Retreat History of the Gerlache-Boyd Ice Stream, Northern Antarctic Peninsula: An Ultra-High Resolution Acoustic Study of the Deglacial and Post-Glacial Sediment Drape

2013 ◽  
pp. 183-194 ◽  
Author(s):  
Verónica Willmott ◽  
Miquel Canals ◽  
José L. Casamor
Keyword(s):  
High Resolution ◽  
Antarctic Peninsula ◽  
Glacial Sediment ◽  
Acoustic Study ◽  
Ice Stream ◽  
History Of

Cosmogenic 10Be exposure dating of glacial erratics on Horseshoe Island in western Antarctic Peninsula confirms rapid deglaciation in the Early Holocene

2019 ◽  
Vol 31 (6) ◽  
pp. 319-331 ◽  
Author(s):  
Attila Çiner ◽  
Cengiz Yildirim ◽  
M. Akif Sarikaya ◽  
Yeong Bae Seong ◽  
Byung Yong Yu
Keyword(s):  
Antarctic Peninsula ◽  
Late Quaternary ◽  
Western Antarctic Peninsula ◽  
Sea Levels ◽  
Exposure Dating ◽  
Ice Stream ◽  
Marguerite Bay ◽  
History Of ◽  
Cosmogenic 10Be ◽  
Exposure Ages

AbstractThe rapid warming observed in the western Antarctic Peninsula gives rise to a fast disintegration of ice shelves and thinning and retreat of marine-terminating continental glaciers, which is likely to raise global sea levels in the near future. In order to understand the contemporary changes in context and to provide constraints for hindcasting models, it is important to understand the Late Quaternary history of the region. Here, we build on previous work on the deglacial history of the western Antarctic Peninsula and we present four new cosmogenic 10Be exposure ages from Horseshoe Island in Marguerite Bay, which has been suggested as a former location of very fast ice stream retreat. Four samples collected from erratic pink granite boulders at an altitude of ~80 m above sea level yielded ages that range between 12.9 ± 1.1 ka and 9.4 ± 0.8 ka. As in other studies on Antarctic erratics, we have chosen to report the youngest erratic age (9.4 ± 0.8 ka) as the true age of deglaciation, which confirms a rapid thinning of the Marguerite Trough Ice Stream at the onset of Holocene. This result is consistent with other cosmogenic age data and other proxies (marine and lacustrine 14C and optically stimulated luminescence) reported from nearby areas.

scholarly journals Combined high-resolution seismostratigraphic and morphobathymetric analysis reveals glacial history of the northwestern Chukchi margin, Arctic Ocean

2020 ◽  
Author(s):  
Sookwan Kim ◽  
Leonid Polyak ◽  
Young Jin Joe ◽  
Frank Niessen ◽  
Hyoung Jun Kim ◽  
...  
Keyword(s):  
High Resolution ◽  
Arctic Ocean ◽  
Glacial History ◽  
History Of

scholarly journals High resolution integrated microbiostratigraphy of the Lower Jurassic (late Pliensbachian–early Toarcian) of central Italy

1998 ◽  
Vol 17 (2) ◽  
pp. 153-172 ◽  
Author(s):  
Raffaella Bucefalo Palliani ◽  
Emanuela Mattioli
Keyword(s):  
High Resolution ◽  
Evolutionary History ◽  
Central Italy ◽  
Lower Jurassic ◽  
High Potential ◽  
Calcareous Nannofossils ◽  
Calcareous Nannofossil ◽  
Dinoflagellate Cyst ◽  
History Of ◽  
Global Events

Abstract. The integrated use of calcareous nannofossil and dinoflagellate cyst events in a study of the late Pliensbachian–early Toarcian interval in central Italy has yielded a high resolution biostratigraphy. The use of both the first and last occurrences of selected taxa belonging to the two phytoplankton groups allows the dating of the sediments with a very refined detail, even when lithologies are unfavourable to the preservation of one fossil group. The evolutionary history of calcareous nannofossils and dinoflagellate cysts during the early Jurassic and its links with global events are responsible for the high potential of this integrated biostratigraphy.

scholarly journals Natural History of Endoscopic Third Ventriculostomy in Adults: Serial Evaluation with High-Resolution CISS

2018 ◽  
Vol 39 (12) ◽  
pp. 2231-2236 ◽  
Author(s):  
M. Trelles ◽  
A.K. Ahmed ◽  
C.H. Mitchell ◽  
I. Josue-Torres ◽  
D. Rigamonti ◽  
...  
Keyword(s):  
High Resolution ◽  
Natural History ◽  
Endoscopic Third Ventriculostomy ◽  
Third Ventriculostomy ◽  
History Of ◽  
Serial Evaluation

scholarly journals Association of post-traumatic communication of endocranium and nasal cavity with recurrent meningoencephalitis without rhinorrhea

2010 ◽  
Vol 67 (11) ◽  
pp. 945-948 ◽  
Author(s):  
Djula Djilvesi ◽  
Petar Vulekovic ◽  
Tomislav Cigic ◽  
Zeljko Kojadinovic ◽  
Vladimir Papic ◽  
...  
Keyword(s):  
Case Report ◽  
Head Injury ◽  
High Resolution ◽  
Ct Scans ◽  
Direct Impact ◽  
Skull Base Fracture ◽  
Therapeutic Procedures ◽  
History Of ◽  
Post Traumatic ◽  
Transnasal Endoscopic Surgery

Introduction. A gunshot head injury, characterized by a huge intensity of mechanical force, in addition to the direct tissue damage at the location of direct impact, may cause a skull and skull base fracture, distant from the the point of direct impact, which could be further complicated by creating a communication between endocranium and nasal/paranasal cavities. Such cases pose a great diagnostic and therapeutic challenge for every clinician. Case report. The patient is presented with the history of a perforating gunshot head injury six years ago, with recurrent attacks of meningoencephalitis subsequently, without rhinorrhea. By using high resolution CT scans, previous traumatic skull injury was verified and a fissure in the frontoethmoidal region, far from the point of direct impact, was detected. The patient underwent transnasal endoscopic surgery, in order to seal the communication on skull basis. The patient did not suffer from meningoencephalitis during the next two years. Conclusion. In the cases with late occurrence of posttraumatic meningoencephalitis with no signs of rhinorrhea, a possibility of an existing communication between intracranial and nasal cavities should be considered, as well. By applying modern diagnostic and therapeutic procedures such communication should be precisely located and sealed.

scholarly journals Thermal History of Matrix Forsterite Grains from Murchison Based on High-resolution Tomography

2021 ◽  
Vol 922 (2) ◽  
pp. 256
Author(s):  
Giulia Perotti ◽  
Henning O. Sørensen ◽  
Henning Haack ◽  
Anja C. Andersen ◽  
Dario Ferreira Sanchez ◽  
...  
Keyword(s):  
High Resolution ◽  
Electron Density ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Density Maps ◽  
Thermally Processed ◽  
The Matrix ◽  
History Of ◽  
Chondrule Formation

Abstract Protoplanetary disks are dust- and gas-rich structures surrounding protostars. Depending on the distance from the protostar, this dust is thermally processed to different degrees and accreted to form bodies of varying chemical compositions. The primordial accretion processes occurring in the early protoplanetary disk such as chondrule formation and metal segregation are not well understood. One way to constrain them is to study the morphology and composition of forsteritic grains from the matrix of carbonaceous chondrites. Here, we present high-resolution ptychographic X-ray nanotomography and multimodal chemical microtomography (X-ray diffraction and X-ray fluorescence) to reveal the early history of forsteritic grains extracted from the matrix of the Murchison CM2.5 chondrite. The 3D electron density maps revealed, at unprecedented resolution (64 nm), spherical inclusions containing Fe–Ni, very little silica-rich glass and void caps (i.e., volumes where the electron density is consistent with conditions close to vacuum) trapped in forsterite. The presence of the voids along with the overall composition, petrological textures, and shrinkage calculations is consistent with the grains experiencing one or more heating events with peak temperatures close to the melting point of forsterite (∼2100 K), and subsequently cooled and contracted, in agreement with chondrule-forming conditions.

scholarly journals HERMES – An instrument of the future

2009 ◽  
Vol 5 (S262) ◽  
pp. 448-449 ◽  
Author(s):  
Elizabeth Wylie-de Boer ◽  
Kenneth Freeman
Keyword(s):  
Star Formation ◽  
High Resolution ◽  
Resolving Power ◽  
Individual Stars ◽  
Elemental Abundances ◽  
The Future ◽  
The Galaxy ◽  
History Of ◽  
High Resolution Spectrometer ◽  
Resolution Spectrometer

AbstractHERMES is a new, multi-object high resolution spectrometer for the 3.9m Anglo Australian Telescope, using the existing 2dF positioner. The primary goal of the HERMES survey is to unravel the history of the Galaxy from detailed elemental abundances for about 1.2 million individual stars. The HERMES chemical tagging survey concentrates on the 5000 to 8000 Å window at a resolving power of 30,000 in order to identify dissolved star formation aggregates and ascertain the importance of mergers throughout the history of the Galaxy.

Historical review, catalog of type specimens and online database of the ichthyology collection of the Instituto de Ciencias Naturales of the Universidad Nacional de Colombia (ICN-MHN)

Zootaxa ◽  
2018 ◽  
Vol 4478 (1) ◽  
pp. 1
Author(s):  
JOSÉ IVAN MOJICA ◽  
HENRY D. AGUDELO-ZAMORA
Keyword(s):  
High Resolution ◽  
Historical Review ◽  
Online Database ◽  
Type Specimens ◽  
History Of ◽  
First Time

For the first time, the catalog of type specimens of ICN-MHN is presented with high resolution photographs. The catalog lists 87 species in 161 lots and includes 41 holotypes, 3 neotypes, and 117 lots of paratypes. Some doubts remain about type specimens of some species described by Miles and Dahl that were supposedly deposited at ICN-MHN. The history of the collection is reconstructed and valuable specimens once considered lost or destroyed have been rediscovered. The botanical and zoological collections of the ICN can be consulted online (http://www.biovirtual.unal.edu.co). 

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