PETROGThe only tool for digital petrography

data collection, management, analysis, presentation and sharing

Core material is retrieved at great expense. It is needed both because we want to see for ourselves (i.e. ground-truth) that which otherwise we can only infer indirectly (by petrophysical logging, seismic survey, etc.) and because there are some things which can only be seen directly.

Petrographic analysis is generally the only time a geologist looks at the rock to determine its composition. If we are only going to look at the rock once, we must do it right first time.

Under the cross hair we see ‘booky’ kaolinite filling a grain mouldic pore created by the dissolution of plagioclase feldspar. In a traditional petrographic report the reader would see only an image and possibly some small data parameters. In Petrog the image is connected to the description and to the exact point on the slide - and this is true for every point described on the slide.

Looking down a microscope:

How much of this information would be captured by a petrographer using a 20-channel point counter?

20 channels means that everything that can be said about the entire slide has to be one of 20 different pre-determined categories.

If we have 5 different grains on the slide and 4 different clay overgrowths, that’s 20 already, and we haven’t begun to consider clay habit, let alone porosity, …..

PETROG provides the ability to describe each point in one of hundreds of millions of different ways with an average of only 3 - 4 clicks of the mouse, in a matter of a few seconds.

In this case: a point on this slide could be described as:

1st Click: Authigenic Kaolinite Group

2nd Click: Platy – Books3rd Click: Cementing

4th Click: Grain Mouldic porosity5th Click: Filling pore

6th Click: pore formed ‘from dissolution of’

7th Click: Plagioclase detrital mineral

So what did we see at the data point (everything else is not relevant in a sampling based procedure):Authigenic kaolinite with a ‘booky’ growth form filling a grain mouldic pore which was formed by the dissolution of plagioclase feldspar

So we now have 3 elements involved in a diagenetic sequence with their relationships recorded.

A sequence of 7 quick clicks gives us:

• Mineralogy of the data point under the cross hair• Morphological growth form(s) of the mineral• Relationship & habits of this mineral to the

adjacent rock elements• Sequence of diagenetic events at this point

…. and all data is immediately stored digitally and in a hierarchical form. This means that the petrographer can describe ALL of what s/he sees at the sampling point on the slide, not have to second-guess how the data will later be used and structure his limited data collection system to capture only those relevant data elements.

All data arranged hierarchically:

Because the data are stored hierarchically in the PETROG database, the petrographer is free to log and describe exactly what s/he sees, knowing that the analyst or any subsequent user can see more detail or a summary as the context requires.

For example, “Allophane” will be included in any report of Clay Minerals; the sum of all silicate materials will include Sheet Silicates, Double-Chain Silicates, etc.: the petrographer is not forced to describe the rock in terms which will be expected in the report.

The petrographer is more comfortable, looking at the monitor instead of changing eye focus repeatedly, so s/he can capture

MORE DATA FASTER!

…and once the data collection is complete, analysis is quick and simple, including all the tools one would expect, such as ternary plots

as both interactive exploratory or analytical tools on screen and high quality reporting tools for printing hard copy or creating digital displays.

…and analyses which make full use of the additional data collected, to estimate original mineralogy, analyse microporosity, compare with other available numerical data sources (such as core analysis and XRD) and many more interactive analyses or hard copy displays, which have hitherto not been possible in any repeatable, quantitative way.

PETROGThe only tool for digital petrography

data collection, management, analysis, presentation and sharing.

www.petrog.com