Dear Mr. Ebong,

it depends upon the type of deposit, its size and the mineralogy which can be oxidic, carbonatic, siliceous.. that you expect in the region under exploration.

I give you an overview of the Mn deposits in question which might help you find the most appropriate geophysical method:

(1)Magmatic  manganese deposits

(1)Sedimentary/volcanic-exhalative marine Mn deposits (SEDEX to VOLCEX)

(2)Volcano-sedimentary lacustrine

(3)Epithermal Mn in places with  gem quality rodochrosite

(4)Rhodonite skarn

(2)Structure-related manganese deposits

(1)Hydrothermal unconformity-related vein-type deposits

(2)Mixed-type unconformity-related vein-type deposits

(3)Rodochrosite veins

(3)Sedimentary manganese deposits

(1)Shallow marine Mn deposits with /without remobilization in subaerial regimes

(1)Clastic-hosted deposits

(2)Carbonate-hosted

(2)Mn deposits in black shales

(3)Mn nodules in deep-marine depositional environments (in parts endogeneous)

(4)Supergene manganiferous deposits

(1)Bog iron ores on siliciclastic bedrocks

(2)Manganiferous replacement deposits hosted by calcareous rocks

(4)Metamorphic manganese deposits (prevalently sedimentary protore)

(1)Manganiferous Banded Iron Formation

(2)Rhodonite gemstone deposits

If you  have selected one or two types you must also consider the physical signatures or contrast between ore body and host/country rocks.

Then you will be able to take a decision which type from geoelectrical, geomagnetic , gravimetric and seismic measures is most useful.

Best regards

H.G.Dill

Very exhaustive explanation has been given by Dr. Dill. As you know, Manganese is not found as a free element in nature and; it is often found in minerals in combination with iron. Because of this nature of Mn, I feel integration of Magnetic and Gravimetric surveys will be most useful in mapping the Manganese deposits. As rightly pointed out, there should be measurable physical contrast between the ore & the parent rock.

The best method is the spectral sensing techniques

If the terrain is clear of vegetation, they could use high resolution satellite data. As a first step ... with sample collection of the area, to verify the minerals and spectral responses of the mineralized surface.

The question is on the geophysical field investigations for manganese minerals, but somehow remote sensing technique has been advised. I am also not sure how Manganese minerals embedded in the parent rocks can be detected by remote sensing. I can only agree with air borne gravity or magnetic surveys for regional mapping, in the present context of geophysical technique.

I've tested the magnetic prospection. its give good negatives anomalies in dolomites host rock

@ Prof Dill,

Many thanks for the elaborate technical contribution to this topic. I sincerely appreciate.

Regards

Ebong

Technically, the question raised has been robustly addressed. I simply wish to add a few fundamentals that are often overlooked. Fundamentally, exploration geophysics is all about defining "appropriate physical property contrast", PPC. The success or otherwise of any exploration program depends on how well this concept has been addressed. The process of dealing with the concept can be tedoius as Dill has shown. It is therefore instructive to give background information, i.e intended geological environment, to get more concise answers. Generally, sedimentary environments provide greater anomaly opportunities with a wide variety of geophysical method options. Also, methods amenable to spectral decomposition can be more sensitive and diagnostic of specific mineralization. Exploration in Basement terrains are often better started off from above ground, geological/geophysical. Lastly, I wish to remind everyone of us that exploration geophysics is about geology and geophysics. As much as we may be champions with a  good command of one, we need more than a working knowledge of both to keep making the discovery of now rather subtle deposits in order yo keep the civilization going.

Thanks and Regards.

Salami

Many thanks Salami. The area is within the Basement complex and preliminary geologic mapping have been carried out and manganese mineralization were observed along vein structures.