Jet-efflux deposits of a subaqueous ice-contact fan, glacial Lake Rinteln, northwestern Germany

Hornung, Jahn J.; Asprion, Ulrich; Winsemann, Jutta

doi:10.1016/j.sedgeo.2005.11.024

Cited by 57 publications

(84 citation statements)

References 46 publications

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“…Put simply, subglacial meltwater deposits are the product of a hydrological regime that is not unique to subglacial environments, with similar regimes documented from a range of other sedimentary environments including intertidal (Cheel & Middleton, 1986), fluvial (Cheel, 1990, Røe, 1987Alexander et al, 2001) and channelised turbidity currents (Ito & Saito, 2006). Upper plane bed flow regimes have also been recognised within glacial meltwater systems including subglacial (this study ;Brennand, 1994;Fisher et al, 2003), englacial (Delaney, 2001(Delaney, , 2002 proglacial (Duller et al, 2008) and subaqueous ice-contact environments (Russell & Arnott, 2003;Hornung et al, 2007;Lang & Winsemann, 2013).…”

Section: 3mentioning

confidence: 70%

Sedimentary and structural evolution of a relict subglacial to subaerial drainage system and its hydrogeological implications: an example from Anglesey, north Wales, UK

Lee

Wakefield

Phillips

et al. 2015

Quaternary Science Reviews

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Subglacial drainage systems exert a major control on basal-sliding rates and glacier dynamics. However, comparatively few studies have examined the sedimentary record of subglacial drainage. This is due to the paucity of modern analogues, the limited recognition and preservation of upper flow regime deposits within the geological record, and the difficulty of distinguishing subglacial meltwater deposits from other meltwater sediments (e.g. glacier outburst flood deposits). Within this study, the sedimentological and structural evolution of a subglacial to subaerial (ice-marginal / proglacial) drainage system is examined. Particular emphasis is placed upon the genetic development and preservation of upper flow regime bedforms and specifically recognising them within a subglacial meltwater context. Facies attributed to subglacial meltwater activity record sedimentation within a confined, but progressively enlargening, subglacial channel system produced under dune to upper flow regime conditions. Bedforms include rare large-scale sinusoidal bedding with syn-depositional deformation produced by current-induced traction and shearing within the channel margins. Subglacial sedimentation culminated with the abrupt change to a more ephemeral drainage regime indicating channel-abandonment or a seasonal drainage regime. Retreat of the ice margin, led to the establishment of subaerial drainage with phases of sheet-flow punctuated by channel incision and anastomosing channel development under diurnal, ablation-related, seasonal discharge. The presence of extensive hydrofracture networks demonstrate that proglacial groundwater-levels fluctuated markedly and this may have influenced later overriding of the site by an ice stream.

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Section: 3mentioning

confidence: 70%

Sedimentary and structural evolution of a relict subglacial to subaerial drainage system and its hydrogeological implications: an example from Anglesey, north Wales, UK

Lee

Wakefield

Phillips

et al. 2015

Quaternary Science Reviews

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“…3a). This feature records waxing flows that maintain an aggradational behaviour at the ice front (Hornung et al 2007). Interbedded chute-and-pool structures capped by antidunes ( Fig.…”

Section: Uppermost Mamuniyat Formationmentioning

confidence: 96%

Did lingering ice sheets moderate anoxia in the Early Palaeozoic of Libya?

Heron

Meinhold

Page

et al. 2013

JGS

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Abstract:The Hirnantian glaciation of West Gondwana produced a glacially sculpted topography, which is draped by organic-rich latest Ordovician and early Silurian 'hot shales'. Although these are the most important Early Palaeozoic source rock in North Africa, organic enrichment is distributed unevenly. For example, in Al Kufrah Basin, Libya, 'hot shales' are elusive, but outcrop analysis at the western basin demonstrates why this is the case. The topmost Mamuniyat Formation, of Hirnantian age, comprises glaciogenic sandstones, passing upward into mixed facies of the Tanezzuft Formation, which has a latest Ordovician-early Silurian age. The basal Tanezzuft Formation contains a shelly carbonate (cool-water deposits accumulated under oxygenating conditions) and bioturbated sandstone succession. Above, hummocky cross-bedded and graded sandstone intervals are intercalated with shale and siltstone (storm influx onto a muddy shelf). These are interrupted by several lonestone-bearing intervals (ice-rafted debris), a striated pavement (of subglacial origin), and manganese oxide crusts and concretions. The concretions and bioturbation imply oxygenation of the sea floor during transgression. These putative glacial deposits were deposited following the main phase of the Hirnantian glaciation, at the same stratigraphic level as 'hot shales' elsewhere in northern Gondwana. Lingering ice caps may have produced well-oxygenated marine waters precluding 'hot shale' deposition.

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“…2) mainly deposited from highenergy meltwater flows (Winsemann et al, 2004;Hornung et al, 2007). Well logs and several clay pits record the widespread occurrence of up to 20 m thick fine-grained lake bottom sediments ('Hauptbeckenton'), overlying older Quaternary fluvial deposits of the River Weser or bedrocks in the basin centre (c. 55 -75 m a.s.l.).…”

Section: Study Area and Previous Reseachmentioning

confidence: 99%

“…Re-examination of outcrops indicate a subaqueous origin of these ice-marginal deposits (Winsemann et al, 2003;Hornung et al, 2007). Several sediment characteristics indicative of subaqueous fan versus subaerial deposition were recorded (e.g.…”

Section: Study Area and Previous Reseachmentioning

confidence: 99%

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Lake‐Level Control on Ice‐Margin Subaqueous Fans, Glacial Lake Rinteln, Northwest Germany

Winsemann

Asprion

Meyer

2007

Glacial Sedimentary Processes and Products

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During the maximum advance of the Early Saalian Scandinavian Ice Sheet ice-dammed lakes developed within valleys of the Northwest German Mountain ranges. The blocking of the River Weser valley led to the formation of glacial Lake Rinteln where most of the sediment was deposited by meltwater. Two subaqueous fan complexes have been identified, which formed lakeward of retreating ice-lobes during an overall lake-level rise. The sediment transport on the fans has been dominated by sustained gravity-flows, mainly cohesionless debris flows or high-and low-density turbidity currents, reflecting discharge of semi-continuous meltwater flows. Intercalations of surge-type high-and lowdensity turbidites increase towards the mid-and lower-fan slopes, indicating more ice-distal and periodic deposition. Individual fan bodies commonly have a coarse-grained proximal core of steeply dipping gravel, overlain by gently to steeply dipping mid-to outer fan deposits. During glacier retreat commonly fine-grained sediments, rich in ice-rafted debris, were deposited on the ice-distal and ice-proximal slopes of the abandoned fans. Climbing-ripple cross-laminated sand may onlap coarse-grained upper fan gravel and in some cases overtop the older fan deposits. Phases of glacier still-stands are characterised by fan systems that display an upward flattening of fan clinoforms and minor vertical facies changes. The position of ice marginal fans was controlled by the combination of bedrock topography and water depth. At the eastern lake margin topographic highs served as pinning points for the retreating glacier and facilitated ice margin stabilisation. A strong lake-level fall probably triggered a major drainage event that tapped previously unconnected reservoirs of englacial and subglacial meltwater.

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Jet-efflux deposits of a subaqueous ice-contact fan, glacial Lake Rinteln, northwestern Germany

Cited by 57 publications

References 46 publications

Sedimentary and structural evolution of a relict subglacial to subaerial drainage system and its hydrogeological implications: an example from Anglesey, north Wales, UK

Sedimentary and structural evolution of a relict subglacial to subaerial drainage system and its hydrogeological implications: an example from Anglesey, north Wales, UK

Did lingering ice sheets moderate anoxia in the Early Palaeozoic of Libya?

Lake‐Level Control on Ice‐Margin Subaqueous Fans, Glacial Lake Rinteln, Northwest Germany

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