Alaska (Magoon, 1994; Plafker et al., 1994). This information, together with documentation of the stratigraphic record in the Yakataga Formation that is exposed on land (Eyles et al. 1991), documents the long term evolution of the southern Alaska margin.

Much is known about the geometry (ice thickness, as well as spatial extent), mass balance, dynamics, and sediment production of some of the glaciers in the area. For example, the Variagated Glacier is the surging glaciers that has been subject to the most comprehensive study to date in the world (e.g. Kamb, et al. 1985; Humphrey et al. 1986; Raymond, 1987; Raymond and Harrison, 1988). A team of researchers led by Raymond, Kamb and Harrison conducted this study; they found that during the surges, which occur periodically about every 20 y, peak ice velocities exceed 50 m/day and vast volumes of sediment emanate from the glacier during major glacial floods (e.g. Humphrey, 1987; Humphrey and Raymond, 1994). For the glaciers terminating in fjords, much has been learned about the processes controlling terminus retreat, iceberg production by glacier calving, sediment delivery at the glacier margin, and formation of characteristic sedimentary packages. The rapid retreat of Columbia glacier that started over a decade ago after a standstill nearly a century-long has been particularly well examined; a number of USGS and associated researchers were involved, including Meyer, Kamb, Rasmussen, Humphrey, Krimmel, Brown, Post, Pfeffer, etc. (Meier, 1994; Meier et al., 1994; Kamb et al. 1994). On a longer time scale, the history of repeated advances and retreats has been reported for a number of coastal glacier systems (e.g. Porter, 1989), most recently for the Bering Glacier (Wiles et al., 1999). As mentioned above, numerous studies have been conducted largely by Carlson, Hunter, Jaeger, Milliman, Molnia, Powell, and co-workers on sedimentary processes on the margin, especially near the Bering and Malaspina Glaciers, in coastal fjords (Prince William Sound, Icy, Yakutat, and Glacier Bays), and on the continental shelf.

Diverse useful images and data sets are available for the southern Alaska region, in addition to series of high quality aerial photographs taken by a number of agencies. The large scale of the glacier systems there makes them suitable for satellite imagery and for airborne laser altimetry (Echelmeyer, pers. communication, 1999; http://www.gi.alaska.edu/snowice/glacier9.html). Radar data have proved useful in reflecting major channels and other features of the subglacial topography at Malaspina glacier. and SAR interferometry has been utilized to define the spatial variation in ice surface velocity of a portion of the Bering Glacier (Fatland and Lingle, 1998).

Large-scale USGS topographic maps and digital elevation data are available for the area within the U.S.. Digital elevation models with a nominal resolution of ~90 m have been derived from standard topographic maps. Reconnaissance-scale geologic maps have been produced, and more detailed maps are being developed through individual research programs aimed at the structure and petrology of the area,

Because of the sparse population and lack of roads into the region, climatic and stream flow data are spotty. The longest continuous stream flow data in the Gulf region exist for Power Creek near Cordova which has been continuously monitored since 1948. Precipitation and other standard meteorological data are available for all cities along the coast from 1931 to the present. Oceanographic data is limited; continuous meteorological and wave buoy data have only been present over the past decade, but long-term time series of temperature and salinity in the Gulf of Alaska has been carried out for the past three decades (Royer, 1993).

Return to Top

Manageable logistics

The presence of the study area in the United States makes political considerations unnecessary. The whole area on land can be reached readily (1-2 hours) using small airplanes or helicopters from one of the coastal cities served by a commercial airport. The coastal embayments and Gulf waters are easily accessible during most months of the year (March-October), with accessibility only hampered in the winter by harsh sea conditions in the Gulf. Much of the region belongs to federal agencies that encourage scientific research in the area.

Anthropogenic influences

The Gulf of Alaska margin is sparsely populated. No rivers discharging into the northeastern Gulf of Alaska have been altered or dammed, and anthropogenic landscape disturbance has been minimal (e.g., logging in Prince William Sound).

Societal relevance

The Gulf of Alaska margin is one of the most seismically active regions in the world (see paragraph I), with a number of very large events occurring in the past half century. Co-seismic event strata and deposits (e.g., gravity flows, slumps, slides, landslides, liquefaction structures, tsunami deposits) have been documented around the Gulf and correlated with specific seismic events. This study area would provide additional information about co-seismic disturbances, including the generation of major tsunamis (Johnson et al., 1996), that could be adapted to more populous regions where large seismic events are possible but infrequent (i.e., Cascadia).

Potential to leverage resources for research

In the next five years, the Coastal Ocean Processes (CoOP) program (NSF, ONR, and NOAA) will be examining coastal oceanographic processes, including particulate transport and accumulation, along a buoyancy (i.e., freshwater) influenced coastline. Because of the large and distributive nature of freshwater input to the Gulf of Alaska, this region could be a potential study site. The massive inputs of fresh water and sediments into Prince William Sound are major players in the circulation and the ecosystem of this sound, which is worth noting in the context of a major research program that is planned for improving the understanding of the ecosystem of the Sound. This program is exceptional in a number of ways, including being designed to last perhaps as long as one hundred years; it is being developed and will be funded by the Exxon Valdez Oil Spill Trustee Council. Moreover, the National Park Service is interested in fostering research, particularly in the Wrangell-St. Elias National Park that includes the largest ice masses in the region and extends across the U.S./Canada border.

Return to Top

References

Bird, P., 1996, Computer simulations of Alaskan neotectonics. Tectonics, v. 15, n. 2, p. 225-236.

Bruns, T. R., 1985. Tectonics of the Yakutat Block, an allochthonous terrane in the northern Gulf of Alaska. U.S.G.S. Open-File Report n. 85-0013, 112 p.

Carlson, P. R., 1989, Seismic reflection characteristics of glacial and glacimarine sediment in the Gulf of Alaska and adjacent fjords. Marine Geology, v. 85, p. 391-416.

Carlson, P. R., Bruns, T. R. and Fisher, M. A., 1990. Development of slope valleys in the glacimarine environment of a complex subduction zone, Northern Gulf of Alaska. In: Glacimarine Environments: Processes and Sediments (Ed. by J.A. Dowdeswell and J.D. Scourse), Geol. Soc. Special Pub., 53, 139-153.

Carlson, P. R., Molnia, B. F., Kittleson, S. C., and Hampson, J. C., 1977. Distribution of bottom sediments on the continental shelf, northern Gulf of Alaska, Scale 1:500,000. U.S. Geol. Survey Misc. Field Stud. Map MF-876, 13 pp., 2 sheets.

Carlson, P. R., Stevenson, A. J., Bruns, T. R., Mann, D. M., and Huggett, Q., 1996. Sediment pathways in Gulf of Alaska from beach to abyssal plain. In: J.V. Gardner, M.E. Field, and D.C. Twichell, eds., Geology of the United States' seafloor; the view from GLORIA. Cambridge University Press, Cambridge, U.K., p. 255-277.

Cowan, E. A.., Carlson, P. R., Powell, R. D., 1996, The marine record of the Russell Fiord outburst flood, Alaska, U.S.A. Annals of Glaciology, v. 22, p. 194-199.

Cowan, E.A. and Powell, R. D., 1991. Ice-proximal sediment accumulation rates in a temperate glacial fjord, southeastern Alaska. In: Glacial Marine Sedimentation; Paleoclimatic Significance (Ed. by J.B. Anderson and G.M. Ashley), Geol. Soc. Am. Special Paper, 261, 61-73.

Cowan, E. A., and Powell, R. D., 1990, Suspended sediment transport and deposition of cyclically interlaminated sediment in a temperate glacial fjord, Alaska, U.S.A, in Dowdeswell, J.A., and Scourse, J.D., eds., Glacimarine Environments: Processes and Sediments: Geological Society of London, Special Publication 53, p. 75-89.

Cowan, E. A., Cai, J., Powell, R. D., Clark, J. D. and Pitcher, J. N., 1997, Temperate glacimarine varves: An example from Disenchantment Bay, Alaska. J. Sediment. Res., 67, 536-549.

Davies, T. A., Hay, W. W., Southam, J. R., and Worseley, T. R., 1977. Science, 197, 53-55.

Eastabrook, C.H., Nabelek, J., Lerner-Lam, A., 1992. Tectonic Model of the Pacific-North American Plate Boundary in the Gulf of Alaska from Broadland Analysis of the 1979 St. Elias, Alaska, Earthquake and Its Aftershocks, J. Geophys. Res. 97: 6587-6612.

Elverhøi, A., Svendsen, J. I., Solheim, A., Andersen, E. S., Milliman, J., Mangerud, J., and Hooke, R. L., 1995. Late Quaternary sediment yield from the High Arctic Svalbard area. J. Geol., 103: 1-17.

Eyles, C. H., Eyles, N. and Lagoe, M. B., 1991. The Yakataga Formation; A Late Miocene to Pleistocene record of temperate glacial marine sedimentation in the Gulf of Alaska. In: Glacial Marine Sedimentation; Paleoclimatic Significance (Ed. by J.B. Anderson and G.M. Ashley), Geol. Soc. Am. Special Paper, 261, 159-180.

Fatland D. R., and Lingle, C. S., 1998, Analysis of the 1993--95 Bering Glacier (Alaska) surge using differential SAR interferometry. Journal of Glaciology, Volume 44, 532-546.

Fuis, G., and Plafker, G., 1991. Evolution of Deep Structure Along the Trans-Alaska Crustal Transect, Chugach Mountains and Copper River Basin, Southern Alaska, J. Geophys. Res. 96: 4229-4253.

Hallet, B., Hunter, L. and Bogen, J., 1996. Rates of erosion and sediment evacuation by glaciers: A review of field data and their implications. Global and Planet. Change, 12, 213-235.

Hay, W. W., Sloan, J. L., and Wold, C., 1988. Mass/age distribution and composition of sediments on the ocean floor and the global rate of sediment subduction. J. Geophys. Res., v. 93, 14933-14940.

Hayes, M. O. and Ruby, C. H., 1996. Barriers of Pacific Alaska. In: Geology of Holocene Barrier Island Systems. (Ed. by R.A. Davis, Jr.) Springer-Verlag, New York. 395-433.

Humphrey, N. C., Raymond, C. F., and Harrison, W. D., 1986. Discharges of turbid water during mini-surges of Variegated Glacier, Alaska. Journal of Glaciology, 32(111), 195--207.

Humphrey, N. F. and Raymond, C. F., (1994). Hydrology erosion and sediment production in a surging glacier, Variegated Glacier, Alaska, 1982-83. Journal of Glaciology, 40(136), 539--552.

Humphrey, N. F., 1987. Basal hydrology of a surge-type glacier: observations and theory relating to Variegated Glacier. Ph.D. Dissertation, Department of Geological Sciences, University of Washington.

Hunter, L. E., 1994. Grounding-line systems of modern temperate glaciers and their effects on glacier stability. Ph.D. Dissertation, Department of Geology, Northern Illinois University, Dekalb, Illinois, USA, 467 pp.

Jaeger, J. M. and Nittrouer, C. A., 1999a. Marine record of surge-induced outburst floods from the Bering Glacier, Alaska. Geology, v. 27, p. 847-850.

Jaeger, J. M. and Nittrouer, C. A., in press. The formation of sedimentary strata along a glacially impacted, mountainous coastline, northeast Gulf of Alaska. Cont. Shelf Res.

Jaeger, J. M., and Nittrouer, C. A, 1999b. Sediment deposition in an Alaskan fjord: Controls on the formation and preservation of sedimentary structures in Icy Bay. J. Sediment. Res., v. 69, p. 1011-1026.

Jaeger, J. M., Nittrouer, C. A., Scott, N. D., and Milliman, J. D., 1998. Sediment accumulation along a glacially impacted mountainous coastline: Northeast Gulf of Alaska. Bas. Res., v. 10, p. 155-173.

Johnson, J., Satake, K., Holdahl, S., Sauber, J., 1996. "The 1964 Prince William Sound Earthquake: Joint Inversion of Tsunami and Geodetic Data," J. Geophys. Res., 101 (B1), 523-532.

Kamb, B., Engelhardt, E., Fahnestock, M. A., Humphrey, N., Meier, M., and Stone, D., 1994: Mechanical and hydrologic basis for the rapid motion of a large tidewater glacier, 2. Interpretation. Journal of Geophysical Research, 99 (B8):15,231-15,244.

Kamb, W. B., Raymond, C. F., Harrison, W. D., Engelhardt, H., Echelmeyer, K. A., Humphrey, N., Brugman, M. M., and Pfeffer, W. T., 1985. Glacier surge mechanisms: 1982-83 surge of Variegated Glacier, Alaska. Science, 227(4686), 469--479.

Kulm, L. V. D., von Huene, R., et. al., 1973. Initial reports of the Deep Sea Drilling Project, covering Leg 18 of the cruises of the drilling vessel Glomar Challenger, Honolulu, Hawaii to Kodiak, Alaska May-July 1971. Initial Reports of the Deep Sea Drilling Project, v. 18, 1077 p.

Lahr, J. and Plafker, G., 1980. Holocene Pacific-North American Plate Interaction in Southern Alaska: Implications For the Yakataga Seismic Gap, Geology, 8: 483-486.

Lisowski, M., Savage, J. C., and Burford, R. O., 1987. Strain accumulation across the Fairweather and Totschunda faults, Alaska. , J. Geophys. Res. 92: 11,552-11,560.

Ludwig, W., Amiotte-Suchet, P., and Probst, J., 1999, Enhanced chemical weathering of rocks during the last glacial maximum: a sink for atmospheric CO2?: Chemical Geology, v. 159, p. 147-161.

Ma, C., Sauber, J. M., Bell, L. J., Clark, T. A., Gordon, D., Himwich, W. E., and Ryan, J. W., 1990. Measurement Of Horizontal Motions in Alaska Using Very Long Baseline Interferometry, J. Geophys. Res. 95: 21,991-22,011.

Mackiewicz, N. E., Powell, R. D., Carlson, P. R., and Molnia, B. F., 1984. Interlaminated ice-proximal glacimarine sediments in Muir Inlet, Alaska. Mar. Geol. 57: 113-147.

Magoon III, L. B., 1994. Petroleum resources in Alaska. The Geology of North America: V. G-1, The Geology of Alaska, Geological Society of America: 905-936.

Martin, G. C., 1993. Lithostratigraphy. In: Risely, D.E., et al., eds., Geologic Report for the Gulf of Alaska planning area. Mineral Management Service Report 92-0065, p. 63-98.

Meier, M. F., 1994. Columbia Glacier during rapid retreat: interactions between glacier flow and iceberg calving dynamics. Proceedings, Workshop on the Calving Rate of West Greenland Glaciers in Response to Climate Change, N. Reeh (Ed). Danish Polar Center, Copenhagen. 171 p.

Meier, M., Lundstrom, S., Stone, D., Kamb, B., Engelhardt, H., Humphrey, N. Dunlap, W. W., Fahnestock, M., Krimmel, R. M., and Walters, R., 1994. Mechanical and hydrologic basis for the rapid motion of a large tidewater glacier, 1. Observations. Journal of Geophysical Research, 99(B8):15,219-15,229.

Meigs, A., 1998. Bedrock Landsliding Accompanying Deglaciation: Three Possible Examples From the Chugach/St. Elias Range, Alaska. AGU Fall 1998 Meeting supplement to Eos Transactions of the AGU, 79, (45):F337.

Milliman, J. D., 1996. Sediment discharge to the ocean from small mountainous rivers; the New Guinea example. Geo-Marine Letters, v. 15, p. 127-133.

Milliman, J. D., Scott, N. & Stocks, D., in press. Holocene sediment thickness on the Copper River Delta, Alaska. J. Geol.

Molnar, P. and England, P., 1990. Late Cenozoic uplift of mountain ranges and global climate change: chicken or egg? Nature, 346, (6279): 29-34.

Molnia, B. F., 1979. Sedimentation in Coastal Embayments, Northeastern Gulf of Alaska. Offshore Technology Conference paper 3435.

Molnia, B. F., 1983. Sub-arctic glacial marine sedimentation-NE Gulf of Alaska. In: B.F. Molnia, ed. Glacial Marine Sedimentation. Plenum, New York, pp. 94-144.

Munhoven, G., 1997. Modeling Glacial-Interglacial Atmospheric CO2 Variations: The Role of Continental Weathering, Doctoral dissertation, Universite de Liege, Belgium.

Piper, D. J. W., von Huene, R., Duncan, J. R., 1973. Late Quaternary Sedimentation in the Active Eastern Aleutian Trench. Geology, v. 1, n. 1, p. 19-22.

Plafker, G., and Addicott, W. O., 1976. Glaciomarine deposits of Miocene through Holocene age in the Yakataga Formation along the Gulf of Alaska margin, Alaska. U.S.G.S. Open-File Report n. 76-0084, 45 p.

Plafker, G., Moore, C., and Winkler, G., 1994. Geology of the southern Alaska Margin, in The Geology of North America: V. G-1, The Geology of Alaska, Geological Society of America: 389-449.

Porter, S. C., 1989. Late Holocene cycles of advance and retreat of the fjord glacier system in Icy Bay, Alaska. Arctic Alpine Res., 1: 364-379.

Powell, R. D., and Molnia, B. F., 1989. Glacialmarine sedimentary processes, facies, and morphology of the south-southeast Alaska shelf and fjords. Mar. Geol. 85:359-390.

Raymond, C. F., 1987. How do glaciers surge? a review. Journal of Geophysical Research, 92(B9), 9121--9134.

Raymond, C. F. and Harrison, W. D., 1988. Evolution of Variegated Glacier, Alaska, U. S. A., prior to its surge. Journal of Glaciology, 34(117), 1--16.

Reimnitz, E., 1972. Effects in the Copper River Delta. In: The Great Alaska Earthquake of 1964: Oceanography and Coastal Engineering, NAS Pub. 1605, Washington, D.C., 290-302.

Riis, F., 1992. Dating and measuring of erosion , uplift and subsidence in Norway and the Norwegian shelf in glacial periods. Norsk. Geol. Tidsskr., 72: 325-331.

Riis, F., and Fjeldskaar, W., 1992. On the magnitude of the Late Tertiary and Quaternary erosion and its significance for the uplift of Scandinavia and the Barents Sea. In: R.M. Larsen, H. Brekke, B.T. Larsen and E. Talleraas (Editors), Structural and Tectonic Modeling and its Application to Petroleum Geology. Elsevier, Amsterdam. NPF Special Publication 1: 163-185.

Risely, D. E., 1993. Seismic Stratigraphy. In: Risely, D.E., et al., eds., Geologic Report for the Gulf of Alaska planning area. Mineral Management Service Report 92-0065, p. 17-44.

Roche, J. W., 1994. Lithologic controls on rapid frost-induced breakdown of rock, Icy Bay, Alaska. 1994 Annual American Geological Society Meeting, Seattle, WA. Abstract.

Royer, T. C., 1993. High-latitude oceanic variability associated with the 18.6-year nodal tide. J. Geop. Res., 98:4639-4644.

Sauber, J., McClusky, S. and King, R., 1997 "Relation of Ongoing Deformation Rates to the Subduction Zone Process in Southern Alaska", Geophys. Res. Letters, 24(22), 2853-2856.

Savage, J.C. and Lisowski, M., 1991. Strain accumulation along the Denali fault at the Nenana River and Delta River crossings, Alaska. J. Geophys. Res.: 96: 14,481-14,492.

Suess, E., et al., 1998. Fluid venting in the eastern Aleutian subduction zone. JGR, B, Solid Earth and Planets, v. 103, n. 2, p. 2597-2614.

Vågnes, E., Faleide, J.I., and Gudlaugsson, S. T., 1992. Glacial erosion and tectonic uplift in the Barents Sea. Norsk. Geol. Tidsskr., 72: 333-338.

von Huene, R., Shor, G.G. Jr., and Wagemen, J., 1979. Continental margins of the eastern Gulf of Alaska, and boundaries of tectonic plates. Watkins, J. S., Montadert, L., and Dickerson, P. W., eds., Geological and geophysical investigations of continental margins. AAPG Memoir n. 29, p. 273-290.

Wiles, Gregory C., Post, Austin, Muller, Ernest H., and Molnia, Bruce F., 1999. Dendrochronology and Late Holocene History of Bering Piedmont Glacier, Alaska. Quat. Res. 52, 185-195.

Wilson, J.G. and J.E. Overland, 1987. Meteorology. In: D.W. Hood and S.T. Zimmerman, eds., The Gulf of Alaska: Physical environment and biological resources. Nat. Ocean. Atmos. Adm., U.S. Dep. Commerce., pp. 31-56.

Return to Top