Quartz arenites and wackes with intercalations of silty shales of the Ociesêki Formation were analysed in small outcrops and one core. The succession contains about forty-three ichnogenera and seventy-four ichnospecies, among which thirty-three ichnogenera and fifty-three ichnospecies are described by present author. The formation belongs to the Schmidtiellus-Holmia Superzone and to the Protolenus-Issafeniella Zone. Most strata are totally bioturbated. The diverse and numerous trace fossils represent the Cruziana ichnofacies in the lower part of the formation and the Skolithos ichnofacies in the upper part. A few possibly new ichnospecies of different ichnogenera have been described in open nomenclature. Sedimentary structures and trace fossil assemblages indicate that the older part of this formation was deposited on the upper offshore to lower shoreface, while its younger part was deposited on the lower to middle shoreface, where storm episodes were the main factor controlling sedimentation and the activity of benthos. The trace fossil associations studied are similar to those from the lower Cambrian in many places around the world. The ichnoassociations from the Polish part of the East European Platform and from Sweden, which represent the Baltica palaeocontinent, display the closest similarity.
A new ichnogenus and ichnospecies, Spirolites radwanskii, is a spiral boring recognized in large limestone clasts deposited in a Miocene cliff-foot ramp. It is characterized by a semi-circular or inverted Ω-shaped cross section, gradually increasing width, gradual entrenching in the rock from the narrower side, consistent coiling direction, steep margin from the wider side, two-order annuli, and occasional truncation of the narrower side by the wider part. It is interpreted as a boring of vermetid gastropods, similar to the recent Dendropoma. Spirolites co-occurs with the bivalve borings Gastrochaenolites, mostly G. torpedo, sponge borings Entobia, and the spionid polychaete boring Caulostrepsis, which are typical of the Entobia ichnofacies. Spirolites was produced in very shallow, clean and warm sea waters.
Two Upper Devonian to Lower Carboniferous sections, namely the Bulongguoer and Haer (Gennaren area) in the Junggar Basin, Central Asian Orogenic Belt, in northwestern China were examined with regard to ichnology and palynology. The deposits of the Hongguleleng Formation and Namu Member of the Heishantou Formation, respectively, are mostly unbioturbated or poorly bioturbated, with poorly diversified trace fossils, which indicate unfavourable conditions for the burrowing benthic community during the Late Devonian and Early Carboniferous. The main factor governing the growth of the bioturbating population was the rapid sedimentation of fine‐grained, volcanic material documented as tempestites, which buried the benthic fauna. In the Bulongguoer section, the presence of miospores Teichertospora torquata and Grandispora gracilis enabled identification of the broad Teichertospora torquata‐Grandispora gracilis Miospore Zone from the transitional Frasnian/Famennian interval. More accurate identification of palynostratigraphical levels (DE and CZ Miospore zones) is only tentative. On the basis of palynofacies analysis, samples from the lower Bulongguoer section indicate deposition in more proximal conditions, whereas samples from the top of the section indicate deposition in a more distal environment. In the Haer section, only a general biostratigraphic indication for the Tournaisian was possible, owing to poor preservation of organic matter.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.