Environmental Interpretation of Sand Grain Surface Textures by Electron Microscopy

Krinsley, David H.; Donahue, Jack

doi:10.1130/0016-7606(1968)79[743:eiosgs]2.0.co;2

Cited by 215 publications

(106 citation statements)

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“…15) and is composed of predominately fine to coarse sand-sized material consisting of quartz, altered feldspars, and minor amounts of mica and heavy minerals (Breza and Wise, this volume). A large portion of the quartz grains are highly angular with fresh conchoidal fractures and other surface textures that, according to Krinsley and Donahue (1968), are characteristic of glacially derived material (Figs. 16A-16C).…”

Section: An Early Oligocene Antarctic Ice Sheet?mentioning

confidence: 99%

Paleogene Glacial History of Antarctica in Light of Leg 120 Drilling Results

Wise¹,

Breza²,

Harwood³

et al. 1992

Proceedings of the Ocean Drilling Program

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The Paleogene glacial history of Antarctica has been inferred largely from indirect evidence of glaciation gathered from the oceans beyond that remote, ice-shrouded, and inhospitable continent. This evidence includes the "proxy" stable isotopic record from the world's oceans; the occurrence of ice-rafted debris (IRD) in the Southern Ocean; inflections in sea-level curves; the presence of hiatuses in the deep-sea record; and changes in clay mineral assemblages, in the diversities of microfossil assemblages, and in the steepness of latitudinal biotic gradients. Ocean Drilling Program Leg 120 has added an important dimension to this growing body of evidence through the discovery of lowest Oligocene IRD at Site 748 on the Southern Kerguelen Plateau at a record distance north of the Antarctic continent (58°S latitude) and within a pelagic biosiliceous-carbonate ooze sequence that has yielded a complementary oxygen isotope record of the cryospheric event. We deduce that an ice sheet reached sea level during the earliest Oligocene (35.8-36.0 Ma) and that the effect was immediate and profound. In addition to the IRD, this event was manifested at Site 748 by a dramatic cooling of the surface waters surrounding the continent as indicated by a sharp increase in the percentage of cold-water calcareous nannoplankton, an increase in planktonic foraminiferal δ 18 θ values, and an increase in the percentage of biosiliceous material in the sediment. The temperature of the bottom waters over the plateau also decreased, and the volume of ice on the continent increased.We have reviewed the accumulated evidence from this and other investigations of the past two decades on and around Antarctica, and have concluded that ice sheets were present on the continent during the Oligocene, including the earliest Oligocene. Not necessarily permanent features, they probably went through many advances and contractions and may have disappeared completely at times. The rapid ice advance during the earliest Oligocene reached sea level at several widely scattered localities around the continent, but only for a brief period of time at some of these localities. Differences of opinion among investigators concern primarily the size and persistence of the Oligocene ice sheet(s).Tantalizing evidence of undated till deposits subjacent to well-dated Oligocene glaciomarine sequences along the Antarctic margin and possible occurrences of IRD beyond suggest the presence of glaciers during the late Eocene and possibly even during the early-middle Eocene. Included among the studies in this Scientific Results volume are new age calibrations from Eltanin piston cores taken at relatively low latitudes (38° to 58°S) in the southeast Pacific from which Eocene IRD has been reported. There is little agreement, however, among investigators as to whether an ice sheet was present at any time during the Eocene, particularly during early-middle Eocene times.

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Section: An Early Oligocene Antarctic Ice Sheet?mentioning

confidence: 99%

Paleogene Glacial History of Antarctica in Light of Leg 120 Drilling Results

Wise¹,

Breza²,

Harwood³

et al. 1992

Proceedings of the Ocean Drilling Program

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“…The top 9 m quartz grains are characterised by high occurrence of angular grains with the dominance of mechanical features consisting of fracture plates, meandering ridges, upturned plates, edge abrasion and conchoidal features associated with straight arcuate parallel steps and scratches (Figures 3a and 3b). These features indicate that quartz grains have undergone rapid deposition [35] which were derived from the nearby crystalline rocks [3] and transported under fluvial environment [22] of high-energy condition [1]. This reflected in the sediment texture showing angular grains of medium to fine sand deposited under violent to most violent environment (Figure 4).…”

Section: Discussionmentioning

confidence: 99%

“…The criteria for distinguishing the mechanical and chemical features of quartz grains and their implications have been established [1,2]. These features delineating the provenance and transportation history [3].…”

Section: Introductionmentioning

confidence: 99%

Depositional History of Coastal Plain Sediments, Southern Kerala, South West India

Ti¹,

Tn²,

Nagendra³

2016

J Earth Sci Clim Change

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“…Samples were coated with carbon for SEM analysis only. Surface feature categories were based on Krinsley and Donahue (1968), Margolis and Kennett (1971), and Margolis and Krinsley (1974).…”

Section: Methodsmentioning

confidence: 99%

“…Sand-sized quartz grains from late Miocene, early Pliocene, late Pliocene, and Pleistocene age sediments were examined under the SEM to observe the intensity, if any, of mechanical abrasion. The SEM examination of the quartz grains revealed surface features considered diagnostic of glacially worked grains (Krinsley and Donahue, 1968;Margolis and Kennett, 1971;Margolis and Krinsley, 1974), such as extreme angularity, high relief, large-and small-scale conchoidal fractures, dish-shaped conchoidal fractures, steplike fractures, and arc-step fractures . Throughout the entire sequence, the intensity of mechanical abrasion observed on the quartz grains appears to be the same.…”

Section: Description Of Ice-rafted Debrismentioning

confidence: 99%

High-Resolution Study of Neogene Ice-Rafted Debris, Site 751, Southern Kerguelen Plateau

James¹

1992

Proceedings of the Ocean Drilling Program

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Environmental Interpretation of Sand Grain Surface Textures by Electron Microscopy

Cited by 215 publications

References 0 publications

Paleogene Glacial History of Antarctica in Light of Leg 120 Drilling Results

Paleogene Glacial History of Antarctica in Light of Leg 120 Drilling Results

Depositional History of Coastal Plain Sediments, Southern Kerala, South West India

High-Resolution Study of Neogene Ice-Rafted Debris, Site 751, Southern Kerguelen Plateau

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