1,000 Years of House Change at Cape Espenberg, Alaska: A Case Study in Horizontal Stratigraphy

2013 ◽  
Vol 78 (3) ◽  
pp. 433-455 ◽  
Author(s):  
John Darwent ◽  
Owen K. Mason ◽  
John F. Hoffecker ◽  
Christyann M. Darwent

AbstractCape Espenberg is on the farthest southwestern extent of Kotzebue Sound, Alaska, just above the Arctic Circle, and is a peninsula composed of a series of dune-covered beach ridges. As part of a larger research initiative, extensive mapping to record all cultural features and characterize the topography of approximately 1 km2on the southeastern terminus of the cape was undertaken in 2007 and 2010. The primary purpose of this mapping was to explore the use of the cape for the past 1,200 years using one of the unique aspects of beach-ridge archaeology: horizontal stratigraphy. There were 11 intervals of beach ridge/dune development, and with the exception of one truncated ridge and the modern ridge, Thule-Iñupiaq people built semi-subterranean winter houses on each ridge. A total of 117 house depressions along with related cache pits, artifact scatters, whale bone, and hearths were identified; distribution of house forms indicate that Cape Espenberg has had an unbroken stream of cultural continuity. However, in terms of house architecture and community patterning, it appears that there has been a reduction of certain architectural components over time. Houses also occur more frequently in isolated contexts. Both aspects are coincident with the onset of the Little Ice Age.

2016 ◽  
Vol 85 (3) ◽  
pp. 347-357 ◽  
Author(s):  
Marie-Claude Fortin ◽  
Konrad Gajewski

A study of chironomid remains in the sediments of Lake JR01 on the Boothia Peninsula in the Central Canadian Arctic provides a high-resolution record of mean July air temperatures for the last 6.9 ka. Diatom and pollen studies have previously been published from this core. Peak Holocene temperatures occurred prior to 5.0 ka, a time when overall aquatic and terrestrial biological production was high. Chironomid-inferred summer air temperatures reached up to 7.5°C during this period. The region of Lake JR01 cooled over the mid- to late-Holocene, with high biological production between 6.1 and 5.4 ka. Biological production decreased again at ∼2 ka and the rate of cooling increased in the past 2 ka, with coolest temperatures occurring between 0.46 and 0.36 ka, coinciding with the Little Ice Age. Although biological production increased in the last 150 yr, the reconstructed temperatures do not indicate a warming during this time. During transitions, either warming or cooling, chironomid production increases, suggesting an ecosystem-level response to climate variability, seen at a number of lakes across the Arctic.


2014 ◽  
pp. 145-155 ◽  
Author(s):  
Abdolmajid Naderi Beni ◽  
Hamid Lahijani ◽  
Morsen Pourkerman ◽  
Rahman Jokar ◽  
Muna Hosseindoust ◽  
...  

2007 ◽  
Vol 44 (9) ◽  
pp. 1215-1233 ◽  
Author(s):  
Johannes Koch ◽  
John J Clague ◽  
Gerald D Osborn

The Little Ice Age glacier history in Garibaldi Provincial Park (southern Coast Mountains, British Columbia) was reconstructed using geomorphic mapping, radiocarbon ages on fossil wood in glacier forefields, dendrochronology, and lichenometry. The Little Ice Age began in the 11th century. Glaciers reached their first maximum of the past millennium in the 12th century. They were only slightly more extensive than today in the 13th century, but advanced at least twice in the 14th and 15th centuries to near their maximum Little Ice Age positions. Glaciers probably fluctuated around these advanced positions from the 15th century to the beginning of the 18th century. They achieved their greatest extent between A.D. 1690 and 1720. Moraines were deposited at positions beyond present-day ice limits throughout the 19th and early 20th centuries. Glacier fluctuations appear to be synchronous throughout Garibaldi Park. This chronology agrees well with similar records from other mountain ranges and with reconstructed Northern Hemisphere temperature series, indicating global forcing of glacier fluctuations in the past millennium. It also corresponds with sunspot minima, indicating that solar irradiance plays an important role in late Holocene climate change.


2016 ◽  
Vol 10 (3) ◽  
pp. 1317-1329 ◽  
Author(s):  
Jakub Małecki

Abstract. Svalbard is a heavily glacier-covered archipelago in the Arctic. Dickson Land (DL), in the central part of the largest island, Spitsbergen, is relatively arid and, as a result, glaciers there are relatively small and restricted mostly to valleys and cirques. This study presents a comprehensive analysis of glacier changes in DL based on inventories compiled from topographic maps and digital elevation models for the Little Ice Age (LIA) maximum, the 1960s, 1990, and 2009/2011. Total glacier area has decreased by  ∼ 38 % since the LIA maximum, and front retreat increased over the study period. Recently, most of the local glaciers have been consistently thinning in all elevation bands, in contrast to larger Svalbard ice masses which remain closer to balance. The mean 1990–2009/2011 geodetic mass balance of glaciers in DL is among the most negative from the Svalbard regional means known from the literature.


2017 ◽  
Vol 13 (11) ◽  
pp. 1527-1537 ◽  
Author(s):  
Simon L. Pendleton ◽  
Gifford H. Miller ◽  
Robert A. Anderson ◽  
Sarah E. Crump ◽  
Yafang Zhong ◽  
...  

Abstract. Records of Neoglacial glacier activity in the Arctic constructed from moraines are often incomplete due to a preservation bias toward the most extensive advance, often the Little Ice Age. Recent warming in the Arctic has caused extensive retreat of glaciers over the past several decades, exposing preserved landscapes complete with in situ tundra plants previously entombed by ice. The radiocarbon ages of these plants define the timing of snowline depression and glacier advance across the site, in response to local summer cooling. Erosion rapidly removes most dead plants that have been recently exposed by ice retreat, but where erosive processes are unusually weak, dead plants may remain preserved on the landscape for decades. In such settings, a transect of plant radiocarbon ages can be used to construct a near-continuous chronology of past ice margin advance. Here we present radiocarbon dates from the first such transect on Baffin Island, which directly dates the advance of a small ice cap over the past two millennia. The nature of ice expansion between 20 BCE and ∼ 1000 CE is still uncertain, but episodic advances at ∼ 1000 CE, ∼ 1200, and  ∼ 1500 led to the maximum Neoglacial dimensions ~ 1900 CE. We employ a two-dimensional numerical glacier model calibrated using the plant radiocarbon ages ice margin chronology to assess the sensitivity of the ice cap to temperature change. Model experiments show that at least ∼ 0.44 °C of cooling over the past 2 kyr is required for the ice cap to reach its 1900 CE margin, and that the period from ∼ 1000 to 1900 CE must have been at least 0.25° C cooler than the previous millennium, results that agree with regional temperature reconstructions and climate model simulations. However, significant warming since 1900 CE is required to explain retreat to its present position, and, at the same rate of warming, the ice cap will disappear before 2100 CE.


The Holocene ◽  
2019 ◽  
Vol 30 (2) ◽  
pp. 289-299
Author(s):  
Tingwei Zhang ◽  
Xiaoqiang Yang ◽  
Qiong Chen ◽  
Jaime L Toney ◽  
Qixian Zhou ◽  
...  

A number of archives that span the past ~2000 years suggest that recent variability in hydroclimatic conditions that are influenced by the Asian monsoon in China are unusual in the longer term context. However, the lack of high-resolution precipitation records over this period hampered our ability to characterize and constrain the forcing mechanism(s) of the recent humidity variations. Here, we present the ratio of hematite to goethite (Hm/Gt) derived from the semiquantitative evaluation of the diffuse reflectance spectroscopic analysis as a reliable and effective precipitation proxy to reconstruct the humidity variations during the past 1400 years deduced from Tengchongqinghai Lake sediments, southwestern China. Hm/Gt varied synchronously with variations of Chinese temperature reconstructed from the historical documents and sunspot activity index over the past 1400 years. Critical periodicities of ~450 and ~250 years show that solar activity is the dominant control on precipitation change on centennial scales. However, the relationship determined from Hm/Gt in this study contradicts the stalagmite δ18O interpretations from different regions of China, which exhibit a more complex precipitation pattern that is influenced by the strength of westerly jet in addition to the Asian monsoon. The increased westerly jet during the ‘Little Ice Age’ (LIA) caused a humid climate in southern China and dry conditions in northern and western China.


1977 ◽  
Vol 7 (1) ◽  
pp. 63-111 ◽  
Author(s):  
George H. Denton ◽  
Wibjörn Karlén

Complex glacier and tree-line fluctuations in the White River valley on the northern flank of the St. Elias and Wrangell Mountains in southern Alaska and Yukon Territory are recognized by detailed moraine maps and drift stratigraphy, and are dated by dendrochronology, lichenometry,14C ages, and stratigraphic relations of drift to the eastern (123014C yr BP) and northern (198014C yr BP) lobes of the White River Ash. The results show two major intervals of expansion, one concurrent with the well-known and widespread Little Ice Age and the other dated between 2900 and 210014C yr BP, with a culmination about 2600 and 280014C yr BP. Here, the ages of Little Ice Age moraines suggest fluctuating glacier expansion between ad 1500 and the early 20th century. Much of the 20th century has experienced glacier recession, but probably it would be premature to declare the Little Ice Age over. The complex moraine systems of the older expansion interval lie immediately downvalley from Little Ice Age moraines, suggesting that the two expansion intervals represent similar events in the Holocene, and hence that the Little Ice Age is not unique. Another very short-lived advance occurred about 1230 to 105014C yr BP. Spruce immigrated into the valley to a minimum altitude of 3500 ft (1067 m), about 600 ft (183 m) below the current spruce tree line of 4100 ft (1250 m), at least by 802014C yr BP. Subsequent intervals of high tree line were in accord with glacier recession; in fact, several spruce-wood deposits above current tree line occur bedded between Holocene tills. High deposits of fossil wood range up to 76 m above present tree line and are dated at about 5250, 3600 to 3000, and 2100 to 123014C yr BP. St. Elias glacial and tree-line fluctuations, which probably are controlled predominantly by summer temperature and by length of the growing and ablation seasons, correlate closely with a detailed Holocene tree-ring curve from California, suggesting a degree of synchronism of Holocene summer-temperature changes between the two areas. This synchronism is strengthened by comparison with the glacier record from British Columbia and Mt. Rainier. Likewise, broad synchronism of Holocene events exists across the Arctic between the St. Elias Mountains and Swedish Lappland. Finally, two sequences from the Southern Hemisphere show similar records, in so far as dating allows. Hence, we believe that a preliminary case can be made for broad synchronism of Holocene climatic fluctuations in several regions, although further data are needed and several areas, particularly Colorado and Baffin Island, show major differences in the regional pattern.


2013 ◽  
Vol 26 (19) ◽  
pp. 7586-7602 ◽  
Author(s):  
Flavio Lehner ◽  
Andreas Born ◽  
Christoph C. Raible ◽  
Thomas F. Stocker

Abstract The inception of the Little Ice Age (~1400–1700 AD) is believed to have been driven by an interplay of external forcing and climate system internal variability. While the hemispheric signal seems to have been dominated by solar irradiance and volcanic eruptions, the understanding of mechanisms shaping the climate on a continental scale is less robust. In an ensemble of transient model simulations and a new type of sensitivity experiments with artificial sea ice growth, the authors identify a sea ice–ocean–atmosphere feedback mechanism that amplifies the Little Ice Age cooling in the North Atlantic–European region and produces the temperature pattern suggested by paleoclimatic reconstructions. Initiated by increasing negative forcing, the Arctic sea ice substantially expands at the beginning of the Little Ice Age. The excess of sea ice is exported to the subpolar North Atlantic, where it melts, thereby weakening convection of the ocean. Consequently, northward ocean heat transport is reduced, reinforcing the expansion of the sea ice and the cooling of the Northern Hemisphere. In the Nordic Seas, sea surface height anomalies cause the oceanic recirculation to strengthen at the expense of the warm Barents Sea inflow, thereby further reinforcing sea ice growth. The absent ocean–atmosphere heat flux in the Barents Sea results in an amplified cooling over Northern Europe. The positive nature of this feedback mechanism enables sea ice to remain in an expanded state for decades up to a century, favoring sustained cold periods over Europe such as the Little Ice Age. Support for the feedback mechanism comes from recent proxy reconstructions around the Nordic Seas.


2020 ◽  
Author(s):  
Jesús Alcalá Reygosa ◽  
Néstor Campos ◽  
Melaine Le Roy ◽  
Bijeesh Kozhikkodan Veettil ◽  
Adam Emmer

<p>The Little Ice Age (LIA) occurred between CE 1250 and 1850 and is considered a period of moderate cold conditions, especially recorded in the northern hemisphere. Numerous recent studies provide robust evidence of glacier advances worldwide during the LIA and a dramatic retreat since then. These studies combined investigation of moraine records, paintings, topographical and glaciological measurements as well as multitemporal aerial and terrestrial photographs and satellite images. For instance, post-LIA glaciers retreat amounts ~60 % in the Alps (Paul et al., 2020), ~88 % in the Pyrenees (Rico et al., 2016) and 89 % in the Bolivian Andes (Ramírez et al., 2001). However, there is scarce knowledge in Mexico about the glacier changes since the LIA. The reconstructions are limited to the Iztaccíhualt volcano where Schneider et al. (2008) established a glacier retreat of 95 %.</p><p>Here, we reconstruct the glacier evolution since the LIA to CE 2015 of the Mexican highest ice-capped volcano: Pico de Orizaba (19° 01´ N, 97° 16´W, 5,675 m a.s.l.). Due to Pico de Orizaba is in the outer Tropic, the most plausible scenario is a glacier evolution similar to the Bolivian Andes and especially to the Iztaccíhualt volcano. To carry out this research, we mapped the glacier area during the LIA, based on moraine record, and the area during 1945, 1958, 1971, 1988, 1994, 2003 and 2015 using a previous map elaborated by Palacios and Vázquez-Selem (1996), aerial orthophotographs and satellite images. The geographical mapping and the calculus of area, minimum altitude and volume of the glacier were generated with the software ArcGIS 10.2.2. The results show that glacier area retreated 92% between the LIA (8.8 km<sup>2</sup>) and 2015 (0.67 km<sup>2</sup>), being a drastic glacier loss in agreement with the Bolivian Andes and Iztaccíhualt. Therefore, mexican glaciers have experienced the major shrunk since LIA that implies a highly sensitive reaction to global warming.</p><p>This research was supported by the Project UNAM-DGAPA-PAPIIT grant IA105318.</p><p>References</p><p>Palacios, D., Vázquez-Selem, L. 1996. Geomorphic effects of the retreat of Jamapa glacier, Pico de Orizaba volcano (Mexico). Geografiska Annaler, Series A, Physical Geography 78, 19-34.</p><p>Paul F., Rastner P., Azzoni R.S., Diolaiuti G., Fugazza D., Le Bris R., Nemec J., Rabatel A., Ramusovic M., Schwaizer G., and Smiraglia C. 2020. Glacier shrinkage in the Alps continues unabated as revealed by a new glacier inventory from Sentinel-2 https://doi.org/10.5194/essd-2019-213.</p><p>Ramírez, E., Francou, B., Ribstein, P., Descloitres, M., Guérin, R., Mendoza, J., Gallaire, R., Pouyaud, B., Jordan, E. 2001. Small glaciers disappearing in the tropical Andes: a case study in Bolivia: Glaciar Chacaltaya (16° S). Journal of Glaciology 47 (157), 187-194.</p><p>Rico I., Izagirre E., Serrano E., López-Moreno J.I., 2016. Current glacier area in the Pyrenees : an updated assessment 2016. Pirineos 172, doi: http://dx.doi.org/10.3989/Pirineos.2017.172004.</p><p>Schneider, D., Delgado-Granados, H., Huggel, C., Kääb, A. 2008. Assessing lahars from ice-capped volcanoes using ASTER satellite data, the SRTM DTM and two different flow models: case study on Iztaccíhuatl (Central Mexico). Natural Hazards and Earth System Sciences 8, 559-571.</p><p> </p><p> </p>


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