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What is a great geologist?

Geology is an observational discipline (see What is a geologist?). But closely tied to the observational demands of the science, are the demands of curiosity. Curiosity is what drives the interest in observing. One of the greatest mistakes a geologist can make is the subjective viewing of the earth from a model-driven viewpoint. A model-driven approach is a kind of circular reasoning and ignores the value of evaluating multiple hypotheses. Models are useful. They give us a framework to gather observations (data) and build evidence to develop an interpretation(s). But models can blind us to important observations that maybe aren’t consistent with the model’s assumptions or somehow don’t fit the model. And since we have trouble seeing what we are not looking for, we must depend on curiosity to uncover the truth. And we hope that curiosity can help us to see something we don’t expect to see.

Geologists do work with conceptual models a lot — we must, given the infinity of unknowns about what happened in geological time. The trick is not to be fooled by them. I think of the quip that an engineer is one who thinks numbers are facts, whereas we geologists think that concepts are facts. Certainly, when working well, we show an ability to relate seemingly unrelated concepts (or facts!) and use them to create and bolster a story about the past — an interpretation. An ingenious example is the application of the observation of Saharan winds blowing dust westwards, far out into the Atlantic Ocean — then applying that model to western Canada Triassic rocks (Davies 1997).

According to Davies, the distribution of Quaternary dune-sand-derived turbidites off northwestern Africa, west-central Africa, eastern Brazil, and northwestern Australia has a relationship to offshore-directed winds transporting sand from coastal desert dune fields. The position of the present-day Saharan jet stream and related aeolian sediment transport is also shown in the figure opposite. Davies argued that similar processes, but in much shallower, lower-relief basin settings, may have occurred in the Lower Triassic Montney Formation of western Canada and in other Triassic units in that area.

While we use all the above talents in search of petroleum, how does a subsurface geologist work? I think dogged persistence and getting all the data possible go a long way towards successful prospecting — or ‘sleuthing’ as my friend and colleague Andy Vogan calls it. Gathering all the data possible within the time available is a basic prerequisite to doing your best sleuthing.


Another element we use in prospecting is the focus on ‘not just what is, but what might be’ (to quote Keith Williams, circa 1990). Our practice is limited by well control and perhaps seismic or other data. And certainly there is usually little data exactly where we want to drill. Thus we are always working with inferring ‘what might be’, between data points. That is the prize.


Davies, G R (1997). Aeolian sedimentation and bypass, Triassic of western Canada. Bulletin of Canadian Petroleum Geology 45 (4), 624–642.

The figure is from Davies (1997) and includes elements from: Sarnthein, M and L Diester-Haass (1977): Eolian sand turbidites. Journal of Sedimentary Petrology 47, 868–890. It is ©SEPM.

What is a geologist?