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ejecta

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Journal Article
Published: 16 October 2020
Journal of the Geological Society (2021) 178 (1): jgs2020-056.
... of shocked quartz led to the hypothesis that the Stac Fada Member represents part the continuous ejecta blanket of a meteorite impact crater, the location of which was, and remains, unknown. In this paper, we confirm the presence of shock-metamorphosed and -melted material in the Stac Fada Member; however...
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Journal Article
Journal: Geology
Published: 07 October 2020
Geology (2021) 49 (2): 201–205.
... compression. However, there is no broad consensus among empirical, experimental, and theoretical studies on the nature of the polymorphic transformation. Here we decipher a multistage history of reidite growth recorded in a zircon grain in distal impact ejecta (offshore northeastern United States) from the ca...
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Journal Article
Journal: Economic Geology
Published: 01 May 2020
Economic Geology (2020) 115 (3): 505–525.
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Journal Article
Published: 17 January 2020
Journal of the Geological Society (2020) 177 (2): 449–451.
... of the Stac Fada Member. Still more conclusively, a metre-scale gneiss clast in the spallation ejecta layer beneath the Stac Fada Member is abruptly truncated at the unconformity surface ( Fig. 2 ). The apparent thickness (>30 m) of the Stac Fada Member here reflects a dip slightly less steep than...
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Journal Article
Published: 17 January 2020
Journal of the Geological Society (2020) 177 (2): 452–454.
... and 2 ). Our observations of the disrupted pre-existing sedimentary strata suggest that little information can be gained on the direction the impact ejecta travelled. The sandstone raft noted by Simms does indeed have over-steepened beds but it is unclear whether it is still attached to the strata...
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Journal Article
Published: 13 December 2019
Journal of the Geological Society (2020) 177 (2): 447.
... ) was based largely on field observations that, amongst other things, indicated that the Stac Fada Member impact ejecta preserved at outcrop had come from the east (despite claims to the contrary by others; Amor et al. 2008 , 2019 ). When subsequently I became aware of the LGL I realized that its location...
Journal Article
Published: 13 December 2019
Journal of the Geological Society (2020) 177 (2): 443–446.
... of the Stoer Group of NW Scotland as a proximal ejecta blanket of late Mesoproterozoic age ( Amor et al. 2008 ) has led to the search for the impact crater from which it originated. One prominent suggestion has been that this crater lies buried beneath east-central Sutherland, broadly centred on the village...
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Journal Article
Published: 01 April 2019
American Mineralogist (2019) 104 (4): 611–614.
... uncertain. Hydrogen has profound effects on properties and processes on microscopic-to-global scales. Here we report the discovery of the first hydride (VH 2 ) ever reported in nature. This phase has been found in the ejecta of Cretaceous pyroclastic volcanoes on Mt Carmel, N. Israel, which include abundant...
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Series: GSA Field Guide
Published: 10 December 2018
DOI: 10.1130/2018.0051(17)
EISBN: 9780813756516
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Journal Article
Published: 27 November 2018
Journal of the Geological Society (2019) 176 (2): 209–224.
... and remobilization of ejecta blankets from major meteorite impact events, before returning to background after some hundreds to thousands of years. We review the 44 largest confirmed craters and evaluate the potassium feldspar content of their target rocks, which range from c. 0 to >30%. By combining crater size...
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Journal Article
Journal: Geology
Published: 19 July 2018
Geology (2018) 46 (9): 739–742.
.... The actual mechanism whereby coesite forms in these symplectic regions, i.e., direct transformation from quartz or crystallization from hot silica melts jetted into the collapsing pore ( Kieffer et al., 1976 ), is still unclear. Symplectic regions were identified in shocked sandstone ejecta samples...
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Journal Article
Journal: Geology
Published: 20 December 2017
Geology (2018) 46 (3): 203–206.
.... , and Koeberl , C. , 2006 , Australasian microtektites and associated impact ejecta in the South China Sea and the Middle Pleistocene supereruption of Toba : Meteoritics & Planetary Science , v. 41 , p. 305 – 326 , https://doi.org/10.1111/j.1945-5100.2006.tb00211.x . Glass , B.P...
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Journal Article
Journal: Geology
Published: 12 December 2017
Geology (2018) 46 (2): 171–174.
.... However, it is highly unusual to find unmelted crystals from the actual impactor within an ejecta layer. Here we detail the first recorded occurrence of vanadium-rich osbornite (TiVN) on Earth, from two sites on Skye, northwest Scotland, which are interpreted as part of a meteoritic ejecta layer. TiVN has...
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Journal Article
Journal: Geology
Published: 03 October 2017
Geology (2017) 45 (12): 1063–1066.
... is reached, ballistic trajectories are calculated for ejecta using tracer velocities. The trajectories determine when and where material will be emplaced outside of the elliptical transient crater. Inside the rim of the final ∼2500-km-diameter elliptical crater but outside the transient crater, post...
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Journal Article
Published: 14 August 2017
Geological Magazine (2019) 156 (1): 1–24.
... . 3.7 km diameter crater with a well-preserved ejecta blanket. It has been hypothesized to be either of impact or volcanic origin in our previous work. Observations during our 2007 expedition and related sample analyses give further support for an impact origin. The evidence includes the presence...
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Journal Article
Journal: Geology
Published: 01 October 2016
Geology (2016) 44 (10): 811–814.
... of an eruption, explosion mechanisms, and ultimately hazards associated with an eruption, it is important to recognize the contribution of recycled clasts to ejecta deposits ( Houghton and Smith, 1993 ). Recycling can involve individual juvenile or lithic clasts, clasts composed of a combination of the two...
Journal Article
Journal: Geology
Published: 01 July 2016
Geology (2016) 44 (7): 519–522.
...Jennifer L. Whitten; Bruce A. Campbell Abstract Ejecta from impact craters on Venus are a major source of fine-grained materials across the planet, and crater spatial distribution has been studied as a guide to the relative age and resurfacing rates of large regions. Of particular interest...
Journal Article
Journal: Geology
Published: 01 March 2016
Geology (2016) 44 (3): 195–198.
... and film of other Surtseyan eruptions. Together, these lend new support to the picture of Surtseyan volcanism described by Kokelaar (1983) , who inferred the primary interaction to be not between magma and water per se, but between magma and a water-saturated slurry of previously erupted ejecta that fills...
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Journal Article
Published: 01 November 2015
American Mineralogist (2015) 100 (11-12): 2426–2442.
... produced a range of experimental and theoretical data sets on bubble nucleation, growth, and coalescence in magmatic systems. A robust experimental database is required to calibrate (theoretical and empirical) modeling approaches, which allow the calculation of magma ascent rates from volcanic ejecta...
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Series: GSA Special Papers
Published: 01 October 2015
DOI: 10.1130/2015.2518(03)
... This study compares results of crater diameter, shape, ejecta morphologies, and interior morphologies in the northern hemisphere of Mars between older results reported from a Viking -derived crater catalog and a new crater catalog obtained from analysis of higher-resolution data sets...