ARE WE MISSING SOMETHING?

I recently had an interesting and more than mildly concerning discussion with a colleague on LinkedIn. I market myself as a structural geologist and consider myself good at my craft. The conversation with Gharlied Abrahams highlighted extreme variation in opinion regarding the interpretation of geology. So, what was the discussion about and what sponsored it? The discussion was about structures in drill core, or it started that way. It was generated by some excellent photos that were posted by Anani Tebagwe .

The over-arching thesis of my colleague is that structures can’t be identified in photos. The implications of my colleague’s thesis is that logging of structures from core photos and, by implication, from any photos, is not possible. Within the discussion, the structures that my colleague indicated as being unrecognizable in photos include compositional layering, fractures, faults, folds, axial planes and fractures. So, just a few of the implications of this are that it nullifies any of the structural logging geologists have undertaken from core photos (including measurements from photos of oriented core), it voids examples in publications (LinkedIn posts, prospectuses, scientific papers, text books, company reports etc), and it renders useless that role of AI that has been trained to recognise structures in core. Obviously, this is just a short list.

I thought the thread of the conversation had too many implications for geology in general for it not to be shared, especially if these ideas are being promoted on a professional network such as LinkedIn. In fairness, I have tagged Mr Abrahams in this post. I have done this so that there is open discussion and so that Mr Abraham's points of view are not misconstrued.

The photo collage that started the conversation is shown here:

I ‘liked’ the post and then saw a comment by a colleague Mr Gharlied Abrahams. The comment, verbatim, was this ‘Structural geology? How so no structures here just a heterogeneous core!’. As the conversation between my colleague and I ‘progressed’, a number of assertions were made by my colleague that I simply did not, and do not, agree with, and I would like to share them, because:

·?????? if my colleague is correct, then the fundamentals of structural geology and use of oriented core have been challenged, and I think these ideas are alarming if they are being promoted

·?????? the work and expertise of many geologists and geological disciplines has been called into question and disregarded

·?????? selfishly, I’m trying to allay some of my concerns. I believe we have come a long way with regard to analysing core structurally, from real-time to subsequent virtual logging, and from identification of structures in the core shed and in photos through to their incorporation into models. I see the comments in the post thread as uninformed and flawed, but maybe I have missed something.

I’ll summarise my colleague's assertions below and preface them with some things I’d like to know. The things I’d like to know are:

1. if people agree with me that the photos from the original public LinkedIn post show recognizable structure populations, of if they think the images don’t show any structural features.
2. if the photos in this post do contain structures, do people think I have overly embellished the photos with the basic structures that I have labelled in the second photo below
3. if people have encountered similar ideas to those presented by colleague, and that I strongly disagree with

The basic assertions of my colleague can be summarized as follows:

• The photos shown do not contain structures and structures cannot be identified from photographs. This includes fundamental features such as compositional layering and the others that I believe I have correctly labelled. To quote my colleague ‘there is nothing that these images are showing that jumps out with 100% certainty that they are displaying any structures whatsoever’
• Drill core needs to be oriented in order to recognise structures. For me, this makes no sense, suggesting that structures only miraculously appear and/or can be identified if the core is oriented. Note, we are talking about recognition/designation of structures here, not whether they can be measured.
• Regional to microstructural information is required to identify structures in drill core or it is ‘simply pulling straws’.
• This comment verbatim ‘What I am getting from this is that you simply looked at a picture and made several conclusions based on..... ? If this was a crime scene and a photo of the scene was shown to a detective, odds are that he/she wouldn't have nearly enough evidence to put the criminal away. In the same way your statements are lacking all kinds of concrete evidence.... It's been brought to my attention that this is how structural geologists went about their findings back in the day, and senior folk are finding it difficult to step out of their comfort zones by adopting an individualistic integrated approach....'

For the reader’s information, the first part of the conversation is given below.

The rest of the discussion can be seen at https://www.dhirubhai.net/feed/update/urn:li:activity:7106491534920851457/.

CONVERSATION WITH MR GHARLIED ABRAHAMS – initial comments

Gharlied Abrahams

Structural geology? How so no structures here just a heterogeneous core!

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Brett Davis

Gharlied Abrahams I see faults, lithological layering, veins, open folds, fractures etc. All are structures and should be documented as such.

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Gharlied Abrahams

Brett Davis That's great ????. Not seeing any of those sorry!

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Brett Davis (genuinely surprised)

Gharlied Abrahams seriously?!

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Gharlied Abrahams

Looking at the core, there are a bunch of things that different geologist will likely interpret differently. We don't know the lithologies, mineral assembledges, ages of the various layers/lithologies and a list of other important geological information. If your statement went along the lines of e.g the core seems to display XYZ then there wouldn't be a factor of arrogance.... Leaving it for further geological investigation....

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Brett Davis

Gharlied - I have taken the time to label some of the basic structural geological features evident in the photos in the post. These are fundamental features that any geologist needs to know. You don't need to know the lithology in order to identify lithological layering. It's like seeing a car on the road - you might not know that make and model but you should know it is a car. Layering provides a marker that is separated to give evidence for fractures and faults. Deviations from planarity give fold geometries including an axial plane. Folds are geometries - you don't need to know the mineralogy of the marker units defining them in order to identify them as fold. Veins are sites of hydrothermal mineral deposition - we don't need to know the mineral assemblage to identify it as a vein. We don't need to know absolute ages of any of the features in order to define structures - just geometries and relative overprinting ages. None of your comments make sense in the context of the photo. There was no implied arrogance and I won't apologise if you want to feel that way.

Before you go to the comment thread at https://www.dhirubhai.net/feed/update/urn:li:activity:7106491534920851457/ it is interesting to note that the author of the original post agrees with my annotations. But please don’t let that detract from the content of the comment thread!