2007-03-04

geologist offers answers

The editor of the Alberta (Canada) Palaeontological Society's newsletter, and professional geologist in the Canadian oil and gas industry has graciously offered to field questions you might have in the areas of sedimentary rocks and palaeontology. Howard has spent much time hunting dinosaur fossils, but his primary interests are invertebrate fossils and microfossils (especially foraminifera).

Howard also offers MAGS greetings and the best of luck on the launching of this blog.

I have a few questions for you already Howard. I know that foraminifera are small, single-celled organisms, of which many look like little grains of rice. Can you tell us a bit more about foraminifera? How old are they--do most of them come from the eocene? Were they ocean dwellers or shallow sea dwellers? How and where do you hunt for this particular type of microfossil?

Blog users--if you have a question that you would like to ask about invertebrate fossils or microfossils, or if you have information in this area that you would like to share with us, please click the comment link below.

10 comments:

Howard Allen said...

I LOVE forams! Their biggest appeal to me is their stunning diversity of forms. The smallest ones are dust-particle sized, while the largest can be nearly the size of a frisbee (see Guiness Book of Records under "largest protozoan"). As you suggest, Mike, a more typical size is like a grain of sand.

You can think of foraminifera (forams for short) as "an amoeba with a shell". They are classified on the basis of the composition and structure of their shells. One group has shells made up of particles of silt or sand that are glued together by the foram animal. Some of these little guys can even select particular mineral types from the sediment to make their shells: magnetite, quartz, mica, diatom shells, sponge spicules, etc. How 'bout that for a single-celled organism! Another group makes its shells of opaque white calcite that looks for all the world like fine bone china. Another group uses transparent (sometimes colored) calcite that looks like glass.

The diversity of shell shapes is mind-boggling. One critter, Lagena, has a shell that looks like an elegant, fluted glass bottle or vase. Some look like miniature ammonites. Some look like bunches of grapes. Some look like strings of beads. Some look like bananas with ribs. Some form straight tubes. Some have multiple chambers inserted at precise angles. Some look like stars. Some look like rice grains. Some look like lentils. Some are attached to the sea-bottom like little trees. The variety is endless.

The geological range of forams is very long. The oldest ones are (I think) Ordovician, and they are very common in today's seas. They are almost exclusively marine (sea water), but some are tolerant of or prefer higher or lower salinities. They are also sensitive to water temperature, depth, energy level (calm water, pounding surf).

The only real limiting factor in collecting them is that you need a microscope, preferably a binocular dissecting scope, with magnification in the range of 10x to 50x. Many of these are available for a few hundred dollars or even less for used 'scopes.

You can find forams in all sorts of sediment. The easiest way is to simply grab a vial of sand from an ocean beach and look at it under the microscope. Tropical beaches, especially those near coral reefs (Florida, Caribbean, Mexico, South Pacific islands), tend to have more and larger forams than cooler water beaches, and muddier sediment tends to have more forams than coarser sand sediment. Bermuda's famous pink sand beaches are colored by billions of red and pink forams. Planktonic (floating) forams can be collected by dragging a very fine net behind a boat. I have obtained wonderfully rich collections of forams from gobs of mud brought up on a ship's anchor in the Arctic Ocean. I ask my friends (especially those who snorkel or scuba dive) to bring me back pill bottles or film cans or small zip-lock bags with sediment from their holidays. One person brought me a bottle of sediment from the Egyptian pyramid of Cheops that was full of fossil forams (Eocene). Turns out that the pyramids were built of limestone that is chock-full of big, lentil-shaped forams. I have rice-grain sized Pennsylvanian-age forams (fusulinids) weathered loose from limestone in Texas. I have collected similar, Permian-aged forams in the mountains of central British Columbia. Chalk and marl beds are a great source of foram fossils. I have seen beautiful forams in rock cuttings from deep in oil and gas wells I've worked on in Canada and Costa Rica.

Google "foraminifera" to find photos and more information on the web. The "bible" for foram enthusiasts is Part C (2 volumes) of the Treatise On Invertebrate Paleontology, which is available at bigger libraries (especially university libraries). Have fun!

Mike B said...

Thank you Howard. Your comment contains so much information, that I am going to pull the text out and create a new blog entry for it, to make it easier to find for future visitors to the blog.

I enjoy micromounts and microfossils very much. At one time, MAGS had a micromounters group that met monthly. The moderator is not with us anymore and no one stepped up to take the reigns. It would be nice to get that group started again. MAGS members--if you have an interest in micromounts, leave a comment or contact me directly and we cna check out the possibilities.

Mark H said...

I am interested in collecting and photographing microfossils and micromounts of minerals. I'm just starting and it would be nice to have a group with similar interests to share ideas and questions. That was a nice post by Howard Allen. I have enjoyed your site Mike. Very intresting topics.

Paulette said...

Howard - my husband and I are rockhounds and will be traveling from Vancouver Island to Sylvan Lake Alberta this spring. I haven't been able to find much info on collectible minerals in Alberta such as semi-precious stuff - other than coal, fossils (which I don't collect afraid I'll inadvertently carry away something important), gypsum crystals (somewhere), placer diamonds (somewhere) and placer gold - always fun to try. Any suggestions as to a field guide or relatively easy to get to places (likely rivers, streams etc)?

I appreciate your passion of forams - they are exquisite (I used to be a geology student in Texas and saw many slides of said creatures.)

Looks like a great blog and info center. Thanks

Paulette

adia said...

Hi.
I am a master student in petroleum geology. I am not very common with forams and this is my first time working with them. What is the best the way to determine them(foraminifera) in field?
I really need a good guide.

Thanks
Fauziah Hanis

Anonymous said...

Hi I was just wondering if anyone could tell me how much a geode could be worth! My mom has one that looks like there are three geodes fused together. It looks like 3 softballs fused together! And do we have to break them open for them to be worth something?

argon(one) said...

It's difficult to put a value on geodes. They can range in value from $5.00 to $50.00 for a normal-sized geode--tennis ball to bowling ball size [with some occasionally higher prices based on the number of minerals inside, rarity of the minerals found there and the quality of the crystals].

argon(one) said...

If you leave a comment here, please state it in English, since that is the only language I understand. Because I cannot determine the content of a comment left in a different language, I must delete it.

Nothing personal, I just want to make sure the comments here are family-friendly. Thank you for your understanding.

Jen Moss said...

Hello - I am relatively ignorant about rocks - but am tasked with putting together a list of commonly found rocks & minerals in the banff / canmore area for a project I'm doing. The project will live online, and is associated with the National Film board. If anyone can dash off a list of common rocks & minerals in this area (say, the top 20?) that would be wonderful!!! Meanwhile - I will keep looking. Thanks!

Jen.

TOR BAUGHER said...

I LOOOOOOVE ROCKS & MINERALS. I HAVE SINGLE HANDEDLY CARRIED ENOUGH QUARTZ & PET WOOD TO SURROUND OUR PROPERTY 2-3' WIDE!

ARE U STILL AVAILABLE FOR ADVICE? I'M IN ARIZONA-SOOO MANY BEAUTIFUL ROCKS & PLACES TO EXPLORE!

TORREY