scholarly journals Little Ice Age glacial geomorphology and sedimentology of Portage Glacier, South-Central Alaska

Finisterra ◽  
2012 ◽  
Vol 44 (87) ◽  
Author(s):  
João Santos ◽  
Carlos Córdova
Keyword(s):  
Little Ice Age ◽  
Ice Sheets ◽  
Glacier Retreat ◽  
Ice Age ◽  
Glacial Geomorphology ◽  
South Central ◽  
Glacier Valley ◽  
Glacial Landforms ◽  
Basal Till ◽  
Insight Into

The study of glacial landforms and deposits is important, as it is difficult to observe processes under modern glaciers and ice-sheets. Thus landscapes and sediments that are the product of present glaciation can give insight into processes that occurred during  pleistocene times. This study investigates the genesis of little ice age glacial landforms present in portage Glacier, South-central Alaska. The present day moraine morphology and sedimentology in portage Glacier valley reveals the presence of two types of till and moraines. The clast-rich sandy diamicton present on the 1852 moraine is interpreted to be a basal till indicating this feature is a push moraine representing an advance or a standstill position of portage Glacier in 1852. The moderately sorted gray sandy boulder gravel present on the 1900 and 1922 moraines is interpreted to be an ice-marginal deposit (ablation till) with a mixture of supraglacial and glaciofluvial sediments deposited by slumping and stream sorting processes. All of these features are interpreted to be ablation moraines representing glacier retreat and moraine building in 1900 and1922.

scholarly journals Skaftafellsjökull, Iceland: glacial geomorphology recording glacier recession since the Little Ice Age

2017 ◽  
Vol 13 (2) ◽  
pp. 358-368 ◽  
Author(s):  
David J. A. Evans ◽  
Marek Ewertowski ◽  
Chris Orton
Keyword(s):  
Little Ice Age ◽  
Ice Age ◽  
Glacial Geomorphology ◽  
Glacier Recession

Drastic glacier retreat at Pico de Orizaba (19º N, Mexico) since the Little Ice Age

2020 ◽  
Author(s):  
Jesús Alcalá Reygosa ◽  
Néstor Campos ◽  
Melaine Le Roy ◽  
Bijeesh Kozhikkodan Veettil ◽  
Adam Emmer
Keyword(s):  
Little Ice Age ◽  
Satellite Images ◽  
Physical Geography ◽  
Glacier Retreat ◽  
Ice Age ◽  
Glacier Area ◽  
Tropical Andes ◽  
Bolivian Andes ◽  
The Alps

<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>

Little Ice Age Evidence from a South-Central North American Ice Core, U.S.A.

1996 ◽  
Vol 28 (1) ◽  
pp. 35 ◽  
Author(s):  
D. L. Naftz ◽  
R. W. Klusman ◽  
R. L. Michel ◽  
P. F. Schuster ◽  
M. M. Reddy ◽  
...  
Keyword(s):  
North American ◽  
Little Ice Age ◽  
Ice Core ◽  
Ice Age ◽  
South Central

scholarly journals Distribución espacial y temporal de glaciares, glaciares cubiertos y glaciares rocosos durante la última deglaciación en el valle de La Bonaigua (Pirineo Central)

2020 ◽  
Vol 46 (2) ◽  
pp. 413-446
Author(s):  
J. Ventura-Roca
Keyword(s):  
High Resolution ◽  
Little Ice Age ◽  
Ice Age ◽  
Lidar Data ◽  
Forest Environment ◽  
Digital Elevation ◽  
Rock Glaciers ◽  
Elevation Model ◽  
Glacial Landforms ◽  
Central Pyrenees

The application of the paleogeographic method to the study of glacial landforms and rock glaciers allows their morphometric and sedimentological characterization, the establishment of a detailed morphostratigraphic sequence and a chronological proposal for the identified glacial phases. This study analyzes 86 landforms (57 glacial deposits, 21 rock glaciers and 8 protalus ramparts) in the Bonaigua Valley (Noguera Pallaresa Basin, Central Pyrenees), with special attention to the differentiation between debris-covered glaciers and rock glaciers. Other subjects studied concerning rock glaciers are: distinguish its glacial or periglacial origin; the possible current activity of some landforms, and the detection of rock glaciers located at low altitudes (in the current forest environment) through the use of high-resolution digital elevation model (2x2 m) from LIDAR data. The chronological hypothesis elaborated by correlation with other high Pyrenean valleys (with absolute ages available) includes 7 phases (6 glacial phases and 1 periglacial phase) in which co-exist and/or evolve, in a paraglacial dynamic, glaciers, debris-covered glaciers and rock glaciers, and that we temporarily place between the end of the Oldest Dryas and the Little Ice Age.

scholarly journals Timing of Little Ice Age maxima and subsequent glacier retreat in northern Troms and western Finnmark, northern Norway

2020 ◽  
Vol 52 (1) ◽  
pp. 281-311
Author(s):  
J. R. Leigh ◽  
C. R. Stokes ◽  
D. J. A. Evans ◽  
R. J. Carr ◽  
L. M. Andreassen
Keyword(s):  
Little Ice Age ◽  
Glacier Retreat ◽  
Ice Age ◽  
Northern Norway

scholarly journals The evolution of the Patagonian Ice Sheet from 35 ka to the Present Day (PATICE)

2020 ◽  
Author(s):  
Bethan Davies ◽  
Keyword(s):  
Little Ice Age ◽  
Ice Sheet ◽  
Ice Age ◽  
Shelf Edge ◽  
Ice Streams ◽  
Glacial Geomorphology ◽  
Outlet Glacier ◽  
Southern South America ◽  
The Pacific ◽  
The Antarctic

<p>We present PATICE, a GIS database of Patagonian glacial geomorphology and recalibrated chronostratigraphic data. PATICE includes 58,823 landforms and 1,669 ages, and extends from 38°S to 55°S in southern South America. We use these data to generate new empirical reconstructions of the Patagonian Ice Sheet (PIS) and subsequent ice masses and ice-dammed palaeolakes at 35 ka, 30 ka, 25 ka, 20 ka, 15 ka, 13 ka (synchronous with the Antarctic Cold Reversal), 10 ka, 5 ka, 0.2 ka (synchronous with the “Little Ice Age”) and 2011 AD. At 35 ka, the PIS covered of 492.6 x10<sup>3 </sup>km<sup>2</sup>, had a sea level equivalent of ~1,496 mm, was 350 km wide and 2090 km long, and was grounded on the Pacific continental shelf edge. Outlet glacier lobes remained topographically confined and the largest generated the suites of subglacial streamlined bedforms characteristic of ice streams. The PIS reached its maximum extent at 33 – 28 ka from 38°S to 48°S, and earlier, around 47 ka from 48°S southwards. Net retreat from maximum positions began by 25 ka, with ice-marginal stabilisation at 21 – 18 ka, followed by rapid deglaciation. By 15 ka, the PIS had separated into disparate ice masses, draining into large ice-dammed lakes along the eastern margin, which strongly influenced rates of recession. Glacial readvances or stabilisations occurred at 14 – 13 ka, 11 ka, 5 – 6 ka, 1 – 2 ka, and 0.2 ka. We suggest that 20<sup>th</sup> century glacial recession is occurring faster than at any time documented during the Holocene. </p>

Recent woody invasion of wetlands on the Kenai Peninsula Lowlands, south-central Alaska: a major regime shift after 18 000 years of wet Sphagnum–sedge peat recruitment

2009 ◽  
Vol 39 (11) ◽  
pp. 2033-2046 ◽  
Author(s):  
Edward E. Berg ◽  
Kacy McDonnell Hillman ◽  
Roman Dial ◽  
Allana DeRuwe
Keyword(s):  
Little Ice Age ◽  
Regime Shift ◽  
Black Spruce ◽  
Ice Age ◽  
Woody Vegetation ◽  
Kenai Peninsula ◽  
South Central ◽  
Historical Aerial Photography ◽  
Dwarf Birch ◽  
Summer Temperatures

We document accelerating invasion of woody vegetation into wetlands on the western Kenai Peninsula lowlands. Historical aerial photography for 11 wetland sites showed that herbaceous area shrank 6.2%/decade from 1951 to 1968, and 11.1%/decade from 1968 to 1996. Corresponding rates for converting herbaceous area to shrubland were 11.5% and 13.7%/decade, respectively, and, for converting nonforest to forest, were 7.8% and 8.3%/decade, respectively. Black spruce ( Picea mariana (Mill.) BSP) forests on three wetland perimeters established since the Little Ice Age concluded in the 1850s. Dwarf birch shrubs at three wetland sites showed median apparent tree-ring age of 13 years, indicating recent shrub colonization at these sites. Peat cores at 24 wetland sites (basal peat ages 1840 – 18 740 calibrated years before present) indicated that these peatlands originated as wet Sphagnum –sedge fens with very little woody vegetation. Local meteorological records show a 55% decline in available water since 1968, of which one-third is due to higher summer temperatures and increased evapotranspiration and two-thirds is due to lower annual precipitation. These results suggest that wet Sphagnum–sedge fens initiating since the end of the Wisconsin glaciation began to dry in the 1850s and that this drying has greatly accelerated since the 1970s.

The changing extent of marine-terminating glaciers and ice caps in northeastern Svalbard since the ‘Little Ice Age’ from marine-geophysical records

The Holocene ◽  
2019 ◽  
Vol 30 (3) ◽  
pp. 389-401 ◽  
Author(s):  
Julian A Dowdeswell ◽  
Dag Ottesen ◽  
Valerie K Bellec
Keyword(s):  
Little Ice Age ◽  
Ice Age ◽  
Aerial Photographs ◽  
Past Century ◽  
Ice Caps ◽  
The Past ◽  
Covered Area ◽  
Data Coverage ◽  
Climatic Cooling ◽  
Glacial Landforms

Climate warming in Svalbard since the end of the ‘Little Ice Age’ early in the 20th century has reduced glacier extent in the archipelago. Previous attempts to reconstruct ‘Little Ice Age’ glacier limits have encountered problems in specifying the area of tidewater glacier advances because it is difficult to estimate the past positions of their marine termini. Multibeam echo-sounding data are needed to map past glacier extent offshore, especially in open-marine settings where subaerial lateral moraines cannot be used due to the absence of fjord walls. We use the submarine glacial landform record to measure the recent limits of advance of over 30 marine-terminating northeastern Svalbard glaciers and ice caps. Our results demonstrate that previous work has underestimated the ice-covered area relative to today by about 40% for northeastern Svalbard (excluding southeast Austfonna) because marine-geophysical evidence in the form of submarine terminal moraines was not included. We show that the recent ice extent was 1753 km2 larger than today over our full area of multibeam data coverage; about 5% of the total modern ice cover of Svalbard. It has often been assumed that moraine ridges located within a few kilometres of modern ice fronts in Svalbard represent either a ‘Little Ice Age’ maximum or relate to surge activity over the past century or so. In the marine environment of northeastern Svalbard, this timing can often be confirmed by reference to early historical maps and aerial photographs. Assemblages of submarine glacial landforms inshore of recently deposited terminal moraines suggest whether a recent advance may be a result of surging or ‘Little Ice Age’ climatic cooling relative to today. However, older terminal moraines do exist in the archipelago, as shown by radiocarbon and 10Be dating of Holocene moraine ridges.

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