scholarly journals High resolution 3D confocal microscope imaging of volcanic ash particles

2017 ◽  
Vol 590-591 ◽  
pp. 838-842 ◽  
Author(s):  
David Wertheim ◽  
Gavin Gillmore ◽  
Ian Gill ◽  
Nick Petford
Keyword(s):  
High Resolution ◽  
Volcanic Ash ◽  
Confocal Microscope ◽  
Microscope Imaging

In-Vivo Histopathology Via Standard Endoscopes? First Results of a New High-Resolution Miniprobe-Based Confocal Microscope

2007 ◽  
Vol 65 (5) ◽  
pp. AB126 ◽  
Author(s):  
Valentin Becker ◽  
Claus Hann Von Weyhern ◽  
Christian Prinz ◽  
Roland M. Schmid ◽  
Alexander Meining
Keyword(s):  
High Resolution ◽  
Confocal Microscope ◽  
First Results

Astronomical dating of two Pliocene alkaline volcanic ash layers in the Capo Rossello area (southern Sicily, Italy): implications for the beginning of the rifting in the Sicily Channel

2009 ◽  
Vol 180 (2) ◽  
pp. 95-104 ◽  
Author(s):  
Antonio Caruso ◽  
Paolo Censi ◽  
Pietro Aricò ◽  
Carmelina Meli ◽  
Mario Sprovieri
Keyword(s):  
High Resolution ◽  
Late Pleistocene ◽  
Volcanic Activity ◽  
Volcanic Ash ◽  
South Coast ◽  
Sedimentary Sequences ◽  
Volcanic Source ◽  
Sicily Channel ◽  
The One ◽  
Middle Pliocene

Abstract Two volcaniclastic ash layers (AL1 and AL2) are intercalated throughout the middle Pliocene sedimentary sequences of Punta Piccola and Capo Rossello exposed along the south coast of Sicily (Italy). Astronomical calibration of the Punta Piccola section provided an age of 2.676 Ma for the deposition of the AL1 layer. The high-resolution bio-cyclostratigraphy of the Capo Rossello section, in combination with detailed correlations with previously astronomically calibrated coeval sequences, provided an age of 2.225 Ma for the deposition of the AL2 layer. Mineralogical, petrographical and geochemical results from the two volcaniclastic layers suggest a Na-alkaline differentiated magmatism for the volcanic source, similar to the one which formed the alkaline rocks of the island of Pantelleria (Sicily Channel). These results indicate that isolated volcanic activity and/or early differentiated magmatic events may have occurred in the area of the Sicily channel well before the well-known late Pleistocene volcanic activity.

scholarly journals New Chronostratigraphic Constraints on the Lower Jurassic Pliensbachian–Toarcian Boundary at Chacay Melehue (Neuquén Basin, Argentina)

2021 ◽  
Author(s):  
Aisha H. Al-Suwaidi ◽  
Micha Ruhl ◽  
Hugh C. Jenkyns ◽  
Susana E. Damborenea ◽  
Miguel O. Manceñido ◽  
...  
Keyword(s):  
High Resolution ◽  
Carbon Isotope ◽  
Volcanic Ash ◽  
Lower Jurassic ◽  
Zircon Geochronology ◽  
Organic Carbon Isotope ◽  
Carbon Isotope Excursion ◽  
Isotope Record ◽  
Age Model ◽  
Zonal Boundary

Abstract The Pliensbachian–Toarcian boundary interval is characterized by a ~3‰ negative carbon-isotope excursion (CIE) in organic and inorganic marine and terrestrial archives from sections in Europe, such as Peniche (Portugal) and Hawsker Bottoms, Yorkshire (UK). A new high-resolution organic-carbon isotope record, illustrating the same chemostratigraphic feature, is presented from the Southern Hemisphere Arroyo Chacay Melehue section, Chos Malal, Argentina, corroborating the global significance of this disturbance to the carbon cycle. The negative carbon-isotope excursion, mercury and organic-matter enrichment is accompanied by high-resolution ammonite and nannofossil biostratigraphy together with U-Pb CA-ID-TIMS geochronology derived from intercalated volcanic ash beds. A new age of ~183.71 ± 0.40/-0.51 Ma for the Pliensbachian–Toarcian boundary, and 182.77 +0.11/-0.21 for the tenuicostatum–serpentinum zonal boundary, is assigned based on high-precision U-Pb zircon geochronology and a Bayesian Markov chain Monte Carlo (MCMC) stratigraphic age model.

scholarly journals High-resolution stalagmite stratigraphy supports the Late Holocene tephrochronology of southernmost Patagonia

2021 ◽  
Author(s):  
Björn Klaes ◽  
Gerhard Wörner ◽  
Katrina Kremer ◽  
Klaus Simon ◽  
Denis Scholz ◽  
...  
Keyword(s):  
High Resolution ◽  
South America ◽  
Large Volume ◽  
Critical Region ◽  
Late Holocene ◽  
Volcanic Ash ◽  
Explosive Volcanism ◽  
Geochemical Data ◽  
Karst Cave ◽  
Icp Ms

Abstract Volcanic ash layers are important markers for the chronostratigraphy of paleoclimate and paleoenvironmental archives at the southern tip of South America. However, this requires that tephras are well-dated. We report geochemical data from the MA1 stalagmite formed in a non-karst cave near Mt. Burney volcano in southernmost Patagonia (~53°S). High-resolution LA-ICP-MS analyses, SEM imagery, and NanoSIMS enable to identify volcanogenic signals during the last 4.5 kyrs BP from sub-annual trace element variations and tephra particles in distinct laminae. The new 230Th/U-chronology of MA1 provides precise dating of tephra from Mt. Burney (MB) and Aguilera (A) at 4216 +93/−193 yrs BP (MB2), 2291 ± 33 yrs BP (MB3), 853 +41/−60 yrs BP (MB4) and 2978 +91/−104 yrs BP (A1). This unique high-resolution record of MA1 holds potential to date further eruptions from Southern Andean volcanoes for the tephrochronology in this critical region, and potentially also large-volume explosive volcanism off South America.

scholarly journals Precise age for the Permian-Triassic boundary in South China from high precision U-Pb geochronology and Bayesian age-depth modelling

2016 ◽  
Author(s):  
Björn Baresel ◽  
Hugo Bucher ◽  
Morgane Brosse ◽  
Fabrice Cordey ◽  
Kuang Guodun ◽  
...  
Keyword(s):  
High Resolution ◽  
South China ◽  
Volcanic Ash ◽  
Proof Of Concept ◽  
Triassic Boundary ◽  
Quantitative Evidence ◽  
Age Model ◽  
Stratotype Section ◽  
Permian Triassic Boundary ◽  
Environmental Proxies

Abstract. This study is based on zircon U-Pb ages of 12 volcanic ash layers and volcanogenic sandstones from two marine sections with conformable formational Permian-Triassic boundaries (PTB) in the Nanpanjiang Basin (South China). Our dates of single, thermally annealed and chemically abraded zircons bracket the PTB in Dongpan and Penglaitan and provide the basis for a first proof-of-concept study utilizing a Bayesian chronology model comparing the three sections of Dongpan, Penglaitan and the Global Stratotype Section and Point (GSSP) Meishan. Our Bayesian modeling demonstrates that the formational boundaries in Dongpan (251.938 ± 0.029 Ma), Penglaitan (251.982 ± 0.031 Ma) and Meishan (251.956 ± 0.033 Ma) are synchronous within analytical uncertainty of ca. 30 ka. It also provides quantitative evidence that the ages of the paleontologically defined boundaries, based on conodont Unitary Associations zones in Meishan and on macrofaunas in Dongpan, are identical and coincide with the age of the formational boundaries. The age model also confirms the extreme condensation around the PTB in Meishan, which distorts the projection of any stratigraphic points or intervals onto other more expanded sections by means of Bayesian age-depth models. Dongpan and Penglaitan possess significantly higher sedimentation rates and thus offer a greater potential for high resolution studies of environmental proxies and correlations around the PTB than Meishan. This study highlights the power of high-resolution radio-isotopic ages that allow a robust intercalibration of patterns of biotic changes and fluctuating environmental proxies and will help recognizing their global, regional or local significance.

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