Snuffboxes! Team Dorset has a project

June 8th, 2016

1 Snuffbox colection BBSherborne, England — Cassidy Jester (’17) now has a Senior Independent Study project: Origin and paleoecology of ferruginous oncoids (“snuffboxes”) from the Middle Jurassic (Bajocian) of southern England and northern France. (We’re not going to France; I have specimens I collected 20 years ago there.) Pictured above is a nice collection of these snuffboxes on the Dorset coast near Burton Bradstock. More on them below. Today Tim Palmer, Cassidy and I had a great time starting our data collection.

2 Whicher museumThe first thing we did this morning, though, was visit the astounding fossil collection of John Whicher, one of our new citizen scientist friends. He has a spectacular collection of exquisite fossils, most from the Inferior Oolite and all meticulously curated. His preparations are amazing, especially when you know what a fossil looks like when first collected.

3 Tim Cassidy Whicher museumTim and Cassidy are here admiring some of the Inferior Oolite ammonites in John’s display cases. Each specimen is numbered and has full locality and stratigraphic context.

4 Whicher workshopJohn has a workshop that would be the envy of any university, along with storage for those specimens awaiting his patient preservation. Here we see our other new friend Bob Chandler cutting a rock for us. Bob has his own equal collection. These indefatigable amateurs are making extraordinary contributions to science.

5 Burton cliff fallAt noon we started our own work along the coast at Burton Bradstock, Dorset. We depended upon cliff falls like this one where the rocks of the Inferior Oolite at the top of the cliff crashed to the beach below.

6 Burton Bradstock large block 060816This gorgeous block is an example of the snuffbox bed fallen into our hands on the Burton Bradstock beach. The long part of the measuring stick is one meter. We are looking at the base of the snuffbox-bearing unit, so the block is upside-down.

7 Cassidy working 060816Cassidy is here studying that above block, with the English Channel in the background and brilliant sunlight.

8 Snuffbox bored shell nucleusThis is one of the snuffboxes with a shell fragment as a nucleus. The shell has many borings that were excavated before it started accumulating the layers of iron oxides.

9 snuffboxes horns ooidsThe snuffboxes have all sorts of details, from the compositions of the nuclei, the structure of the cortices, the fossils found encrusting them, and their overall shapes. Many have “horns” in cross-section like the two above. Note also the iron ooids (rusty red dots) between the snuffboxes. Their origin is another mystery.

10 Cerne Abbey 585We ended the day with a visit to the ruins of Cerne Abbey in Cerne Abbas, which was founded in 987. The remaining buildings are considerably later but still incorporate remnants of the old. This is now a romantic ruin on a small estate.

11 Cerne Abbey signTomorrow we continue to study the snuffboxes in other localities. We hope again to avoid the rains that have affected much of the country this week.

Reference:

Palmer, T.J. & Wilson, M.A. 1990. Growth of ferruginous oncoliths in the Bajocian (Middle Jurassic) of Europe. Terra Nova 2: 142-147.

 

 

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