The secret of the town hall - a mystery is unraveled

Worm traces of the late Carboniferous / early Permian


A facebook discussion in the triangle Canada/USA - Brasil - Germany leaded to a solution of a paleontological problem (some pictures of the discussion disappeared in the meantime...):

Maria Angelica Muniz Frosi from Brasil sent me some pictures of worm traces - or what else? She wrote: "While I was working in the city hall I saw and wondered why certain slabs of slate that form the entrance pavement of the building had different standards from others... They looked like strange marks like traces of worms." Maria has good connection to the architect of the hall and so she could find out, that the location is Central Trombudo, Santa Catarina. And there are glacial layers with traces left by invertebrate animals that move on the bottom of a lake. Like Maria explains, belong these rocks to the Itararé Group of the Paraná Basin and are a striking record of the great glaciation that occurred from the lower Carboniferous to the lower Permian, between 360 and 270 million years ago, when all the southern portion of the former supercontinent Gondwana were covered by thick layers known as Karoo Glaciation. We don't know whether these traces have a special name.
Patrick R Gonsoulin-Getty: (USA)  Beautiful specimens! The first, in particular, resembles Helminthoidichnites.
Uwe M. Troppenz: Dhiego Cunha da Silva (Brasil): I'm studyng this area in my master thesis. The place is fully rich of ichnofossil.The worm like traces are know as Helminthoidichnites tenuis. There are a few papers about the ichnology of this place (I'll adress below).I suggest this round marks were made by dropstones that felt in the upper layer and deform the stratum below. .

Glad to Help. Best regards

Lima, J.H.D., Minter, N.J. and Netto, R.G. 2017: Insights from functional morphology and neoichnology for determining tracemakers: a case study of the reconstruction of an ancient glacial arthropod-dominated fauna. Lethaia 50, 576–590.
Lima, J.H.D., Netto, R.G., Corrêa, C.G. and Lavina, E.L.C. 2015: Ichnology of deglaciation deposits from the Upper Carboniferous Rio do Sul Formation (Itararé Group, Paraná Basin) at central-east Santa Catarina State (southern Brazil). Journal of South American Earth Sciences 63, 137–148.
Netto, R.G., Balistieri, P.R.M.N., Lavina, E.L.C. and Silveira, D.M. 2009: Ichnological signatures of shallow freshwater lakes in the glacial Itararé Group (Mafra Formation, Upper Carboniferous–Lower Permian of Paraná Basin, S Brazil). Palaeogeography, Palaeoclimatology, Palaeoecology 272, 240–255.
Nogueira, M. dos S. and Netto, R.G. 2001a: A presença de Cruziana nos sedimentos da Formacao Rio do Sul (Grupo Itarare, Permo-Carbonifero da Bacia do Parana) na pedreira Itau-Itauna, Santa Catarina, Brasil. Acta geologica leopoldensia. Estudos tecnologicos 24, 387–396.
Nogueira, M. dos S. and Netto, R.G. 2001b: Icnofauna da Formacao Rio do Sul (Grupo Itarare, Permiano da Bacia do Parana) na pedreira Itau-Itauna, Santa Catarina, Brasil. Acta geologica leopoldensia. Estudos tecnologicos 24, 397–406.
Maria Angelica Muniz Frosi (Brasil): Thank you!! Very much!!!
Michael Davidson (Canada):I will give you the drop stone in photo 4. I am just puzzled about how there were worms crawling around under the ice of the Karoo Glaciation. Having said that, the ocean under Antarctica's floating ice is recognized as a biologically busy place.
Michael Davidson:The references above suggest the tracks were formed during the deglaciation period.
Maria Angelica Muniz Frosi Exact! The hypothesis of Dhiego and other paleontologists who studied this formation is that the marks that look like droplets were formed by rocks that sank in the process of melting!

Eldon Grupp: The small round crater-like holes on the first slab at the upper left are fossil raindrops! It rained the day this slab was preserved more than a quarter of a billion years ago!
Dhiego Cunha da Silva: In the first place i thought were rain drops too. But I was not able to find a good bibliography, in this case, do you have any recomendation?
Eldon Grupp: Dhiego Cunha da Silva: I was the one who suggested the litte craters were fossil raindrops. Here are bibliographic sources: - -

Fossil traces found in Sentinela do Sul (Rio Grande do Sul - Brasil)

According to researchers traces found in tiles were made about 300 million years ago
Who arrives in the building of the Sentinela do Sul City Hall and walks under the floor that gives access to the municipal body can not imagine that it treads on the tiles with traces fossils of more than 300 million years. The tiles made from slate slabs acquired over 20 years old come from the municipality of Trombudo Central, a municipality in the state of Santa Catarina.
This discovery of the vestiges was made by the public servant Maria Angelica Muniz Frosi, who at the time when she worked in the City Hall perceived different patterns in the tiles of access to the public building. The desire to know what would have shaped such grooves made her search for the origin of the stones.
With the help of the Internet she began a real scientific mobilization to discover the origin of these traits and already in the first contact Maria talked with the geologist Dhiego Cunha da Silva, who affirmed that these representations are known like "icnofósseis", common in the plates of slates taken from SC quarries.
According to the geologist, the municipality is the focus of several studies that seek to preserve the action of several animals that lived millions of years ago. "Unlike the body fossils that are commonly known, like the classic bones of dinosaurs and other vertebrates, the icnofósseis do not have remains of animals or plants, but they register the behavior of these organisms. These representations can be found in the form of burrows, footprints, traces of invertebrates (earthworm tubes, worm traps or larvae), urine marks and even fossilized feces," the geologist explained.
Maria's research crossed continents and arrived in Europe through the German paleontologist Uwe M. Troppenz, a scholar and author of a paleontology book, who does research and virtual forums on similar records found around the world. According to Uwe, the record may belong to invertebrate animals that were at the bottom of a lake in the glacial period. "There are glacial layers with vestiges left by invertebrate animals that move in the bottom of a lake," said the German during a debate promoted via Facebook. For the researchers the traits were left in the period of melting.

Discovery is to be taken to students

Maria Angelica's research should become a student project in the coming months. According to her, the idea is that students can know through research in the field, or even within the classroom, traces of animals that have inhabited our state in past ages. "The idea is to encourage young people to research and discover new cultural horizons. Unfortunately our region does not encourage such research on the beings who lived here millions of years ago, "Maria pointed out.
The project will depend on the support of the Municipal Government through the Municipal Education Department to be put into practice.