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| Titel |
Interpretation of regional magnetic anomalies of the East - European Platform for spherical Earth |
| VerfasserIn |
M. Orliuk, A. Marchenko |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250030341
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| Zusammenfassung |
| Regional magnetic anomalies (RMA) are one of important information generators for
research of deep structure of the Earth’s crust and small scale forecasting of mineral deposits.
RMA were selected and interpreted first in the 2D variant by Krutikhovskaya Z.A. with
co-authors for the Ukrainian Shield (Krutikhovskaya at al., 1982). In future RMA it was
selected for territory of Ukraine and East - European platform (EEP) (Pashkevich I.K. et al.,
1990; Orlyuk M.I., 1999), and their interpretation is executed in a 3D variant (Orlyuk M.I.,
1999; Orlyuk M.I., 2000). First approaching location of sources RMA and values of the
magnetic susceptibility it was got as a result working out of small scale 3D magnetic
models of Ukrainian Shield, territory of Ukraine and East - European platform. Thus
interpretation was executed at the identical values of the magnetic field of Earth for large
territories.
An account of spherical of Earth is the new stage of interpretation of RMA. The sizes of
anomalies (tens kilometers in a crossing and hundreds kilometers by a slowness)
require the account of spherical. All of it needed development adequate ÎBa of
the mathematical, algorithmic and programmatic providing of interpretation of
RMA.
The mathematical providing and programmatic algorithmic complex was developed by
V.M.Kovalenko-Zavoysky and I.M.Ivashchenko (2006), which allows to calculate the vector
of magnetized sources of RMA for arbitrary correlation of the constituents vector
Ba.
Presence of values of the module induction of the geomagnetic field B, component of the
normal magnetic field of Earth B0, B0x, B0y, B0z on the epoch of calculation of anomaly
ÎBa and it ÎBax, ÎBay, ÎBaz- component is need for calculations. Quantitative
interpretation of RMA takes into account nonlinear character of the field ÎBa. Early during
interpretation of anomaly of ÎBa “substituted” the anomalies of vertical component of
ÎBaz, that led to the substantial errors during interpretation.
The specific of the interpretation of RMA in spherical coordinates are used geocentric and
local systems coordinates. The results of calculation are given in the geocentric system of
coordinates (latitude and longitude point of the field calculation - in degrees and
minutes).
This interpretation complex was used for interpretation of the RMA of the East-European
platform. Interpretation was taken to the calculation and interpolation component of the
normal geomagnetic field on a spherical surface and decision of direct task in spherical
coordinates.
A spatial location and intensity of anomalies is taken from digital map of the regional
magnetic field ÎBa.reg of the East - European platform and surrounding territories (Orlyuk,
2000).
The models of sources RMA were set a few spherical blocks, each of which was
characterized homogeneous magnetic susceptibility and different values of the normal
geomagnetic field.
According to calculations magnetic susceptibility of sources of north part of EEP changes
from Ï =0,002 Si to Ï = 0, 0058 Si (at the value of the normal geomagnetic field B0
=52 500- 54 500 nT), and from Ï=0,001 Si to Ï= 0,006 Si for south part of EEP
(at B0 =49 500- of 52 500 nT). So, the methodical features interpretation of the
geomagnetic field are considered taking into account spherical of Earth. The first variant of |
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