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Geology topics

D. A. Chapin

Publications and source records attributed to D. A. Chapin.

3 recordsLinked to original sources

General philosophy 4

I offer these statements about the interpretation process: A contractor's job often consists of enhancing potential-field data to make them as interpretable as possible (by either the contractor or the client). In getting data ready for interpretation, I like to confine the work to “atural processes” and avoid arbitrary processes. I see too many people abusing the facilities available in commercial software packages and applying polygonal fits of the third, fourth, fifth, seventh, ninth order and calculating residuals until something strikes a chord, and then off they go and interpret the results. Alternatively, all too many people apply arbitrary frequency-domain filters chosen to pretty up the data without a lot of thought about the consequence. Then you no longer have a potential field.

Book chapter

General philosophy 3: Concerning modeling

The trend toward modeling is a healthy change from the days when “prospects” were located solely on the basis of closures on residual maps of mysterious and sometimes secret origin. Although residual maps are valuable for helping us notice unusual relationships, the business of exploration has become less tolerant of anything that raises more questions than it answers. A flurry of residual maps is a pretty good example of such a thing. Once an appealing target is noticed in a residual, its geologic origin ought to be questioned and justified in relation to the basic, measured data.

Book chapter

General philosophy 5: Concerning nonuniqueness

There are models we might like to accept that just dont fit gravity, magnetic, or electrical data. This benefit of modeling is important. It forces the interpreter to prove that an interpretation is possible, and it eliminates impossible models even seismic models. A simple depth estimate may be all the model one needs to eliminate an idea. Other times, we need a careful and detailed model to help us understand what’s possible and unambiguously impossible.

Book chapter