Subdivision of Glacial Deposits in Southeastern Peru Based on Pedogenic Development and Radiometric Ages

2001 ◽  
Vol 56 (1) ◽  
pp. 31-50 ◽  
Author(s):  
Adam Y. Goodman ◽  
Donald T. Rodbell ◽  
Geoffrey O. Seltzer ◽  
Bryan G. Mark
Keyword(s):  
Chemical Weathering ◽  
Late Quaternary ◽  
Laboratory Data ◽  
Ice Age ◽  
Tropical Andes ◽  
Southern Peru ◽  
Ice Cap ◽  
Quaternary Glaciation ◽  
Quelccaya Ice Cap ◽  
Age Estimates

AbstractThe Cordillera Vilcanota and Quelccaya Ice Cap region of southern Peru (13°30′–14°00′S; 70°40′–71°25′W) contains a detailed record of late Quaternary glaciation in the tropical Andes. Quantification of soil development on 19 moraine crests and radiocarbon ages are used to reconstruct the glacial history. Secondary iron and clay increase linearly in Quelccaya soils and clay accumulates at a linear rate in Vilcanota soils, which may reflect the semicontinuous addition of eolian dust enriched in secondary iron to all soils. In contrast, logarithmic rates of iron buildup in soils in the Cordillera Vilcanota reflect chemical weathering; high concentrations of secondary iron in Vilcanota tills may mask the role of eolian input to these soils. Soil-age estimates from extrapolation of field and laboratory data suggest that the most extensive late Quaternary glaciation occurred >70,000 yr B.P. This provides one of the first semiquantitative age estimates for maximum ice extent in southern Peru and is supported by a minimum-limiting age of ∼41,520 14C yr B.P. A late glacial readvance culminated ∼16,650 cal yr B.P. in the Cordillera Vilcanota. Following rapid deglaciation of unknown extent, an advance of the Quelccaya Ice Cap occurred between ∼13,090 and 12,800 cal yr B.P., which coincides approximately with the onset of the Younger Dryas cooling in the North Atlantic region. Moraines deposited <394 cal yr B.P. in the Cordillera Vilcanota and <300 cal yr B.P. on the west side of the Quelccaya Ice Cap correlate with Little Ice Age moraines of other regions.

Past and future sky-island dynamics of tropical mountains: A model for two Geotrupes (Coleoptera: Geotrupidae) species in Oaxaca, Mexico

The Holocene ◽  
2020 ◽  
Vol 30 (10) ◽  
pp. 1462-1470 ◽  
Author(s):  
Alfonsina Arriaga-Jiménez ◽  
Bert Kohlmann ◽  
Lorenzo Vázquez-Selem ◽  
Yhenner Umaña ◽  
Matthias Rös
Keyword(s):  
Dynamic Process ◽  
Late Quaternary ◽  
Continuous Distribution ◽  
Ice Age ◽  
Mountain Range ◽  
Tropical Mountains ◽  
Quaternary Glaciation ◽  
Mountain System ◽  
Genetic Differentiation Of Populations ◽  
Sky Island

Recent collecting and taxonomic studies of dung beetles of the genus Geotrupes Latreille (Coleoptera: Geotrupidae) in the mountains of Oaxaca have evidenced the existence of a vicariant speciation pattern, where one species occupies the northern mountain system and the other one the southern mountain range. A study of this possible vicariant speciation mechanism is presented using a paleobiogeographic mapping analysis of both Geotrupes species distribution during Late Quaternary glaciation events. Based on these paleomaps a possible speciation mechanism (vicariant speciation) is suggested, in which one common ancestor (mother species) lived at the bottom of the Valle de Oaxaca (Oaxaca Valley) during the last local glacial maximum (LLGM, 21-17.5 kyr) and whose possible continuous distribution was broken into two (or more) separated areas on mountaintops as the climate became warmer toward the present. We propose that the fragmentation and isolation of habitats may have promoted genetic differentiation of populations resulting in vicariant speciation, as suggested by a sky-island dynamic process. The example of a possible effect of the Little Ice Age in the mountains of Oaxaca is also discussed. Finally, a projection is made into the XXII century, based on climatic modeling predictions. These last results suggest the possible disappearance of the sky-island dynamic process through the accelerated speed of climatic change.

scholarly journals Glacial areas, lake areas, and snow lines from 1975 to 2012: status of the Cordillera Vilcanota, including the Quelccaya Ice Cap, northern central Andes, Peru

2014 ◽  
Vol 8 (2) ◽  
pp. 359-376 ◽  
Author(s):  
M. N. Hanshaw ◽  
B. Bookhagen
Keyword(s):  
Satellite Images ◽  
Climate Changes ◽  
Spectral Unmixing ◽  
Limited Attention ◽  
Lake Area ◽  
Tropical Andes ◽  
The Past ◽  
Ice Cap ◽  
Downstream Communities ◽  
Quelccaya Ice Cap

Abstract. Glaciers in the tropical Andes of southern Peru have received limited attention compared to glaciers in other regions (both near and far), yet remain of vital importance to agriculture, fresh water, and hydropower supplies of downstream communities. Little is known about recent glacial-area changes and how the glaciers in this region respond to climate changes, and, ultimately, how these changes will affect lake and water supplies. To remedy this, we have used 158 multi-spectral satellite images spanning almost 4 decades, from 1975 to 2012, to obtain glacial- and lake-area outlines for the understudied Cordillera Vilcanota region, including the Quelccaya Ice Cap. Additionally, we have estimated the snow-line altitude of the Quelccaya Ice Cap using spectral unmixing methods. We have made the following four key observations: first, since 1988 glacial areas throughout the Cordillera Vilcanota (1988 glacial area: 361 km2) have been declining at a rate of 3.99 ± 1.15 km2 yr−1 (22 year average, 1988–2010, with 95% confidence interval (CI), n = 8 images). Since 1980, the Quelccaya Ice Cap (1980 glacial area: 63.1 km2) has been declining at a rate of 0.57 ± 0.10 km2 yr−1 (30 year average, 1980–2010, with 95% CI, n = 14). Second, decline rates for individual glacierized regions have been accelerating during the past decade (2000–2010) as compared to the preceding decade (1988–1999) with an average increase from 37.5 to 42.3 × 10−3 km2 yr−1 km−2 (13%). Third, glaciers with lower median elevations are declining at higher rates than those with higher median elevations. Specifically, glaciers with median elevations around 5200 m a.s.l. are retreating to higher elevations at a rate of ~1 m yr−1 faster than glaciers with median elevations around 5400 m a.s.l. Fourth, as glacial regions have decreased, 77% of lakes connected to glacial watersheds have either remained stable or shown a roughly synchronous increase in lake area, while 42% of lakes not connected to glacial watersheds have declined in area (58% have remained stable). Our new and detailed data on glacial and lake areas over 37 years provide an important spatiotemporal assessment of climate variability in this area. These data can be integrated into further studies to analyze inter-annual glacial and lake-area changes and assess hydrologic dependence and consequences for downstream populations.

Rapid Ice Margin Fluctuations during the Younger Dryas in the Tropical Andes

2000 ◽  
Vol 54 (3) ◽  
pp. 328-338 ◽  
Author(s):  
Donald T. Rodbell ◽  
Geoffrey O. Seltzer
Keyword(s):  
Younger Dryas ◽  
Late Glacial ◽  
Tropical Andes ◽  
Radiocarbon Dates ◽  
Peruvian Andes ◽  
Southern Peru ◽  
Ice Cap ◽  
The North ◽  
Glacier Advance ◽  
Lake Deposits

Radiocarbon dated lacustrine sequences in Perú show that the chronology of glaciation during the late glacial in the tropical Andes was significantly out-of-phase with the record of climate change in the North Atlantic region. Fluvial incision of glacial-lake deposits in the Cordillera Blanca, central Perú, has exposed a glacial outwash gravel; radiocarbon dates from peat stratigraphically bounding the gravel imply that a glacier advance culminated between ∼11,280 and 10,990 14C yr B.P.; rapid ice recession followed. Similarly, in southern Perú, ice readvanced between ∼11,500 and 10,900 14C yr B.P. as shown by a basal radiocarbon date of ∼10,870 14C yr B.P. from a lake within 1 km of the Quelccaya Ice Cap. By 10,900 14C yr B.P. the ice front had retreated to nearly within its modern limits. Thus, glaciers in central and southern Perú advanced and retreated in near lockstep with one another. The Younger Dryas in the Peruvian Andes was apparently marked by retreating ice fronts in spite of the cool conditions that are inferred from the ∂18O record of Sajama ice. This retreat was apparently driven by reduced precipitation, which is consistent with interpretations of other paleoclimatic indicators from the region and which may have been a nonlinear response to steadily decreasing summer insolation.

Late Quaternary glaciation and equilibrium-line altitudes of the Mayan Ice Cap, Guatemala, Central America

2010 ◽  
Vol 74 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Alex J. Roy ◽  
Matthew S. Lachniet
Keyword(s):  
Late Quaternary ◽  
Global Climate ◽  
Equilibrium Line ◽  
Lapse Rate ◽  
Ratio Method ◽  
Boreal Winter ◽  
Global Climate Changes ◽  
Freezing Level ◽  
Ice Cap ◽  
Quaternary Glaciation

AbstractThe Sierra los Cuchumatanes (3837 m), Guatemala, supported a plateau ice cap and valley glaciers around Montaña San Juan (3784 m) that totaled ∼ 43 km2 in area during the last local glacial maximum. Former ice limits are defined by sharp-crested lateral and terminal moraines that extend to elevations of ∼ 3450 m along the ice cap margin, and to ca. 3000–3300 m for the valley glaciers. Equilibrium-line altitudes (ELAs) estimated using the area–altitude balance ratio method for the maximum late Quaternary glaciation reached as low as 3470 m for the valley glaciers and 3670 m for the Mayan Ice Cap. Relative to the modern altitude of the 0°C isotherm of ∼ 4840 m, we determined ELA depressions of 1110–1436 m. If interpreted in terms of a depression of the freezing level during maximal glaciation along the modern lapse rate of − 5.3°C km–1, this ΔELA indicates tropical highland cooling of ∼ 5.9 to 7.6 ± 1.2°C. Our data support greater glacial highland cooling than at sea level, implying a high tropical sensitivity to global climate changes. The large magnitude of ELA depression in Guatemala may have been partially forced by enhanced wetness associated with southward excursions of the boreal winter polar air mass.

Rates of Deglaciation during the Last Glaciation and Holocene in the Cordillera Vilcanota-Quelccaya Ice Cap Region, Southeastern Perú

2002 ◽  
Vol 57 (3) ◽  
pp. 287-298 ◽  
Author(s):  
Bryan G. Mark ◽  
Geoffrey O. Seltzer ◽  
Donald T. Rodbell ◽  
Adam Y. Goodman
Keyword(s):  
20Th Century ◽  
Little Ice Age ◽  
Ice Age ◽  
Equilibrium Line Altitude ◽  
The West ◽  
Late 20Th Century ◽  
Ice Cap ◽  
Last Glaciation ◽  
Quelccaya Ice Cap ◽  
Over Time

AbstractMoraine chronology is combined with digital topography to model deglacial rates of paleoglacier volumes in both the Huancané Valley on the west side of the Quelccaya Ice Cap and the Upismayo Valley on the northwest side of the Cordillera Vilcanota. The fastest rates of deglaciation (39×10−5 to 114×10−5 km3 yr−1 and 112×10−5 to 247×10−5 km3 yr−1 for each valley, respectively) were calculated for the most recent paleoglaciers, corresponding to the last few centuries. These results are consistent with observations in the Venezuelan Andes showing high rates of deglaciation since the Little Ice Age. These rates also fall within the range of 20th century rates of deglaciation measured on the Quelccaya Ice Cap (29×10−5 to 220×10−5 km3 yr−1, Brecher and Thompson, 1993; Thompson, 2000). These results imply that rates of deglaciation may fluctuate significantly over time and that high rates of deglaciation may not be exclusive to the late 20th century. Equilibrium line altitude (ELA) depressions for the ice volumes of the last glaciation modeled here were computed as 230 m for the Quelccaya Ice Cap and 170 m for the Cordillera Vilcanota. Maximum ELA depressions are lower than previously published: <500 m for the Cordillera Vilcanota and <400 m for the Quelccaya Ice Cap. These lower values could imply a topographic control over paleoglacier extent.

scholarly journals Glacial areas, lake areas, and snowlines from 1975 to 2012: status of the Cordillera Vilcanota, including the Quelccaya Ice Cap, northern central Andes, Peru

2013 ◽  
Vol 7 (1) ◽  
pp. 573-634 ◽  
Author(s):  
M. N. Hanshaw ◽  
B. Bookhagen
Keyword(s):  
Confidence Interval ◽  
Spectral Unmixing ◽  
Second Step ◽  
Limited Attention ◽  
Lake Area ◽  
Tropical Andes ◽  
The Past ◽  
Ice Cap ◽  
Downstream Communities ◽  
Quelccaya Ice Cap

Abstract. Glaciers in the tropical Andes of southern Peru have received limited attention compared to glaciers in other regions (both near and far), yet remain of vital importance to agriculture, fresh water, and hydropower supplies of downstream communities. Little is known about recent glacial-area changes and how the glaciers in this region respond to climate changes, and, ultimately, how these changes will affect lake and water supplies. To remedy this, we have used 144 multi-spectral satellite images spanning almost four decades, from 1975–2012, to obtain glacial and lake-area outlines for the understudied Cordillera Vilcanota region, including the Quelccaya Ice Cap. In a second step, we have estimated the snowline altitude of the Quelccaya Ice Cap using spectral unmixing methods. We have made the following four key observations: first, since 1988 glacial areas throughout the Cordillera Vilcanota have been declining at a rate of 5.46 ± 1.70 km2 yr−1 (22-yr average, 1988–2010, with 95% confidence interval). The Quelccaya Ica Cap, specifically, has been declining at a rate of 0.67 ± 0.18 km2 yr−1 since 1980 (31-yr average, 1980–2011, also with 95% confidence interval); Second, decline rates for individual glacierized regions have been accelerating during the past decade (2000–2011) as compared to the preceding decade (1990–2000); Third, the snowline of the Quelccaya Ice Cap is retreating to higher elevations as glacial areas decrease, by a total of almost 300 m between its lowest recorded elevation in 1989 and its highest in 1998; and fourth, as glacial regions have decreased, 61% of lakes connected to glacial watersheds have shown a roughly synchronous increase in lake area, while 84% of lakes not connected to glacial watersheds have remained stable or have declined in area. Our new and detailed data on glacial and lake areas over 37 yr provide an important spatiotemporal assessment of climate variability in this area. These data can be integrated into further studies to analyze inter-annual glacial and lake-area changes and assess hydrologic dependence and consequences for downstream populations.

The Little Ice Age as Recorded in the Stratigraphy of the Tropical Quelccaya Ice Cap

Science ◽  
1986 ◽  
Vol 234 (4774) ◽  
pp. 361-364 ◽  
Author(s):  
L. G. THOMPSON ◽  
E. MOSLEY-THOMPSON ◽  
W. DANSGAARD, ◽  
P. M. GROOTES
Keyword(s):  
Little Ice Age ◽  
Ice Age ◽  
Ice Cap ◽  
Quelccaya Ice Cap

Ice Age Earth: Late Quaternary Geology and Climate

1994 ◽  
Vol 160 (2) ◽  
pp. 212
Author(s):  
Neil Roberts ◽  
Alastair G. Dawson
Keyword(s):  
Late Quaternary ◽  
Quaternary Geology ◽  
Ice Age

Ice-Core Pollen Record of Climatic Changes in the Central Andes during the last 400 yr

2005 ◽  
Vol 64 (2) ◽  
pp. 272-278 ◽  
Author(s):  
Kam-biu Liu ◽  
Carl A. Reese ◽  
Lonnie G. Thompson
Keyword(s):  
Little Ice Age ◽  
Ice Core ◽  
Climatic Changes ◽  
Ice Age ◽  
Striking Similarity ◽  
Pollen Record ◽  
Dry Period ◽  
Proxy Records ◽  
Ice Cap ◽  
Ice Accumulation

AbstractThis paper presents a high-resolution ice-core pollen record from the Sajama Ice Cap, Bolivia, that spans the last 400 yr. The pollen record corroborates the oxygen isotopic and ice accumulation records from the Quelccaya Ice Cap and supports the scenario that the Little Ice Age (LIA) consisted of two distinct phases�"a wet period from AD 1500 to 1700, and a dry period from AD 1700 to 1880. During the dry period xerophytic shrubs expanded to replace puna grasses on the Altiplano, as suggested by a dramatic drop in the Poaceae/Asteraceae (P/A) pollen ratio. The environment around Sajama was probably similar to the desert-like shrublands of the Southern Bolivian Highlands and western Andean slopes today. The striking similarity between the Sajama and Quelccaya proxy records suggests that climatic changes during the Little Ice Age occurred synchronously across the Altiplano.

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