Surface textural analysis of quartz sand grains from ODP Site 918 off the southeast coast of Greenland suggests glaciation of southern Greenland at 11 Ma

Helland, P. E.; Holmes, Mary Anne

doi:10.1016/s0031-0182(97)00025-4

Cited by 116 publications

(67 citation statements)

References 19 publications

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“…LEO 430). Grain morphology and surface microtextures have been studied and interpreted to understand the transport mechanism and depositional environment of the sediments following the method adopted from Krinsley and Doornkamp (1973), Mahaney (1995), Helland and Holmes (1997), Strand et al (2003) and Vos et al (2014). …”

Section: Methodsmentioning

confidence: 99%

“…These grains can be derived from various provenances, such as, mechanically or chemically derived quartz grains, wind-driven aeolian quartz and biogenic silica consisting mostly of diatoms (Stanley and DeDeckker 2002). Quartz grain microtextures and morphology, like grain shape, fracture patterns, step patterns etc., depend primarily on the conditions of transportation and deposition, and hence provide records of the past environment and climate (Whalley and Krinsley 1974;Mahaney et al 1996;Helland and Holmes 1997;Hart 2006;Mathur et al 2009). The studies of such quartz grains under Scanning Electron Microscope (SEM) can reveal the details of different geological processes that the grains have undergone during transportation and deposition (Mahaney 1995;Strand et al 2003).…”

Section: Introductionmentioning

confidence: 99%

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Paleoenvironments of a proglacial lake in Schirmacher Oasis, East Antarctica: Insights from quartz grain microtextures

Mazumder¹,

Govil²,

Kar³

et al. 2017

Polish Polar Research

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This paper provides an overview of the results of research on changes in ground temperature down to 50 cm depth, on the Kaffiøyra Plain, Spitsbergen in the summer seasons. To achieve this, measurement data were analysed from three different ecotopes (CALM Site P2A, P2B and P2C) -a beach, a moraine and tundra -collected during 22 polar expeditions between 1975 and 2014. To ensure comparability, data sets for the common period from 21 July to 31 August (referred to as the "summer season" further in the text) were analysed. The greatest influence on temperature across the inves− tigated ground layers comes from air temperature (correlation coefficients ranging from 0.61 to 0.84). For the purpose of the analysis of the changes in ground temperature in the years 1975-2014, missing data for certain summer seasons were reconstructed on the ba− sis of similar data from a meteorological station at Ny−Ålesund. The ground temperature at the Beach site demonstrated a statistically−significant growing trend: at depths from 1 to 10 cm the temperature increased by 0.27-0.28°C per decade, and from 20 to 50 cm by as much as 0.30°C per decade. On the Kaffiøyra Plain, the North Atlantic Oscillation (NAO) has a greater influence on the ground and air temperature than the Arctic Oscilla− tion (AO).

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Paleoenvironments of a proglacial lake in Schirmacher Oasis, East Antarctica: Insights from quartz grain microtextures

Mazumder¹,

Govil²,

Kar³

et al. 2017

Polish Polar Research

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“…Furthermore, the record of ice-rafted debris (IRD) at other high latitude sites close to Greenland (e.g. Schaeffer and Spiegler, 1986;Fronval and Jansen, 1996;Wolf-Welling et al, 1996;Helland and Holmes, 1997) suggests the establishment of small-scale glaciations on Greenland large enough to reach sea level at around this time. However, based on the stratigraphic occurrence at Site 907 it is difficult to assess the detailed paleoecological affinities of B. bergenensis sp.…”

Section: Resultsmentioning

confidence: 99%

Batiacasphaera bergenensis and Lavradosphaera elongata — New dinoflagellate cyst and acritarch species from the Miocene of the Iceland Sea (ODP Hole 907A)

Schreck

Matthießen

2014

Review of Palaeobotany and Palynology

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A detailed palynological investigation of the almost continuous middle through upper Miocene sediment sequence of ODP Hole 907A in the Iceland Sea revealed the presence of a new species of the dinoflagellate cyst genus Batiacasphaera, and a new species of the acritarch genus Lavradosphaera. Batiacasphaera bergenensis sp. nov. and Lavradosphaera elongata sp. nov. are both morphologically distinctive and have well-defined stratigraphic range tops that are independently constrained by the pristine paleomagnetic record of Hole 907A. Both species disappeared within a narrow interval across the middle to late Miocene boundary, when smallscale glaciations on Greenland were large enough to reach sea level. The distinct morphology of the proposed species and their highest occurrence in this critical interval highlights their potential for future biostratigraphic application in the Miocene of the high northern latitudes, an area important for understanding the Late Cenozoic transition into a bipolar glaciated world.

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“…The increased advection of colder waters may have triggered the coeval collapse in accumulation of Chaetoceros resting spores reflecting a diminished diatom production (Stabell and Koç, 1996). Benthic δ 18 O values on Vøring Plateau indicate substantial deep water cooling at~11 Ma (Fronval and Jansen, 1996), and increased circum-Arctic IRD fluxes between 11.0 and 9.5 Ma (Schaeffer and Spiegler, 1986;Thiébault et al, 1989;Wolf and Thiede, 1991;Fronval and Jansen, 1996;Wolf-Welling et al, 1996;Helland and Holmes, 1997;Winkler et al, 2002) prove general cooling in the high northern latitudes. The timing of IRD events broadly corresponds to a major uplift phase on Greenland (Thomson et al, 1999;Japsen et al, 2006) suggesting a pivotal role in establishing the Greenland Ice Sheet during Late Miocene times, when pCO 2 stabilized at pre-industrial values (Pagani et al, 1999).…”

Section: Glacial Inception In the Iceland Sea (~107-102 Ma)mentioning

confidence: 99%

“…Although it has been speculated that a Neogene Greenland Ice Sheet has existed since at least 18 Ma (Thiede et al, 2011), published records suggest that small scale glaciations large enough to reach sea-level might have occurred on Greenland not before the early to middle Late Miocene (Schaeffer and Spiegler, 1986;Wolf and Thiede, 1991;Fronval and Jansen, 1996;Wolf-Welling et al, 1996;Helland and Holmes, 1997;Winkler et al, 2002). In contrast, ice sheets probably developed in the northern Barents Sea and on Scandinavia already in the Middle Miocene (Fronval and Jansen, 1996;Knies and Gaina, 2008).…”

Section: Introductionmentioning

confidence: 99%

Response of marine palynomorphs to Neogene climate cooling in the Iceland Sea (ODP Hole 907A)

Schreck

Méheust

Stein

et al. 2013

Marine Micropaleontology

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The present study on ODP Leg 151 Hole 907A combines a detailed analysis of marine palynomorphs (dinoflagellate cysts, prasinophytes, and acritarchs) and a low-resolution alkenone-based sea-surface temperature (SST) record for the interval between 14.5 and 2.5 Ma, and allows to investigate the relationship between palynomorph assemblages and the paleoenvironmental evolution of the Iceland Sea. A high marine productivity is indicated in the Middle Miocene, and palynomorphs and SSTs both mirror the subsequent long-term Neogene climate deterioration. The diverse Middle Miocene palynomorph assemblages clearly diminish towards the impoverished assemblages of the Late Pliocene; parallel with a somewhat gradual decrease of SSTs being as high as 20°C at~13.5 Ma to around 8°C at~3 Ma. Superimposed, palynomorph assemblages not only reflect Middle to Late Miocene climate variability partly coinciding with the short-lived global Miocene isotope events (Mi-events), but also the initiation of a proto-thermohaline circulation across the Middle Miocene Climate Transition, which led to increased meridionality in the Nordic Seas. Last occurrences of species cluster during three events in the Late Miocene to Early Pliocene and are ascribed to the progressive strengthening and freshening of the proto-East Greenland Current towards modern conditions. A significant high latitude cooling between 6.5 and 6 Ma is depicted by the supraregional "Decahedrella event" coeval with lowest Miocene productivity and a SST decline. In the Early Pliocene, a transient warming is accompanied by surface water stratification and increased productivity that likely reflects a high latitude response to the global biogenic bloom. The succeeding crash in palynomorph accumulation, and a subsequent interval virtually barren of marine palynomorphs may be attributed to enhanced bottom water oxygenation and substantial sea ice cover, and indicates that conditions seriously affecting marine productivity in the Iceland Sea were already established well before the marked expansion of the Greenland Ice Sheet at 3.3 Ma.

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Surface textural analysis of quartz sand grains from ODP Site 918 off the southeast coast of Greenland suggests glaciation of southern Greenland at 11 Ma

Cited by 116 publications

References 19 publications

Paleoenvironments of a proglacial lake in Schirmacher Oasis, East Antarctica: Insights from quartz grain microtextures

Paleoenvironments of a proglacial lake in Schirmacher Oasis, East Antarctica: Insights from quartz grain microtextures

Batiacasphaera bergenensis and Lavradosphaera elongata — New dinoflagellate cyst and acritarch species from the Miocene of the Iceland Sea (ODP Hole 907A)

Response of marine palynomorphs to Neogene climate cooling in the Iceland Sea (ODP Hole 907A)

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