Geophysics Analysis & Interpretation

ELECTROMAGNETIC

DELIVERABLES


Accurate Gridding
To achieve the high resolution mapping that we produce, traditional commercially available gridding techniques (Least square, linear, nearest neighbour, or kriging, etc) do not suffice. Our proprietary techniques have the ability to emphasize very small, local vs regional anomalies. 


Conductor strength and depth
We map the the strong and week conductive zones (conductors) which may not be clearly visible in dB/dt data. We then proceed with the production of a number of maps amplifying each specific conductor on its own.


Advanced EM mapping
TerraNotes and its partners have researched and developed a number of EM analyses that go much beyond the standard processing  techniques used by contractors and airborne companies.  

An example of such innovative imaging technique follows:

The left panel shows a standard VTEM processing map of the rough distribution of conductors.

The maps on the right is a zoom of the upper right corner of the VTEM map and displays the finished product provided by TerraNotes. Notice that the map highlights the dominant variations in the Tau grid, enhancing the broad units and cross-unit discontinuities -- a large conductive body will have a large Tau and thus the signal will decay slowly while a small poor conductor will have a small Tau and thus decay quickly).

The processing can map edges, ridges or valleys (such as central lows). This product shows the details of the trends, texture, complexity, locations of discontinuities and changes in conductor form.

We can also show various scales of the conductors identified.





















Geology of the survey area consists of Neoproterozoic siliceous turbidite & passive margin sequences; with Cambrian Mafic Intrusives and Volcanics



Cross Sections of the Conductors

We also provide cross sections of conductors in 3D that can be rendered in a movie animation showing lateral changes in the conductor attributes. Known or modeled geological features can be added to same animation to better understand the relationship between the conductor zone and the geology. 



                                                                   



























Inversions and Modeling
We produce a number of visualization of the conductors in 3D and slices.They are used for example to compare the near surface conductors from the E-W and vertical components. This can show discontinuities but can also be used to assess dip and attitude at depth. 
We also show conductors from Bz/dt field with a technology that is sensitive to near-surface and weak conductors; and from Bz field, a technology which is sensitive to deep and strong conductors. 
Consistency among the models is useful to assess more precisely the conductors' attributes at various depths.


Integration

​​We integrate multiple types of datasets (geophysics, geology, drill holes analyses, and geochemical datasets). 
We produce maps that compare and combine the Electromagnetic results with magnetic or gravity features and with other geophysical and geological data to assist in the interpretation stage. 


EM-SEISMIC RAPID SURVEYS
INNOVATIVE survey technique combining EM and Seismic surveys. This is a portable rapid delivery surveys that produce data we use for modelling and interpretation of conductive zones, basement, horizons, unconformity, faults and geobodies.


NEW AIRBORNE ELECTROMAGNETIC SURVEY CONFIGURATION
A new type of airborne survey configuration and equipment combines the best of both world: mapping both deep and near-surface conductors at the same time. This is one of the most powerful and accurate time domain configuration on the market at the moment.

The unique transmitter waveform includes a high-powered pulse for deeper exploration and a fast turn-off pulse to explore the near-surface, therefore increasing the bandwidth. 

The high power half-sine pulse ensures good depth of penetration and the low power square pulse allows a fast turn off and earlier off-time measurement as well to provide higher frequency information, thus enabling higher resolution.
The spectrum of the dual pulse (a half-sine and a square pulse) clearly demonstrates increased power in the higher frequency range (> ~ 2.3 kHz) than that of a single half-sine used by other airborne survey companies.

 
The following is an example of the combination of the 3 elements of this type of airborne EM survey:



Shallow penetration over

conductive overburden





Deep penetration




Combination of the

shallow and deep





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