anything more important to a geologist than an understanding of
the fundamentals of the science?
Peter Scholle, director and state geologist
with the New Mexico Bureau of Mines and Mineral Resources, who is
doing his part to educate other geologists on the basics of what
he calls a very important aspect of geology.
is the co-author of AAPG Memoir 77, A Color Guide to the Petrography
of Carbonate Rocks, designed to aid geologists' understanding
of the importance and value of petrography — what Scholle calls
one of those dying arts of fundamental geology.
Scholle wrote AAPG's Memoir 27 on the petrography of carbonate rock,
which is the evaluation of carbonate rock under the microscope.
It turned out to be one of AAPG's best selling books ever.
has progressed quite a bit in 25 years, and it was time to update
the book," he said.
in the making, Memoir 77 is not just an update of the classic Memoir
27, but a total re-do. All new digital photography has been used,
and the material covers significantly more ground.
Scholle thinks it's time to once again remind geologists of the
critical role techniques like petrography play in the science.
we do a very good job of dealing with the sexy new things — the
frontier technologies like geophysics, logging, horizontal drilling
— that have seen exciting progress over the last few decades,"
he said. "I am certainly not belittling that effort, because those
are stupendous technologies that have revolutionized the business.
the same time I, and probably anybody over the age of 40, look back
with some nostalgia on the important tried-and-true techniques that
are getting lost in the process but still have a lot of value."
Me, Feel Me, Touch Me
of rocks can't be imaged seismically, nor run off on a log, Scholle
likes to point out. They can't be determined any other way but by
looking at rock chips.
learn a great deal from petrography — where to drill next or where
not to drill," he said. "Looking at rock samples under the microscope
can uncover details like the history of the rock in the subsurface,
changes that have taken place in the rock as it was buried or heated
up, as hydrocarbons migrated through it, as it was uplifted or as
fresh water came through.
are tools out there like petrography and paleontology that are no
longer sexy, and they are being outsourced — or worse, not done
at all," he said, "and that's a shame, because there really is information
to be gained that can be integrated with new techniques."
hopes the book will be a starting point of a much larger effort
to re-introduce petrography to younger geologists and once again
make it part of the overall scientific effort. There have been discussions
about an online digital version of the book as well as training
courses on petrography.
is getting more hectic all the time, and petrography is not like
other specialties where you can just grind up a rock, throw it in
a machine and have an answer pop out the other side," he said. "It
is painstaking, laborious work that requires experience like any
other art form."
it is something that must be taught.
people the old fashioned way, by looking through a microscope with
an instructor at hand, or you use newer technologies like digital
expert systems online or CD-ROM based training modules," he said.
"There obviously are things you can't do with just a book. Training
requires seeing things under the microscope, how special lighting
effects can help uncover even more information."
a training course is not an option, the same can be conveyed with
online or CD-ROM based videos.
efforts within the profession are even more critical today because
more and more colleges and universities are dropping petrography
and paleontology courses. Scholle said it is up to the profession
to fill in those holes in young geologists' education — and to
let schools know they are sending out people who are not fully trained.
in this expertise hasn't hit yet," he said. "There are still enough
people with experience that are out there as consultants.
"I do think
it is unfortunate, although understandable, that companies are outsourcing
this very specialized work," he added. "Petrography is so fundamental
that I feel companies should have people within their organization
who can do it.
just put a rock in a bag and send it to an outside company and expect
an analysis," he said, because a petrographer has to know what you
want to learn about the rock:
you want to know what the rock was originally?
you want to know what happened to it?
you want the origin of the porosity?
those questions a petrographer has to know how it fits with the
other things you know — you can't learn everything by just looking
down the microscope at a rock," he said. "Petrography needs to be
integrated with the seismic, well information and other data to
his own career, Scholle said his advice for young geologists is
much the same as his reasons for signing on to do an updated book
on the petrography of carbonate rocks:
there are techniques and technologies that are cool and new, you
can't overlook the fundamentals," he said.
more people are pursuing specialties — 'I want to become an isotope
geochemist and know everything there is to know about how to run
a mass spectrometer.' But do you know what you are shoving into
that mass spectrometer?
today still need to know how to go into the field and accurately
map, record or measure stratigraphic sections," he said. "Petrography
is part of that whole process.
starts with knowing what you are looking at and analyzing within