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This blog must be starting to feel neglected. This weekend, as with so many recent weekends, I am working hard to catch up with various tasks, many of them self-imposed. I am working on a paleontology/sedimentology project with two other people, a study of a small carbonate buildup in North Alabama, which is more than 300 million years old. One of us, not me, plans to point count a large number of thin sections. Point counting is when you use a grid to randomly select points on a surface. At each place where the lines cross you identify what's there, and the result is a tabulation indicating which things are common and which others are less common or absent. Well, Doug can't count points unless he knows what he's looking at. We have been working on a dictionary, so to speak, of what he might find. One of the fossils in this rock is a microscopic alga (?). There may be several different species represented, and I have spent the last few days measuring, counting, and examining specimens of this critter so that we can define what we should call these little guys when they show up in the crosshairs. I think it's a lot of fun to figure this stuff out, but the early stages, lots and lots of measuring and counting, require loud rock music so that I can stay focused. Bands like Mott the Hoople and the Velvet Underground are particularly useful for this purpose. I will show you guys some pictures later, in case you are interested, once I figure out what's going on.

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Composite photograph of a microconchid, seen under a microscope. They look like tiny snails, but are distant relatives. This one preserves multiple wall layers, but only part of the coiled tube is preserved. The originally hollow tube is filled with coarse calcite crystals.Mississippian, Alabama, scale is 0.2 millimeters.

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Last night I posted a high-magnification photo of part of this microconchid and the material that encrusted it (upper left). This one shows a cross-section of the entire critter, in all of its spiny glory. (The "spines" are actually ridges.) This is an encrusting organism, and you can see the dark layer at the bottom on which it grew (small white arrow).

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Complex microbial crust on microconch (bottom), Mississippian, North Alabama.

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Single-celled foraminiferan (arrow; shelled amoeba) in shelter void (small light area in lower center) within microcrystalline microbial coating (brown) on rugose coral (upper right). Growth of foram in this void indicates it was connected in the third dimension to open sea water at the time. Coral-microbial mound, thin-section photomicrograph, Mississippian, North Alabama.

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Tiny spiny sphere (center), a microfossil of some kind [algal spore?] and not the first of these I've seen from this location, in microbial mound [like a reef, but lacking a rigid skeletal framework], Mississippian, North Alabama, field of view 1 mm wide, thin-section photomicrograph.

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Microconch (cross-section showing 6 chambers) encrusting substrate (S) of microbial mudstone that coated rugose coral (out of sight to the left. Mississippian, North Alabama, in coral-microbial mound.

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 Cross-section through microconchid embedded in microbial mound, genus and species not yet determined. Thin-section photomicrograph, field of view 1 mm wide, Mississippian of North Alabama.

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Brown microbial lime boundstone containing diverse skeletal elements (upper right) adjacent to poorly sorted lime sand with calcite cement (lower left). Mississippian mound, North Alabame, 2.5 mm field of view. Pale colors of calcite crystals result from cross-polarized light. Sandstone contains crinoid fragments, chunks of boundstone, and many other kinds of particles, and fills a small void that was left open as the mound grew.

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 Mysterious spiky tube in Mississippian mound, North Alabama. We don't yet know what it is. Scale=0.2 mm.

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Thin-section photomicrograph of a small part of a coral-microbial mound. Loaf-shaped cells of the problematic organism Aphralysia capriori. Colonized by small undentified organism (white arrow). A. capriori cells are connected via openings in their microcrystalline walls (black arrow). Mississippian, North Alabama.

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I finally made it up to my office on Sunday and I have the print copies of Dreams and Nightmares 116. I will get subscriber and contributor copies in the mail as soon as possible. I also took about 30 photographs of very tiny fossils.

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Coral (lower right) encrusted by bryozoan (middle) in turn overgrown by microbial mud (dark layer) under an open void (now filled with calcite crystals (white, upper left). Mississippian, North Alabama, imaged area 2.5 mm wide.

 

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 Microbial boundstone with micropelletal cement (center), fenestral voids (left and right), and echinoid spine (in cross section, dead center). Mississippian, North Alabama, 2.5 mm wide.

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 Encrusting algae partly filled with micropelletal cement (center of image) on another algal structure (left), Mississippian, North Alabama, thin section photomicrograph, 2.5 mm wide.

 

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A new mound-building fossil (micro-alga?) from Alabama, Journal of Paleontology:

DOI: https://doi.org/10.1017/jpa.2019.103

These critters had relatives across the southeastern U.S. and western Europe, which were pretty close together 300+ million years ago, when they were living.

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Calcimicrobes, We Call Them

They look like a mound of slugs,

Huddled together for warmth,

But they weren't slugs at all,

Living in a salty sea;

What they were, no one knows.

He spends all his time in the lab now,

Looking through the tube

At things that died about

300 million years ago.

These are films of crystals engulfing other crystals,

But once they hung down from a roof

in a living reef,

They reproduced, their children found new homes

And they had children,

Not like his own children;

They were unknowing and unknown,

Spreading across what is now Alabama,

Cementing together the floor of an ancient sea,

A reef without corals,

Dead, no graves to visit,

Except these rocks,

Here, and in Belgium,

In Ireland, in Spain,

And god knows where else,

Doing their bit to hold things together.

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Two fenestrate bryozoans in bryozoan bafflestone (partly dolomitized) forming the uppermost part of a small mound near Haletown Tennessee, Mississippian Bangor Limestone, thin section photomicrograph, image 2.5 mm wide.

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A research project that started in 2016 has led to this paper being accepted by the Journal of Paleontology:

David C. Kopaska-Merkel, Douglas W. Haywick, and Richard Keyes, in press, A new mound-building biota from the lower Carboniferous of Alabama

We are already well into the next phase of the study.

A previous related publication:
.

Haywick, D.W., Kopaska-Merkel, D.C., and Keyes, R., 2016, Petrographic and faunal characteristics of Monteagle and Hartselle-equivalent strata in northeast Alabama, Gulf Coast Association of Geological Societies Trans. 66, p. 211-229.

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Floating reefs in Jupiter's thousand-mile-deep seas, hundreds of miles long and millions of years old, home to more species of organisms than have ever lived on earth. And this is where the kid wants to go for his 13th birthday. Why not someplace normal, like Disney World Ganymede?