scholarly journals Deep drilling of intact ocean crust: harnessing past lessons to inform future endeavors

2012 ◽  
Author(s):  
Keyword(s):  
Deep Drilling ◽  
Ocean Crust

Deep Drilling Results in the Atlantic Ocean: Ocean Crust

1979 ◽  
Author(s):  
Manik Talwani ◽  
Christopher G. Harrison ◽  
Dennis E. Hayes
Keyword(s):  
Atlantic Ocean ◽  
Deep Drilling ◽  
Ocean Crust

The ICDP-USGS Deep Drilling Project in the Chesapeake Bay impact structure: Results from the Eyreville Core Holes

2009 ◽  
Author(s):  
Gregory S. Gohn ◽  
Christian Koeberl ◽  
Kenneth G. Miller ◽  
Wolf Uwe Reimold
Keyword(s):  
Chesapeake Bay ◽  
Impact Structure ◽  
Deep Drilling ◽  
Drilling Project

scholarly journals Rapid alteration of fractured volcanic conduits beneath Mt Unzen

2021 ◽  
Vol 83 (5) ◽  
Author(s):  
Tim I. Yilmaz ◽  
Fabian B. Wadsworth ◽  
H. Albert Gilg ◽  
Kai-Uwe Hess ◽  
Jackie E. Kendrick ◽  
...  
Keyword(s):  
Country Rock ◽  
Geophysical Methods ◽  
Hydrothermal Fluids ◽  
Deep Drilling ◽  
Stress Regime ◽  
Argillic Alteration ◽  
Carbon And Oxygen Isotope ◽  
Propylitic Alteration ◽  
Indirect Information

AbstractThe nature of sub-volcanic alteration is usually only observable after erosion and exhumation at old inactive volcanoes, via geochemical changes in hydrothermal fluids sampled at the surface, via relatively low-resolution geophysical methods or can be inferred from erupted products. These methods are spatially or temporally removed from the real subsurface and thus provide only indirect information. In contrast, the ICDP deep drilling of the Mt Unzen volcano subsurface affords a snapshot into the in situ interaction between the dacitic dykes that fed dome-forming eruptions and the sub-volcanic hydrothermal system, where the most recent lava dome eruption occurred between 1990 and 1995. Here, we analyse drill core samples from hole USDP-4, constraining their degree and type of alteration. We identify and characterize two clay alteration stages: (1) an unusual argillic alteration infill of fractured or partially dissolved plagioclase and hornblende phenocryst domains with kaolinite and Reichweite 1 illite (70)-smectite and (2) propylitic alteration of amphibole and biotite phenocrysts with the fracture-hosted precipitation of chlorite, sulfide and carbonate minerals. These observations imply that the early clay-forming fluid was acidic and probably had a magmatic component, which is indicated for the fluids related to the second chlorite-carbonate stage by our stable carbon and oxygen isotope data. The porosity in the dyke samples is dominantly fracture-hosted, and fracture-filling mineralization is common, suggesting that the dykes were fractured during magma transport, emplacement and cooling, and that subsequent permeable circulation of hydrothermal fluids led to pore clogging and potential partial sealing of the pore network on a timescale of ~ 9 years from cessation of the last eruption. These observations, in concert with evidence that intermediate, crystal-bearing magmas are susceptible to fracturing during ascent and emplacement, lead us to suggest that arc volcanoes enclosed in highly fractured country rock are susceptible to rapid hydrothermal circulation and alteration, with implications for the development of fluid flow, mineralization, stress regime and volcanic edifice structural stability. We explore these possibilities in the context of alteration at other similar volcanoes.

First glaciological investigations at Ridge B, central East Antarctica

2021 ◽  
pp. 1-10
Author(s):  
Alexey A. Ekaykin ◽  
Alexey V. Bolshunov ◽  
Vladimir Ya. Lipenkov ◽  
Mirko Scheinert ◽  
Lutz Eberlein ◽  
...  
Keyword(s):  
East Antarctica ◽  
Snow Density ◽  
Deep Drilling ◽  
Surface Mass ◽  
Annual Variations ◽  
First Results ◽  
Vostok Station ◽  
Water Stable Isotope ◽  
Isotope Content ◽  
Firn Core

Abstract The region of Ridge B in central East Antarctica is one of the last unexplored parts of the continent and, at the same time, ranks among the most promising places to search for Earth's oldest ice. In January 2020, we carried out the first scientific traverse from Russia's Vostok Station to the topographical dome of Ridge B (Dome B, 3807 m above sea level, 79.02°S, 93.69°E). The glaciological programme included continuous snow-radar profiling and geodetic positioning along the traverse's route, installation of snow stakes, measurements of snow density, collection of samples for stable water isotope and chemical analyses and drilling of a 20 m firn core. The first results of the traverse show that the surface mass balance at Dome B (2.28 g cm−2 year−1) is among the lowest in Antarctica. The firn temperature below the layer of annual variations is −58.1 ± 0.2°C. A very low value of heavy water stable isotope content (-58.2‰ for oxygen-18) was discovered at a distance of 170 km from Vostok Station. This work is the first step towards a comprehensive reconnaissance study of the Ridge B area aimed at locating the best site for future deep drilling for the oldest Antarctic ice.

scholarly journals Paleofluids and Recent fluids in the upper continental crust: Results from the German Continental Deep Drilling Program (KTB)

1997 ◽  
Vol 102 (B8) ◽  
pp. 18233-18254 ◽  
Author(s):  
P. Möller ◽  
S. M. Weise ◽  
E. Althaus ◽  
W. Bach ◽  
H. J. Behr ◽  
...  
Keyword(s):  
Continental Crust ◽  
Deep Drilling ◽  
Upper Continental Crust ◽  
Continental Deep Drilling
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