Electromagnetic measurements in the vicinity of the KTB drill site. Part I: The MV results across a 2-D array

1993 ◽  
Vol 37 (1) ◽  
pp. 83-102 ◽  
Author(s):  
Václav Červ ◽  
Josef Pek ◽  
Jana Pěčová ◽  
Oldřich Praus
Keyword(s):  
Electromagnetic Measurements ◽  
Drill Site

Electromagnetic measurements in the vicinity of the KTB drill site. Part II. Magnetotelluric results

1993 ◽  
Vol 37 (2) ◽  
pp. 168-188 ◽  
Author(s):  
Václav Červ ◽  
Josef Pek ◽  
Jana Pěčová ◽  
Oldřich Praus
Keyword(s):  
Electromagnetic Measurements ◽  
Drill Site

Tracing the SW border of the Svecofennian Domain in the Baltic Sea region: evidence from petrology and geochronology from a granodioritic migmatite

2021 ◽  
Author(s):  
Evgenia Salin ◽  
Jeremy Woodard ◽  
Krister Sundblad
Keyword(s):  
Baltic Sea ◽  
Short Distance ◽  
Sedimentary Cover ◽  
Crystalline Basement ◽  
Drill Core ◽  
The Baltic Sea ◽  
Baltic Sea Region ◽  
Drill Site ◽  
Southwestern Margin ◽  
The Baltic

AbstractGeological investigations of a part of the crystalline basement in the Baltic Sea have been performed on a drill core collected from the depth of 1092–1093 m beneath the Phanerozoic sedimentary cover offshore the Latvian/Lithuanian border. The sample was analyzed for geochemistry and dated with the SIMS U–Pb zircon method. Inherited zircon cores from this migmatized granodioritic orthogneiss have an age of 1854 ± 15 Ma. Its chemical composition and age are correlated with the oldest generation of granitoids of the Transscandinavian Igneous Belt (TIB), which occur along the southwestern margin of the Svecofennian Domain in the Fennoscandian Shield and beneath the Phanerozoic sedimentary cover on southern Gotland and in northwestern Lithuania. It is suggested that the southwestern border of the Svecofennian Domain is located at a short distance to the SW of the investigated drill site. The majority of the zircon population shows that migmatization occurred at 1812 ± 5 Ma, with possible evidence of disturbance during the Sveconorwegian orogeny.

Electromagnetic measurements on Martian soil analogs: Implications for MARSIS and SHARAD radars in detecting subsoil water

2007 ◽  
Vol 55 (1-2) ◽  
pp. 193-202 ◽  
Author(s):  
Annamaria Cereti ◽  
Giuliano Vannaroni ◽  
Davide Del Vento ◽  
Elena Pettinelli
Keyword(s):  
Subsoil Water ◽  
Martian Soil ◽  
Electromagnetic Measurements

On: “Effect of tropical weathering on electrical and electromagnetic measurements” by G. J. Palacky and K. Kadekaru (GEOPHYSICS, January 1979, p. 69–88).

Geophysics ◽  
1980 ◽  
Vol 45 (7) ◽  
pp. 1205-1208
Author(s):  
B. B. Bhattacharya ◽  
P. K. Hazra
Keyword(s):  
Host Rock ◽  
Vertical Electrical Soundings ◽  
Electromagnetic Measurements ◽  
Tropical Weathering ◽  
Electrical Soundings

In this paper, the authors showed a series of electromagnetic (EM) profiles (Figure 20, p. 86) obtained from the ground follow‐up using a slingram system with a frequency of 1600 Hz and coil separation of 120 m. Measurements along all the profiles (A to E) show considerable in‐phase and quadrature anomaly. The host rock in this case is amphibolite. The vertical electrical soundings over the amphibolite (Figure 16, p. 82) indicate that the weathered amphibolite has mean thickness and resistivity of 8.5 ± 2.1 m and 29.7 ± 6.5 Ω-m, respectively. It would, therefore, be reasonable to assume that the in‐phase and quadrature anomalies have been influenced due to the presence of conducting overburden, and the response of the target in such a situation can be altogether different compared to the anomaly of the target in the presence of an insulating or highly resistive overburden.

scholarly journals At what depth is the Eemian layer expected to be found at NEEM?

2008 ◽  
Vol 48 ◽  
pp. 100-102 ◽  
Author(s):  
Susanne L. Buchardt ◽  
Dorthe Dahl-Jensen
Keyword(s):  
Flow Model ◽  
Accumulation Rate ◽  
Ice Core ◽  
Monte Carlo Analysis ◽  
Interglacial Period ◽  
Ice Flow ◽  
North West ◽  
Flow Parameters ◽  
Drill Site ◽  
Radio Echo Sounding

AbstractNo continuous record from Greenland of the Eemian interglacial period (130–115 ka BP) currently exists. However, a new ice-core drill site has been suggested at 77.449˚ N, 51.056˚Win north-west Greenland (North Eemian or NEEM). Radio-echo sounding images and flow model investigations indicate that an undisturbed Eemian record may be obtained at NEEM. In this work, a two-dimensional ice flow model with time-dependent accumulation rate and ice thickness is used to estimate the location of the Eemian layer at the new drill site. The model is used to simulate the ice flow along the ice ridge leading to the drill site. Unknown flow parameters are found through a Monte Carlo analysis of the flow model constrained by observed isochrones in the ice. The results indicate that the Eemian layer is approximately 60m thick and that its base is located approximately 100m above bedrock.

scholarly journals Geoelectric and electromagnetic measurements within an organized archaeological framework: the Marzabotto example

1994 ◽  
Vol 37 (5 Sup.) ◽  
Author(s):  
E. Bozzo ◽  
S. Lombardo ◽  
F. Merlanti ◽  
M. Pavan
Keyword(s):  
General Pattern ◽  
Geophysical Prospecting ◽  
Urban Structures ◽  
Water Wells ◽  
Electromagnetic Measurements ◽  
Homogeneous Environment

Geophysical prospecting was Performed in the Etruscan settlement of Marzabotto, near Bologna (Italy), to find shallow anthropic structures within an almost homogeneous environment. This paper describes some results of the geoelectric and electromagnetic VLF methods used. Non-standard geoelectric devices, such as the tripotential, twin-probe and the Offset-Wermer methods, were applied. The set of results was compared to classical dipolar sections. The Offset-Wenner device was useful for detecting vertically striking structures. Conversely, the electromagnetic VLF techniques are not suitable for investigating structures with a negligible contrast of conductivity with the environment. Prospecting data generated a general pattern of anomalies and some were confirmed by excavation samples, showing walIs, floors, water wells and other remains of urban structures.

scholarly journals Brief Communication: New radar constraints support presence of ice older than 1.5 Ma at Little Dome C

2020 ◽  
Author(s):  
David A. Lilien ◽  
Daniel Steinhage ◽  
Drew Taylor ◽  
Frédéric Parrenin ◽  
Catherine Ritz ◽  
...  
Keyword(s):  
Flow Model ◽  
Ice Core ◽  
Austral Summer ◽  
Basal Region ◽  
Glacial Cycles ◽  
Ice Flow ◽  
Vhf Radar ◽  
New Instrument ◽  
Drill Site ◽  
Ice Core Record

Abstract. The area near Dome C, East Antarctica, is thought to be one of the most promising targets for recovering a continuous ice-core record spanning more than a million years. The European Beyond EPICA consortium has selected Little Dome C, an area ~35 km south-east of Concordia Station, to attempt to recover such a record. Here, we present the results of the final ice-penetrating radar survey used to refine the exact drill site. These data were acquired during the 2019–2020 Austral summer using a new, multi-channel high-resolution VHF radar operating in the frequency range of 170–230 MHz. This new instrument is able to detect reflections in the near-basal region, where previous surveys were unable to trace continuous horizons. The radar stratigraphy is used to transfer the timescale of the EPICA Dome C ice core (EDC) to the area of Little Dome C, using radar isochrones dating back past 600 ka. We use these data to derive the expected depth–age relationship through the ice column at the now-chosen drill site, termed BELDC. These new data indicate that the ice at BELDC is considerably older than that at EDC at the same depth, and that there is about 375 m of ice older than 600 ka at BELDC. Stratigraphy is well preserved to 2565 m, below which there is a basal unit with unknown properties. A simple ice flow model tuned to the isochrones suggests ages likely reach 1.5 Ma near 2525 m, ~40 m above the basal unit and ~240 m above the bed, with sufficient resolution (14±1 ka m−1) to resolve 41 ka glacial cycles.

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