Quaternary glaciations of the southern Andes

Rabassa, Jorge; Clapperton, Chalmers M.

doi:10.1016/0277-3791(90)90016-4

Cited by 310 publications

(234 citation statements)

References 28 publications

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“…In the Quaternary, glaciers have substantially modified the landscape (Sugden and John, 1976), especially in temperate middle latitude areas such as Patagonia where basal conditions were warm-based. Here we argue for a connection between the phenomena of glacial erosion and the pattern of the extent of ice over time in southern South America, which builds upon prior discussions of the topic (e.g., Rabassa and Clapperton, 1990;Singer et al, 2004a). We focus on the records of glacial landforms in the Andes and possible changes in paleoglaciology, in comparison to other papers on the subject of glaciations and landscape development (e.g., Harbor, 1992;Small and Anderson, 1998;Whipple et al, 1999;MacGregor et al, 2000;Montgomery et al, 2001;Tomkins and Braun, 2002;Thomson, 2002).…”

Section: Introductionmentioning

confidence: 67%

“…We focus on southern South America to observe long-term changes in the extent of ice because (in places) it contains one of the best-dated, longest glacial moraine (i.e., frontal position) records on Earth, ~ 1 Myr (Mercer, 1983;Rabassa and Clapperton, 1990;Clapperton, 1993). From 40ºS to 55ºS latitude, moraines and till sheets clearly show that glacial expansions have been less extensive in general since the GPG, at 1.1 Ma (Caldenius, 1932, Rabassa andClapperton, 1990;Mercer, 1983;Meglioli, 1992;Singer et al, 2004a;Coronato et al, 2004a;Rabassa et al, 2005).…”

Section: Decreasing Ice Extent In Patagoniamentioning

confidence: 99%

“…1, 2). The trend exists for > 1500 km along the southern Andes, it is not particular to any individual valley, and the successions contain several moraines of different ages (Rabassa and Clapperton, 1990;Mercer, 1983;Singer et al, 2004a). Gibbons et al (1984) showed that the expected preservation is only 2-3 moraines for a random succession of advances, given that subsequent glacial advances remove previously deposited moraines.…”

Section: Introductionmentioning

confidence: 97%

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Can glacial erosion limit the extent of glaciation?

et al. 2009

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In southern South America, the maximum areal extent of ice during the Quaternary Period, the Greatest Patagonian Glaciation (GPG, Mercer, 1983), occurred at 1.1 Ma and subsequent glaciations were overall less extensive. The GPG preceded global minimum temperatures and maximal volume of ice, which occurred in the last ~ 800 kyr, as recorded in the marine δ 18 O record. Significant modification of the drainage morphology of the southern Andes from a non-glaciated to glaciated landscape occurred throughout the Quaternary Period. We infer a non-climatic relationship between glacial modification of the mountains and decreasing the extent of ice and we discuss processes of landscape development that could have caused the trend. Specifically, these include modification of valleys, such as development from a V-to a Ushape, and lowering of mass-accumulation areas. Such changes would strongly affect glacial dynamics, the mass balance profile and mass-flux during succeeding glaciations, especially for low-gradient outlet glaciers occupying low areas. Other areas around Earth (at least where ice has been warm-based) also may exhibit a non-random trend of decreasing the extent of ice with time, ultimately because of glacial erosion in the Quaternary Period.

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Section: Introductionmentioning

confidence: 67%

Section: Decreasing Ice Extent In Patagoniamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

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Can glacial erosion limit the extent of glaciation?

et al. 2009

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“…Black arrows are indicating the northward gliding Chiloé block. The dashed line marks the maximum extent of the Patagonian Ice Sheet during the Last Glacial (after Rabassa and Clapperton, 1990). …”

Section: Regional Tectonic and Geologic Settingmentioning

confidence: 99%

Forearc uplift rates deduced from sediment cores of two coastal lakes in south-central Chile

et al. 2010

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The present paper introduces a new approach for deriving information about local forearc tectonics and related uplift rates based on the study of lake sediments. We investigated two coastal lakes at the south-central Chile margin, lakes Lanalhue and Lleu Lleu, located south of the Arauco Peninsula (38°S). Both lakes developed within the valleys of ancient rivers that once drained to the Pacific Ocean, being subsequently dammed by rising sills in the late Pleistocene/early Holocene. Seismic profiling and sedimentological analyses of cores from both lakes revealed similar successions consisting of marine to brackish sediments covered by lacustrine deposits. Radiocarbon dating indicates that the marine-lacustrine transition occurred at 8 ka and 8.15 ka, respectively. The correlation of this transition with global sea-level curves allowed the calculation of local uplift rates for the Holocene. Uplift rates for the lake basins amount to 0.42 ± 0.71 and 0.49 ± 0.44 mm/a, respectively, which are consistent with rates determined from a late Pleistocene marine terrace in the area. However, conspicuously higher, though likely transient, vertical movements at 8.83 ± 2.7 mm/a and 11.36 ±1.77 mm/a, respectively, were calculated for the sills that block both lakes nowadays. These barriers are interpreted to be the surface expression of a blind reverse fault associated to the Morguilla fault system, a seismically-active structure that controls uplift and folding along the adjacent Arauco Peninsula.

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“…Starting from Pliocene times, and during most of the Quaternary, both glaciation and volcanism have shaped the landscape of the Patagonian Andes, which is presently characterized by low ice-capped topographies with a steep relief (Mercer and Sutter, 1982;Rabassa and Clapperton, 1990;Heusser, 1990;Montgomery et al, 2001;Rosenau et al, 2006).…”

Section: Geological Settingmentioning

confidence: 99%

Cooling histories and deformation of plutonic rocks along the Liquiñe-Ofqui Fault Zone, Southern Chile (41°-42°15'S)

Adriasola

Stöckhert

2008

Rev. geol. Chile

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ABSTRACT. Structural and microstructural observations combined with apatite and zircon fi ssion-track thermochronology within two sectors of the Main Andean Range in the Los Lagos Region of Chile reveal an episodic history of intrusion and deformation in the North Patagonian Batholith (NPB). A dextral displacement of ~30 km along the Liquiñe-Ofqui fault zone (LOFZ) is inferred from the correlation of corresponding Cretaceous intrusions of the NPB across the fault zone at Reloncaví. Relative uplift of the western block in the late Miocene is indicated by apatite and zircon fi ssiontrack cooling histories. Microstructures in samples from Miocene and Cretaceous plutons along the fault zone generally indicate deformation at temperatures below ~300°C, with the exception of some samples from Cretaceous intrusions showing deformation at higher temperatures. In the Hornopirén area, signifi cant relative uplift of the eastern block is indicated by 1. the different styles of deformation observed across the fault zone, 2. kinematic analysis of a shear zone in tonalite and 3. geobarometry of contact metamorphic mineral assemblages. For the plutonic rocks in the Hornopirén area, extremely rapid cooling is indicated by thermochronometry, suggesting the activity of hydrothermal systems or thermal effects of late shallow intrusions.

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Quaternary glaciations of the southern Andes

Cited by 310 publications

References 28 publications

Can glacial erosion limit the extent of glaciation?

Can glacial erosion limit the extent of glaciation?

Forearc uplift rates deduced from sediment cores of two coastal lakes in south-central Chile

Cooling histories and deformation of plutonic rocks along the Liquiñe-Ofqui Fault Zone, Southern Chile (41°-42°15'S)

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