Late-Holocene glacier variations on El Altar, Ecuador, have been reconstructed from proglacial lacustrine sediments. Variations in bulk density and organic content in sediment cores from Laguna Verde, are interpreted as representing a record of the Neoglacial activity of the Obsipo Glacier. Two sedimentological units of laminated silt and clay represent two late-Holocene episodes of glacier expansion, which probably occurred during the last millennium and tentatively suggest a double 'Little Ice Age' signal. Reconstructed equilibrium-line altitudes on the Obispo Glacier seem to reflect changes in both precipitation and temperature, and the glacial fluctuations documented on El Altar are consistent with other evidence of environmental change from northern South America.
Axelsson, V.1979: Sjöars sediment studeras med röntgenteknik. Ymer1979, 133-44.
2.
— 1983: The use of X-ray radiographic methods in studing sedimentary properties and rates of sediment accumulation. Hydrobiologica103, 65-69.
3.
Blystad, P. and Selsing, L.1989: Some erroneous radiocarbon dates of lacustrine sediments . Norsk Geologisk Tidskrift99, 201-208.
4.
Bradley, R.S. and Jones, P.D.1992: Climate since AD 1500. London : Routledge.
5.
Bradley, R.S. and Jones, P.D.1993: 'Little Ice Age' summer temperature variations: their nature and relevance to recent global warming trends. The Holocene3-4, 367-76.
6.
Church, M. and Gilbert, R.1975: Proglacial fluvial and lacustrine environments . In Jopling, A. and McDonald, B., editors, Glaciofluvial and glaciolacustrine sedimentation, special publication 23. Tulsa, Society of Economic Paleontologists and Mineralogists, 22-100.
7.
Church, M. and Ryder, J.M.1972: Paraglacial sedimentation: a consideration of fluvial processes conditioned by glaciation. Geological Society of America Bulletin83, 3059-3072.
8.
Clapperton, C.M.1986: Glacial geomorphology, Quaternary glacial sequence and palaeoclimatic inferences in the Ecuadorian Andes. In Gardiner, V., editor, International geomorphology 1986 Part II, London: John Wiley , 843-70.
9.
— 1990: Glacial and volcanic geomorphology of the Chimborazo-Carihuairazo massif, Ecuadorian Andes. Transactions of the Royal Society of Edinburgh: Earth Sciences81, 91-116.
10.
Clapperton, C.M. and Sugden, D.E.1988: Holocene glacier fluctuations in South America and Antarctica . Quaternary Science Reviews7,185-98.
11.
Colinvaux, P.A. and Liu, K.1987: The late-Quaternary climate of the western Amazon Basin . In Berger, W.H. and Labeyrie, L.D., editors, Abrupt climatic change . Dordrecht: D. Reidel, 113-22.
12.
Colinvaux, P.A., Miller, M.C., Liu, K., Steinitz-Kannan, M. and Frost, I.1985: Discovery of permanent Amazon lakes and hydraulic disturbance in the upper Amazon Basin. Nature313, 42-45.
13.
Folk, F.L.1980: Petrology of sedimentary rocks. Austin : Hemphillpublishing company .
14.
Graf, K.1981: Zum Höhenverlauf der Subnivalstufe in den tropischen Anden, insbesondere Bolivien und Ecuador. Zeitschrift für Geomorphologie37, 1-24.
15.
Harbor, J. and Warburton, J.1992: Glaciation and denudation rates. Nature356, 751.
16.
Hastenrath, S.1981: The glaciation of the Ecuadorian Ande. Rotterdam: A.A. Balkema.
17.
Instituto Geográfico Militar, Quito, Ecuador 1978: LARJET:R-33, 31 May 1978, 6848-50, Scale: ca. 1:60000.
18.
Instituto Geográfico Militar, Quito, Ecuador 1984: N IV-D3c (Cerros Negros), Ñ IV-F1a (Laguna Pintada), scale: 1:25000.
19.
Karlén, W.1976: Lacustrine sediments and tree-limit variations as indicators of Holocene climatic fluctuations in Lappland, northern Sweden . Geografiska Annaler58A, 1-34.
— 1985: Glacier and climate fluctuations on Mount Kenya, East Africa. Zeitschrift für Gletscherkunde und Glazialgeologie21, 195-201.
22.
Karlén, W. and Matthews, J.A.1992: Reconstructing Holocene glacier variations from glacial lakes sediments: studies from Nordvestlandet and Jostedalsbreen-Jotunheimen, southern Norway. Geografiska Annaler74A, 327-48.
23.
Karlén, W. and Rosqvist, G.1988: Glacier fluctuations recorded in lacustrine sediments on Mount Kenya. National Geographic Research4(2), 219-32.
24.
Leonard, E.M.1986a: Use of lacustrine sedimentary sequences as indicators of Holocene glacial history, Banff National Park, Alberta, Canada. Quaternary Research26, 218-31.
25.
— 1986b: Varve studies at Hector Lake, Alberta, Canada, and the relationship between glacial activity and sedimentation. Quaternary Research25, 199-214.
26.
Mierdering, T.C.1982: Late Pleistocene glacial equilibrium-line in the Colorado Front Range: A comparison of methods. Quaternary Research18, 289-310.
27.
Olsson, I.U.1979: A warning against radiocarbon dating of samples containing little carbon. Boreas8, 203-207.
28.
Rodbell, D.T.1992: Lichenometric and radiocarbon dating of Holocene glaciation, Cordillera Blanca, Peru. The Holocene2, 19-29.
29.
Rosqvist, G.1990: Quaternary glaciations in Africa. Quaternary Science Reviews9, 281-97.
30.
— 1992a: Glacial and climatic fluctuations in South Georgia . In Melander, O. and Lönnroth-Carlsson, M., editors, Swedish Antarctic research programme 1991/92. A cruise report. Stockholm : Swedish Polar Research Secretariat, 104-109.
31.
— 1992b: Late Quaternary equatorial glacier fluctuations . Unpublished PhD thesis, Stockholm University.
32.
Rosqvist, G. and østrem, G.1989: The sensitivity of a small ice cap to climatic fluctuations . Geografiska Annaler71A, 99-103.
33.
Röthlisberger, F.1987: 10000 Jahre Gletschergeschichte der Erde. Arau: Verlag Sauerlander.
34.
Roux, M., Servant-Vildary, S. and Mello e Sousa, S.1987: Diatomées et milieux aquatiques de Bolivie. Application des méthodes statistiques à l'évaluation des paléotempératures et des paléosalinités. Géodynamique2, 116-19.
35.
Rull, V., Salgado-Labouriau, M.L., Schubert, C. and Valastro, S., Jr. 1987: Late Holocene temperature depression in the Venezuelan Andes: palynological evidence. Palaeogeography, Palaeoclimatology, Palaeoecology60, 109-21.
36.
Rull, V. and Schubert, C.1989: The Little Ice Age in the tropical Venezuelan Andes . Acta Cientifica Venezolana40, 71-73.
37.
Sauer, W.1971: Geologie von Ecuador. Berlin : Gebrüder Borntræger.
38.
Schubert, C. and Clapperton, C.M.1990: Quaternary glaciations in the Northern Andes (Venezuela, Colombia, Ecuador). Quaternary Science Reviews9, 123-35.
39.
Seltzer, G.O.1990: Glacial history and paleoclimate of the Peruvian-Bolivian Andes. Quaternary Science Reviews9, 137-52.
40.
Steinitz-Kannan, M., Colinvaux, P.A. and Kannan, R.1983: Limnological studies in Ecuador: 1. A survey of chemical and physical properties of Ecuadorian lakes. Archive für Hydrobiologie65, 61-105.
41.
Thompson, L.G.1992: Ice core evidence from Peru and China. In Bradley, R.S. and Jones, P.D., editors, Climate since AD1500. London: Routledge, 517-48.
42.
Thompson, L.G., Mosley-Thompson, E., Bolzen, J.F. and Koci, B.R.1985: A 1500-years record of tropical precipitation in the ice cores from the Quelccaya Ice Cap, Peru. Science229, 971-73.
43.
Thompson, L.G., Mosley-Thompson, E., Dansgaard, W. and Grootes, P.M.1986: The Little Ice Age recorded in the stratigraphy of the Quelccaya ice cap. Science234, 361-64.
