Limestone Classification for Dummies - The Freelance Files MMLXXXII

coral framestone

When a staffer ran across today's DotD nominee while surfing one of the new niche sites WiseGEEK has invented, she shuddered... not because the content was so bad (although it was), but because the topic meant she'd have to have a talk with the Antisocial Network's chief geologist. That's because some clueless freelancing "creative writing" or "communications" graduate decided she knew enough about carbonate sedimentology to answer the eternal question, "What is Boundstone?" (now living at niche site AllThingsNature.org). According to our geologist, however, Angela Brady was sadly mistaken...

We'll get the real definition out of the way first: Boundstone is the name of a type of limestone in Dunham's carbonate classification system. Essential to the definition is that the rock is in situ, or lithified where it was formed, and that it was created through organic growth. A classic example is (no surprise here) a coral reef.

Brady hemmed and hawed all around that definition, along the way showing her utter ignorance of her topic through some of the more... bizarre things she wrote. take, for instance, her initial definition:

"Boundstone is an indigenous deposit of limestone that was bound by algae, coral, or other unicellular organism when it was formed."

Uhhh, Angela? A coral is not a unicellular organism...

Once Angela coughed up that bit of misinformation, she plunged into the modified, expanded definition of a boundstone; in which she parroted large chunks of text that she didn't understand. Her polly-wanna-cracker version of carbonate classification generated some rather odd statements, including (but not limited to),

1. "Stromatolites, which are fossilized mounds of layered algal mat and sediment, are the most common form of bindstone." – Well, yes, stromatolites are fossil algal mats, but they aren't usually mounds. Our geologist is familiar with thin stromatolitic limestone layers that cover tens or hundreds of square miles. The mounds she cites are the famous Shark Bay, Australia, mounds; we guess.
2. "algae... holds together layers of mud and calcite..." – You meant calcareous mud, right, Angie?
3. "Framestone is distinguished by a rigid framework of fossilized organic matter, usually deep-water sponges..." – Sponges by themselves are unlikely to form a framestone, since their skeletons are quite fragile and break into fragments called spicules. The Porifera may be a component of framestone, but by themselves? Relatively unlikely.
4. "Most bindstone deposits are oriented vertically as opposed to horizontally, due to the layering manner in which they form." – Clearly, Brady did not understand what her reference said; as a consequence we can't understand this at all.

There was, of course, more; but that ought to be enough to convince even the most jaded carbonate petrologist that Brady is well-deserving of the singular honor of being named our Dumbass of the Day. Wear it well, Angie.

SI - PETROLOGY