Structural, tectonic and glaciological controls on the evolution of fjord landscapes

Glasser, Neil F.; Ghiglione, Matías C.

doi:10.1016/j.geomorph.2008.10.007

Cited by 69 publications

(40 citation statements)

References 79 publications

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“…Holtedahl 1967;Syvitski et al 1987;Barnes et al 2016;. They have developed as glacier-ice eroded pre-glacial river systems over successive Quaternary full-glacial periods, and many also have a substantial structural -geological influence (Lind & Andrews 1985;Glasser & Ghiglione 2009). The rate of development of fjords by subglacial erosion has been modelled by Harbor (1992).…”

Section: Subglacial Landformsmentioning

confidence: 99%

The variety and distribution of submarine glacial landforms and implications for ice-sheet reconstruction

Dowdeswell

Canals

Jakobsson

et al. 2016

Memoirs

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Glacimarine processes affect about 20% of the global ocean today, and this area expanded considerably under cyclical full-glacial conditions during the Quaternary (Fig. 1) . Many of the submarine landforms produced at the base and margin of past ice sheets remain well preserved on the seafloor in fjords and on high-latitude continental shelves after the retreat of the ice that produced them. These glacial landforms, protected from subaerial erosion and beneath wave-base and tidal currents in water that is often hundreds of metres deep, are gradually buried by both hemipelagic and glacimarine sedimentation; they may be preserved over long periods in the geological record if palaeocontinental shelves are not reworked by subsequent glacier advances or bottom currents ). This means that, first, submarine glacial landforms can be observed at or close to the modern seafloor after retreat of the last great ice sheets from their most recent Quaternary maximum about 18-20 000 years ago using swath-bathymetric mapping systems and, secondly, buried glacial landforms may also be identified and examined within glacial-sedimentary sequences from Quaternary and earlier ice ages using seismic-reflection methods.The development of multibeam echo sounding over the past two decades, coupled with high-accuracy GPS positioning, has allowed morphological mapping of the seafloor at an unprecedented level of detail. In this paper, the variety of submarine glacial landforms observed in modern, Quaternary and more ancient sediments is described. Landforms produced subglacially, those formed at and beyond marine ice-sheet margins, together with the slope processes and bottom currents likely to result in their reworking, are considered along with the sediment volumes of these landforms and the time they take to develop. This is followed by discussion of the significance of submarine glacial landforms and landform-assemblages for reconstruction of the form and flow of past ice sheets, including the former extent and flow direction of ice sheets, whether they are flowing fast as ice streams or slowly in inter-ice stream areas, the nature and rate of ice-sheet deglaciation, conditions at past ice-sheet beds, and inferences on the characteristics of the basal hydrological system and past climatic conditions.

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Section: Subglacial Landformsmentioning

confidence: 99%

The variety and distribution of submarine glacial landforms and implications for ice-sheet reconstruction

Dowdeswell

Canals

Jakobsson

et al. 2016

Memoirs

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“…To the west of the Andes, the landscape is dominated by an extended fjord and island system. The ice flow during successive glaciations exploited pre-existing structural faults, and over-deepened and widened the fjords and valleys through selective erosion (Glasser and Ghiglione, 2009). …”

Section: Regional Settingmentioning

confidence: 99%

The Last Glacial Maximum and deglaciation in central Patagonia, 44°S–49°S

Mendelová

Hein

McCulloch

et al. 2017

CIG

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“…1). The presence of broad and open topography is commonly associated with bedrock erodibility (e.g., Augustinus, 1995;Glasser and Ghiglione, 2009;Krabbendam and Glasser, 2011). In contrast, the nearby vertical rock walls-including Cathedral Peak, Matthes Crest, and Lembert Dome-suggest bedrock durability.…”

Section: Introductionmentioning

confidence: 99%

Preexisting fractures and the formation of an iconic American landscape: Tuolumne Meadows, Yosemite National Park, USA

Becker¹,

Tikoff²,

Riley³

et al. 2014

GSAT

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Tuolumne Meadows, in Yosemite National Park (USA), is a large sub-alpine meadow in the Sierra Nevada Mountains. Immediately adjacent to Tuolumne Meadows-and underlain by the same bedrock lithology (Cathedral Peak Granodiorite)-are vertical rock faces that provide exceptional opportunities to climbers. While the presence of a broad meadow suggests bedrock erodibility, the vertical rock walls indicate bedrock durability. We propose that the Tuolumne Meadows's landscape is the result of variable glacial erosion due to the presence or absence of preexisting bedrock fractures. The meadows and valleys formed because of concentrated tabular fracture clusters-a distinctive and locally pervasive type of fracturing-that were particularly susceptible to glacial erosion. In contrast, the vertical rock walls consist of sparsely fractured bedrock that was originally bounded by zones of pervasive tabular fracture clusters. Glacial erosion preferentially removed the highly fractured rock, forming prominent ridges in the upland surrounding Tuolumne Meadows. The orientation and spacing of the tabular fracture clusters, relative to ice flow, has exerted a fundamental control on the geomorphology of the area. The erosional variability exhibited by a single lithology indicates that the degree of fracturing can be more important than the host lithology in controlling landscape evolution.

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Structural, tectonic and glaciological controls on the evolution of fjord landscapes

Cited by 69 publications

References 79 publications

The variety and distribution of submarine glacial landforms and implications for ice-sheet reconstruction

The variety and distribution of submarine glacial landforms and implications for ice-sheet reconstruction

The Last Glacial Maximum and deglaciation in central Patagonia, 44°S–49°S

Preexisting fractures and the formation of an iconic American landscape: Tuolumne Meadows, Yosemite National Park, USA

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