Global ETD Search
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Showing 1 to 11 of 11 for “"Diamictite"”.
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Geochronological constraints on the Trinity diamictite in Newfoundland : Implications for Ediacaran glaciation
… the Gaskiers glaciation. Recent recognition of a diamictite facies on the nearby Bonavista Peninsula correlative with the Gaskiers diamictite has allowed for new, high-precision geochronological constraints on the Gaskiers glaciation and constrains the duration of the event to less than 390 ±320 …
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Geochemistry of the Sykesville diamictite in central Maryland: an investigation of clast-matrix activity during metamorphism with tectonic implications
The Sykesville diamictite is part of the Wissahickon sequence, a polydeformed and metamorphosed sequence of questionable age in the Central Appalachian Piedmont. It occurs in association with thrust stacks of volcanic and mafic units of the Baltimore Mafic Complex and Potomac Valley Sequence in …
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Chemostratigraphic correlation and Pb-Pb dating of carbonate sequences in the external Gariep belt and Kango inlier of the Saldania belt in Namibia and South Africa
… by an intimate association of glaciogenic diamictite with marine carbonate deposits, indicating possibly rapid climatic changes from icehouse to greenhouse conditions. Such sequences also occur in the Pan-African Gariep Belt and in the Kango inlier of the Saldania Belt in Namibia and South …
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Sedimentology of the Squantum ‘Tillite’, Boston Basin, USA: Modern Analogues and Implications for the Paleoclimate during the Gaskiers Glaciation (c. 580 Ma)
… of volcanoes and arc-type basins. ‘Till-like’ diamictite horizons identified within these basins have been used as evidence for a ‘Snowball Earth-type’ glaciation at 580 Ma. However, others argue that these deposits are non-glacial debris flow deposits. To test the non-glacial interpretation of …
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Investigating potential climatic cycles in glacially-influenced rhythmites of the upper Gowganda Formation using geochemical, sedimentological and spectral analyses
… a glaciogenic depositional environment: 1) diamictite, 2) contorted argillite, 3) interlaminated siltstone and sandstone, 4) interbedded siltstone and claystone, 5) sandstone, 6) siltstone, 7) interbedded coarse-grained and fine-grained siltstone, and 8) wavy argillite. Major, trace, and …
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Triple oxygen isotope measurements in chert: insights into the Snowball Earth glaciations
… sequence immediately underlying a Cryogenian diamictite to better understand this relationship, particularly the chemistry of subglacial meltwater. Using triple oxygen isotope measurements, clumped isotope palaeothermometry, uranium-lead geochronology, and SEM/EDS and XRD analyses, we present …
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The stratigraphy and structural evolution of the late Proterozoic Gariep belt in the Sendelingsdrif-Annisfontein area, northwestern Cape Province
… Sequence, consisting of a widespread glaciogenic diamictite (Sendelingsdrif Formation) and a near-basal banded iron formation (Jakkalsberg Formation). A deep-water elastic unit, the Holgat Sequence, was laid down during the early stage of the lower Nama transgression.
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The Middle Ordovician Fincastle conglomerate north of Roanoke, Virginia and its implications for Blue Ridge tectonism
… shale. Each conglomerate zone may grade up into diamictite or graywacke which, in turn, grades upward into shale. Clasts of well-foliated basement gneiss, vein quartz, quartz pebble conglomerate, sandstone and carbonate clasts were derived from the complementary Blue Ridge anticlinorium and …
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Geochemical and Paleontological investigations of the Neoproterozoic-Cambrian Transition: Case Studies on geochemical clast provenance, emerging paleo redox proxies, and ambiguous dubiofossils
… examines the carbonate clasts from a glacial diamictite deposited at the end of the Cryogenian Period in South China. By determining the source locality of those carbonate clasts using stable carbon and oxygen isotope compositions, we can better understand the extent of the Marinoan Glaciation …
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The Mall Bay Formation (Ediacaran) and the Protracted Onset of the Gaskiers Glaciation in Newfoundland, Canada
… Just below the top of the formation, glaciogenic diamictite debrites were introduced into the slope setting, perhaps signaling the arrival of the ice sheet margin at the shelf edge in proximity to the study area, causing a significant increase in slope instability due to loading of glaciogenic …
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Contributions to the Neoproterozoic Geobiology
… of the Zhamoketi cap dolostone atop the Tereeken diamictite in the Quruqtagh area, eastern Chinese Tianshan. Our new data indicate that carbonate associated sulfate (CAS) abundance decreases rapidly in the basal cap dolostone and δ34SCAS composition varies between +9â ° and +15â ° in the lower 2.5 …