Evidence of iceberg-ploughing in a subaqueous ice-contact fan, glacial Lake Rinteln, NW Germany

Winsemann, Jutta; Asprion, Ulrich; Meyer, Thomas; SCHULTZ, HARM; Victor, Pia

doi:10.1080/03009480301819

Cited by 23 publications

(13 citation statements)

References 32 publications

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“…These deformation structures affect sediments that were formed by subaqueous density flows (F3.6), while deadice melting ice is more likely to occur within proglacial glaciofluvial deposits. Winsemann et al (2003) described an example of ice buried within subaqueous deposits where the entrapped ice was thought to be the result of the break-up of a ploughed iceberg. The buried keel fragment of the iceberg remained within the subaqueous sediments, causing normal faulting and downwarping of the surrounding strata during progressive melting.…”

Section: Discussionmentioning

confidence: 99%

“…Winsemann et al . () described an example of ice buried within subaqueous deposits where the entrapped ice was thought to be the result of the break‐up of a ploughed iceberg. The buried keel fragment of the iceberg remained within the subaqueous sediments, causing normal faulting and downwarping of the surrounding strata during progressive melting.…”

Section: Facies Descriptions Stacking Pattern and Deformation Structmentioning

confidence: 97%

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Sedimentological and deformational criteria for discriminating subglaciofluvial deposits from subaqueous ice‐contact fan deposits: A Pleistocene example (Ireland)

et al. 2014

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A pit located near Ballyhorsey, 28 km south of Dublin (eastern Ireland), displays subglacially deposited glaciofluvial sediments passing upwards into proglacial subaqueous ice‐contact fan deposits. The coexistence of these two different depositional environments at the same location will help with differentiation between two very similar and easily confused glacial lithofacies. The lowermost sediments show aggrading subglacial deposits indicating a constrained accommodation space, mainly controlled by the position of an overlying ice roof during ice‐bed decoupling. These sediments are characterized by vertically stacked tills with large lenses of tabular to channelized sorted sediments. The sorted sediments consist of fine‐grained laminated facies, cross‐laminated sand and channelized gravels, and are interpreted as subglaciofluvial sediments deposited within a subglacial de‐coupled space. The subglaciofluvial sequence is characterized by glaciotectonic deformation structures within discrete beds, triggered by fluid overpressure and shear stress during episodes of ice/bed recoupling (clastic dykes and folds). The upper deposits correspond to the deposition of successive hyperpycnal flows in a proximal proglacial lake, forming a thick sedimentary wedge erosively overlying the subglacial deposits. Gravel facies and large‐scale trough bedding sand are observed within this proximal wedge, while normally graded sand beds with developed bedforms are observed further downflow. The building of the prograding ice‐contact subaqueous fan implies an unrestricted accommodation space and is associated with deformation structures related to gravity destabilization during fan spreading (normal faults). This study facilitates the recognition of subglacial/submarginal depositional environments formed, in part, during localized ice/bed coupling episodes in the sedimentary record. The sedimentary sequence exposed in Ballyhorsey permits characterization of the temporal framework of meltwater production during deglaciation, the impact on the subglacial drainage system and the consequences on the Irish Sea Ice Stream flow mechanisms.

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Section: Discussionmentioning

confidence: 99%

Section: Facies Descriptions Stacking Pattern and Deformation Structmentioning

confidence: 97%

Sedimentological and deformational criteria for discriminating subglaciofluvial deposits from subaqueous ice‐contact fan deposits: A Pleistocene example (Ireland)

et al. 2014

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“…, 1999; Rijsdijk, 2001; Phillips et al. , 2002; Winsemann et al. , 2003), this remains relatively unexplored in the analysis of ancient glacigenic successions (e.g.…”

Section: Introductionmentioning

confidence: 99%

Deformation in the Neoproterozoic Smalfjord Formation, northern Norway: an indicator of glacial depositional conditions?

Arnaud¹

2007

Sedimentology

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Recent studies on Neoproterozoic climate change has prompted renewed interests in Neoproterozoic glacial deposits and renewed debates over the criteria used to identify the nature of glacial influence on sedimentation. Analysis of soft sediment deformation structures have provided important clues to distinguish between competing paleoenvironmental interpretations of Quaternary glacial deposits. A similar approach is presented here in the analysis of Neoproterozoic glacial deposits of the Smalfjord Formation, northern Norway. Detailed sedimentological and structural analysis at several sites in the Varangerfjorden area reveals complex soft sediment deformation at various scales in conglomerate, sandstone and diamictite.Deformation is predominantly ductile and includes anticlinal and synclinal folding, flow noses, flame structures, recumbent folding and shear structures. The deformed sediments are predominantly associated with conglomerate and sandstone, which record glaciofluvial and deltaic depositional conditions. Some deformation can be attributed to rapid deposition and slumping, whereas others appear to record shear stress associated with overriding ice. The scale, style and range of deformation together with the coarse-grained nature of the deformed sediments and facies associations suggests these were unfrozen outwash sediments that were overridden by ice and resedimented in a dynamic ice proximal setting. Whereas recent previous studies of diamictite-bearing strata of the Smalfjord Formation had revealed no clear evidence of glacial influence on deposition, deformation structures documented here suggest that glacial conditions prevailed on the basin margin during deposition of Smalfjord Formation sediments, with sedimentary facies and deformation structures typical of temperate ice proximal settings.Keywords: Neoproterozoic, Varangerfjord, ductile deformation, glaciofluvial environment, 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 proposed for these Neoproterozoic successions ranging from 'normal' glaciations similar to those experienced in the Phanerozoic (e.g. Condon et al., 2001; Allen et al., 2004) to the extreme and unprecedented 'snowball Earth' glaciations with global ice covering equatorial oceans (Hoffman et al., 1998; Hoffman and Schrag, 2002).Part of the discussion on the nature of Neoproterozoic climate change has been, and continues to be, over the controversial origin of diamictite-bearing strata and the criteria used to determine the extent and nature of glacial influence on their deposition (Harland, 1964; Crowell, 1964; Schermerhorn, 1974; Flint, 1975; Hambrey and Harland, 1978; Boulton and Deynoux, 1981; Eyles, 1993; Christie-Blick et al., 1999; Eyles and Januszczak, 2004). Whereas clast characteristics such as striations, faceting and extra-basinal composition have been used to suggest a glac...

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“…However, most published records of iceberg scours describe larger structures than this one (e.g. Eden & Eyles 2001), although scours of similar size have been identified (Winsemann et al . 2003).…”

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confidence: 99%

Chronology and styles of glaciation in an inter-fjord setting, northwestern Svalbard

Alexanderson

Landvik

Ryen

2010

Boreas

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Alexanderson, H., Landvik, J. Y. & Ryen, H. T. 2010: Chronology and styles of glaciation in an inter‐fjord setting, northwestern Svalbard. Boreas, 10.1111/j.1502‐3885.2010.00175.x. ISSN 0300‐9483. A 30‐m‐thick sedimentary succession at Leinstranda on the southwestern coast of Brøggerhalvøya, northwestern Svalbard, spans the two last glacial–interglacial cycles and reveals information on glacial dynamics, sea‐level changes and the timing of these events. We investigated the deposits using standard stratigraphical and sedimentological techniques, together with ground‐penetrating radar, and established an absolute chronology based mainly on optically stimulated luminescence dating. We identified facies associations that represent depositional settings related to advancing, overriding and retreating glaciers, marine and littoral conditions and periglacial surfaces. The environmental changes show an approximate cyclicity and reflect glaciations followed by high sea levels and later regression. The luminescence chronology places sea‐level highstands at 185 ± 8 ka, 129 ± 10 ka, 99 ± 8 ka and 36 ± 3 ka. These ages constrain the timing of recorded glaciations at Leinstranda to prior to c. 190 ka, between c. 170 and c. 140 ka (Late Saalian) and between c. 120 ka and c. 110 ka (Early Weichselian). The glaciations include phases with glaciers from three different source areas. There is no positive evidence for either Middle or Late Weichselian glaciations covering the site, but there are hiatuses at those stratigraphic levels. A high bedrock ridge separates Leinstranda from the palaeo‐ice stream in Kongsfjorden, and the deposits at Leinstranda reflect ice‐dynamic conditions related to ice‐sheet evolution in an inter‐fjord area. The environmental information and the absolute chronology derived from our data allow for an improved correlation with the marine record, and for inferences to be made about the interaction between land, ocean and ice during the last glacial–interglacial cycles.

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Evidence of iceberg-ploughing in a subaqueous ice-contact fan, glacial Lake Rinteln, NW Germany

Cited by 23 publications

References 32 publications

Sedimentological and deformational criteria for discriminating subglaciofluvial deposits from subaqueous ice‐contact fan deposits: A Pleistocene example (Ireland)

Sedimentological and deformational criteria for discriminating subglaciofluvial deposits from subaqueous ice‐contact fan deposits: A Pleistocene example (Ireland)

Deformation in the Neoproterozoic Smalfjord Formation, northern Norway: an indicator of glacial depositional conditions?

Chronology and styles of glaciation in an inter-fjord setting, northwestern Svalbard

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