Topic
Dropstone
About: Dropstone is a research topic. Over the lifetime, 60 publications have been published within this topic receiving 1768 citations.
Papers published on a yearly basis
Papers
TL;DR: Dropstone, dump, and grounding structures, resulting from the melt-out of debris contained in floating and grounded icebergs, are described from a Pleistocene ice-marginal, glacio-lacustrine sequence in Scotland.
Abstract: Dropstone, dump, and grounding structures, resulting from the melt-out of debris contained in floating and grounded icebergs, are described from a Pleistocene ice-marginal, glacio-lacustrine sequence in Scotland. Dropstones display bending penetration, rucking, and complete rupture of stratum occurring beneath them, and onlap above them, with the degree of deformation varying as a function of the size, shape, and axial disposition of the clast and of the sediment type into which they fell. Dump structures are conical mounds of gravel or diamict formed by the break-up and overturning of dirt-laden icebergs and the consequent release of large quantities of debris to the lake floor. Grounding structures are caused by the grounding of icebergs, the down-warping of underlying lake-floor se iment, and the subsequent in situ melt-out of contained debris to form isolated troughs of diamict.
233 citations
TL;DR: A shipboard analysis of the 1,183m sedimentary section recovered at Site 918 in the Irminger Basin during Ocean Drilling Program Leg 152 revealed material of glacial origin (diamictons, ice-rafted debris (IRD) and dropstones) as deep as 543 m below sea floor (bsf).
137 citations
TL;DR: In the highland snowfields of northeastern Spitsbergen (Svalbard) as mentioned in this paper, the oldest sediments in the Polarisbreen Group compose the Elbobreen Formation (c. 400 m), which is divided into four laterally persistent members.
111 citations
TL;DR: In this paper, the composition of ice-rafted debris (IRD) >250 gm was analyzed quantitatively by grain counting in five sediment cores from the western central Arctic Ocean and compared with the composition from NW Canada in order to determine the dropstone origin and to reconstruct the Pleistocene ice drillways and surface currents.
Abstract: The composition of Pleistocene ice-rafted debris (IRD) >250 gm was analyzed quantitatively by grain counting in five sediment cores t¾om the western central Arctic Ocean and compared with the composition of till clasts from NW Canada in order to determine the dropstone origin and to reconstruct the Pleistocene ice drillways and surface currents. The IRD composition alternates repeatedly between carbonate- and quartz-dominated assemblages, along with metamorphic and igneous rocks, clastic rocks, and some chert. The highest quartz content is found on the Alpha Ridge, while carbonate percentages are highest on the Northwind Ridge (NWR) and the Chukchi Cap. The source for the carbonates is the area around Banks and Victoria Islands and parts of northern Canada. Quartz most likely originated from the central Queen Elizabeth Islands. IRD on the southeastern Alpha Ridge is dominated by mafic crystalline rocks from northern Ellesmere Island and northern Greenland. At least six major glacial intervals are identified within the last 1 million years, during which icebergs drifted toward the west in the Beaufort Sea, straight northward in the central Arctic Ocean, and northeastward on the SE Alpha Ridge.
101 citations
TL;DR: A single layer striated boulder pavement is superbly exposed in the Hoyada Verde Formation of the Calingasta-Uspallata and Leoncito Formation of western Argentina as discussed by the authors, where the pavements are overlain by thin, laterally discontinuous diamictite beds with striated clasts, some of them bullet-shaped.
84 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 2 |
| 2020 | 2 |
| 2019 | 2 |
| 2017 | 2 |
| 2016 | 5 |
| 2015 | 1 |