Radiometric Dating of Marine Shells from the Bootlegger Cove Clay, Anchorage Area, Alaska

Schmoll, Henry R.; Szabo, B. J.; Rubin, Meyer; Dobrovolny, Ernest

doi:10.1130/0016-7606(1972)83[1107:rdomsf]2.0.co;2

Cited by 36 publications

(15 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Schmoll et al (1972) suggested that shell-bearing clays near Anchorage, between þ10 and þ14 m amsl and dating from 16.8 to 14.6 ka BP were formed during a marine transgression during an early post-glacial phase of eustatic sea-level rise, although Mann and Hamilton (1995) argue that glacio-isostatic depression resulted in the high stand. The shell-bearing sediments described by Schmoll et al (1972) extend to an elevation of þ36 m amsl, which led Reger and Pinney (1995) to argue that RSL was at least that high between 16.8 and 14.6 ka BP. Although the elevation of the high stand is unknown, peat at þ24 m amsl suggests that RSL in Cook Inlet was below that elevation by 16.2 to 14.2 ka BP (Rubin and Alexander, 1958).…”

Section: South-central Alaskamentioning

confidence: 97%

Post-glacial sea-level change along the Pacific coast of North America

Shugar

Walker

Lian

et al. 2014

Quaternary Science Reviews

125

View full text Add to dashboard Cite

a b s t r a c tSea-level history since the Last Glacial Maximum on the Pacific margin of North America is complex and heterogeneous owing to regional differences in crustal deformation (neotectonics), changes in global ocean volumes (eustasy) and the depression and rebound of the Earth's crust in response to ice sheets on land (isostasy). At the Last Glacial Maximum, the Cordilleran Ice Sheet depressed the crust over which it formed and created a raised forebulge along peripheral areas offshore. This, combined with different tectonic settings along the coast, resulted in divergent relative sea-level responses during the Holocene. For example, sea level was up to 200 m higher than present in the lower Fraser Valley region of southwest British Columbia, due largely to isostatic depression. At the same time, sea level was 150 m lower than present in Haida Gwaii, on the northern coast of British Columbia, due to the combined effects of the forebulge raising the land and lower eustatic sea level. A forebulge also developed in parts of southeast Alaska resulting in post-glacial sea levels at least 122 m lower than present and possibly as low as 165 m. On the coasts of Washington and Oregon, as well as south-central Alaska, neotectonics and eustasy seem to have played larger roles than isostatic adjustments in controlling relative sea-level changes.

show abstract

Section: South-central Alaskamentioning

confidence: 97%

Post-glacial sea-level change along the Pacific coast of North America

Shugar

Walker

Lian

et al. 2014

Quaternary Science Reviews

125

View full text Add to dashboard Cite

show abstract

“…Abbott and Brochmann, 2003;Cook et al, 2005;Dawson et al, 2014;Pruett and Winker, 2005) whose polymorphy has been shaped by rapid, dynamic geologic processes throughout the region (Hopkins, 1959(Hopkins, , 1973. The final formation of Cook Inlet as a geographic feature is believed to have occurred ∼14,000 years ago (Reger et al, 2007;Schmoll et al, 1999) and fossil evidence indicates immediate colonization of the region thereafter by Macoma (Schmoll et al, 1972). Cook Inlet is the most northerly site in the region with abundant benthic food supplies that occur in the absence of permanent sea or shore-fast ice during winter (Ruthrauff et al, 2013b).…”

Section: Discussionmentioning

confidence: 99%

Ways to be different: foraging adaptations that facilitate higher intake rates in a northerly-wintering shorebird compared to a low-latitude conspecific

Ruthrauff

Dekinga

Gill

et al. 2015

Journal of Experimental Biology

View full text Add to dashboard Cite

At what phenotypic level do closely related subspecies that live in different environments differ with respect to food detection, ingestion and processing? This question motivated an experimental study on rock sandpipers (Calidris ptilocnemis). The species' nonbreeding range spans 20 deg of latitude, the extremes of which are inhabited by two subspecies: C. p. ptilocnemis that winters primarily in upper Cook Inlet, Alaska (61°N) and C. p. tschuktschorum that overlaps slightly with C. p. ptilocnemis but whose range extends much farther south (∼40°N). In view of the strongly contrasting energetic demands of their distinct nonbreeding distributions, we conducted experiments to assess the behavioral, physiological and sensory aspects of foraging and we used the bivalve Macoma balthica for all trials. C. p. ptilocnemis consumed a wider range of prey sizes, had higher maximum rates of energy intake, processed shell waste at higher maximum rates and handled prey more quickly. Notably, however, the two subspecies did not differ in their abilities to find buried prey. The subspecies were similar in size and had equally sized gizzards, but the more northern ptilocnemis individuals were 10-14% heavier than their same-sex tschuktschorum counterparts. The higher body mass in ptilocnemis probably resulted from hypertrophy of digestive organs (e.g. intestine, liver) related to digestion and nutrient assimilation. Given the previously established equality of the metabolic capacities of the two subspecies, we propose that the high-latitude nonbreeding range of ptilocnemis rock sandpipers is primarily facilitated by digestive (i.e. physiological) aspects of their foraging ecology rather than behavioral or sensory aspects.

show abstract

“…14 000 YBP; Karlstrom , Schmoll et al . ) formed by retreating glaciers during Holocene warming (Schmoll et al . ).…”

Section: Discussionmentioning

confidence: 99%

“…) and promoted its colonization by M. balthica (Schmoll et al . ). Here we show that M. balthica from upper Cook Inlet possess unique attributes compared with M. balthica from other sites.…”

mentioning

confidence: 97%

Energetic solutions of Rock Sandpipers to harsh winter conditions rely on prey quality

Ruthrauff

Dekinga

Gill

et al. 2017

Ibis

View full text Add to dashboard Cite

Rock Sandpipers Calidris ptilocnemis have the most northerly non‐breeding distribution of any shorebird in the Pacific Basin (upper Cook Inlet, Alaska; 61°N, 151°W). In terms of freezing temperatures, persistent winds and pervasive ice, this site is the harshest used by shorebirds during winter. We integrated physiological, metabolic, behavioural and environmental aspects of the non‐breeding ecology of Rock Sandpipers at the northern extent of their range to determine the relative importance of these factors in facilitating their unique non‐breeding ecology. Not surprisingly, estimated daily energetic demands were greatest during January, the coldest period of winter. These estimates were greatest for foraging birds, and exceeded basal metabolic rates by a factor of 6.5, a scope of increase that approaches the maximum sustained rate of energetic output by shorebirds during periods of migration, but far exceeds these periods in duration. We assessed the quality of their primary prey, the bivalve Macoma balthica, to determine the daily foraging duration required by Rock Sandpipers to satisfy such energetic demands. Based on size‐specific estimates of M. balthica quality, Rock Sandpipers require over 13 h/day of foraging time in upper Cook Inlet in January, even when feeding on the highest quality prey. This range approaches the average daily duration of mudflat availability in this region (c. 18 h), a maximum value that annually decreases due to the accumulation of shore‐fast ice. Rock Sandpipers are likely to maximize access to foraging sites by following the exposure of ice‐free mudflats across the upper Cook Inlet region and by selecting smaller, higher quality M. balthica to minimize foraging times. Ultimately, this unusual non‐breeding ecology relies on the high quality of their prey resources. Compared with other sites across their range, M. balthica from upper Cook Inlet have relatively light shells, potentially the result of the region's depauperate invertebrate predator community. Given the delicate balance between environmental and prey conditions that currently make Cook Inlet a viable wintering area for Rock Sandpipers, small variations in these variables may affect the suitability of the site in the future.

show abstract

Radiometric Dating of Marine Shells from the Bootlegger Cove Clay, Anchorage Area, Alaska

Cited by 36 publications

References 0 publications

Post-glacial sea-level change along the Pacific coast of North America

Post-glacial sea-level change along the Pacific coast of North America

Ways to be different: foraging adaptations that facilitate higher intake rates in a northerly-wintering shorebird compared to a low-latitude conspecific

Energetic solutions of Rock Sandpipers to harsh winter conditions rely on prey quality

Contact Info

Product

Resources

About