High resolution aeromagnetic survey of Lake Superior

Eos ◽  
1991 ◽  
Vol 72 (8) ◽  
pp. 81-81 ◽  
Author(s):  
D. J. Teskey ◽  
M. D. Thomas ◽  
R. A. Gibb ◽  
S. D. Dods ◽  
R. P. Kucks ◽  
...  
Author(s):  
Thorkild M. Rasmussen

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article. Rasmussen, T. M. (1). Aeromagnetic survey in central West Greenland: project Aeromag 2001. Geology of Greenland Survey Bulletin, 191, 67-72. https://doi.org/10.34194/ggub.v191.5130 The series of government-funded geophysical surveys in Greenland was continued during the spring and summer of 2001 with a regional aeromagnetic survey north of Uummannaq, project Aeromag 2001 (Fig. 1). The survey added about 70 000 line kilometres of high-quality magnetic measurements to the existing database of modern airborne geophysical data from Greenland. This database includes both regional high-resolution aeromagnetic surveys and detailed surveys with combined electromagnetic and magnetic airborne measurements.


2007 ◽  
Vol 135 (12) ◽  
pp. 4202-4213 ◽  
Author(s):  
Yarice Rodriguez ◽  
David A. R. Kristovich ◽  
Mark R. Hjelmfelt

Abstract Premodification of the atmosphere by upwind lakes is known to influence lake-effect snowstorm intensity and locations over downwind lakes. This study highlights perhaps the most visible manifestation of the link between convection over two or more of the Great Lakes lake-to-lake (L2L) cloud bands. Emphasis is placed on L2L cloud bands observed in high-resolution satellite imagery on 2 December 2003. These L2L cloud bands developed over Lake Superior and were modified as they passed over Lakes Michigan and Erie and intervening land areas. This event is put into a longer-term context through documentation of the frequency with which lake-effect and, particularly, L2L cloud bands occurred over a 5-yr time period over different areas of the Great Lakes region.


Geophysics ◽  
1971 ◽  
Vol 36 (4) ◽  
pp. 695-716 ◽  
Author(s):  
B. K. Bhattacharyya

An automatic method has been developed for compilation of digital aeromagnetic data. This method has been applied to the data obtained during a high‐sensitivity aeromagnetic survey over an area in the Precambrian shield of northeastern Ontario in Canada. With this method, all points of intersection between traverse and base lines are determined automatically and adjusted within the limits of positional error for minimizing differences in magnetic values at the intersections. Then the data are corrected for diurnal variation and leveled to tie the magnetic measurements together. Next, the resulting total field values are contoured with a machine method at a scale of 1:25,000. For such a scale, the minimum contour interval that can be used in the present area is two gammas. However, because of the accuracy of the method of compilation, with a larger scale, it is possible to trace one‐gamma contours. The maps thus compiled have been compared with published aeromagnetic maps of data obtained with conventional flux‐gate and proton‐precession magnetometers. The new maps are vastly superior to the old ones for delineating trends, patterns, and fine features of available detailed geological maps. This superiority is mainly due to the excellent definition of small amplitude anomalies, some of only a few gammas in magnitude, on the high‐resolution magnetic maps.


2004 ◽  
Vol 41 (5) ◽  
pp. 603-618 ◽  
Author(s):  
Christine St-Laurent ◽  
Daniel Lebel ◽  
Denis Lavoie ◽  
Michel Malo ◽  
Camille St-Hilaire

In the vicinity of the Town of Gaspé, the relationships between the Silurian-Devonian sedimentary succession of the Gaspé Belt and the Humber and the Dunnage zones are complex. To unravel these relationships, we used high-resolution aeromagnetic data and regional gravimetric data coupled with field tectonostratigraphic information. The magnetic vertical derivative located several magnetic anomalies associated with near-surface features in the Silurian–Devonian cover sequence. In particular, a conglomerate with magnetic fragments that overlies the Late Silurian Salinic Unconformity is clearly recognizable. Large ovoid anomalies of significant intensity located in the Silurian–Devonian sedimentary cover area cannot be associated with any known geological feature. The interpretation of the high-pass and low-pass filtered aeromagnetic survey indicates that the ovoid anomalies originate below the Silurian–Devonian cover sequence. The most significant of the ovoid anomalies is associated with a gravimetric anomaly. It is proposed that these geophysical anomalies are probably associated with ultramafic and (or) volcanic rocks correlative in the subsurface with outcrops of the Cambrian–Ordovician lithologies of the Lady Step Complex and (or) the Shickshock Group.


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