Results 1 to 10 of about 340 (144)

Flexible and responsive growth strategy of the Ediacaran skeletal Cloudina from the Nama Group, Namibia [PDF]

Geology, 2017
Abstract The Ediacaran skeletal tubular putative metazoan Cloudina occurs globally in carbonate settings, which both provided lithified substrates and minimized the cost of skeletonization. Habitat and substrate preferences and the relationship of Cloudina to other metazoans have not been fully documented, so we know little as to its ...
Rachel Wood, Amelia Penny, Andrey Yu Zhuravlev   +2 more
exaly   +4 more sources

Reevaluación de la tafonomía de las asociaciones conservadas in situ de Cloudina en la Formación de Tagatiya Guazu, Grupo ediacárico de Itapucumi, Paraguay

Estudios Geologicos, 2019
La asociación fósil de la Formación de Tagatiya Guazu (Grupo ediacárico de Itapucumi, Paraguay) representa una oportunidad única para investigar los parámetros paleoecológicos y contribuir con información taxonómica sobre las asociaciones de Cloudina en ...
L. Inglez, L. V. Warren, J. Okubo, M. G. Simões   +3 more
doaj   +7 more sources

Inconsistencies in proposed annelid affinities of early biomineralized organism Cloudina (Ediacaran): structural and ontogenetic evidences [PDF]

Carnets De Geologie, 2012
Cloudina, un important fossile ediacarien, est considere comme l'un des pre-miers organismes biomineralises. Ses affinites biologiques n'ont pas encore ete entierement elucidees : des relations phylogenetiques avec les annelides et les cnidaires sont habituellement envisagees.
Olev Vinn, Michał Zatón
exaly   +3 more sources

The puzzle assembled: Ediacaran guide fossil Cloudina reveals an old proto-Gondwana seaway [PDF]

Geology, 2014
ABSTRACTDuring the Ediacaran the Clymene Ocean separated the Lau-rentia, Amazonia, and Rio Apa cratons from several landmasses to the west forming the proto-Gondwana supercontinent. However, no clear evidence about the existence of Ediacaran epeiric seas over those landmasses has been found.
Claudio Riccomini, M G Simões, Nicolas M Stríkis   +2 more
exaly   +5 more sources

The Ediacaran-Cambrian Radiation of Animals within the Villuercas-Ibores-Jara UNESCO Global Geopark, Spain [PDF]

Geoconservation Research, 2021
Across the Ediacaran to Cambrian transition, some 541 Ma, the Earth's biosphere changed from one dominated by microbial organisms to one where multicellular organisms, including animals, rose to importance. Within a few tens of millions of years into the
Iván Cortijo, Teodoro Palacios, Sören Jensen, José María Barrera   +3 more
doaj   +2 more sources

Microbialite Diversity and Ocean Redox Geochemistry of the Late Tonian Callison Lake Formation. [PDF]

Geobiology
ABSTRACT Microbialites provide a unique insight into ancient microbial processes and environments, but trends in the diversity of unlaminated microbialites remain poorly understood. The ca. 745 Ma Callison Lake Formation in the Yukon (northwest Canada) features a range of microbialites which are diverse at both the mesoscale and microscale.
Spruzen C, Wallace MW, Lechte MA, Hood AVS, O'Connell B, Halverson GP.   +5 more
europepmc   +2 more sources

Localized and Transient Oxygenation of Shallow Oceans of Southwestern Laurentia at the Ediacaran-Cambrian Boundary. [PDF]

Geobiology
ABSTRACT The Ediacaran–Cambrian boundary, which precedes one of the most significant biotic diversification events in Earth's history, is associated with a global negative carbon isotope excursion termed the BAsal Cambrian carbon isotope Excursion (BACE).
Chanchai W, Nelson LL, Smith EF, Hardisty DS, Lonsdale MC, Burke JE, Lau KV.   +6 more
europepmc   +2 more sources

Doushantuo-Pertatataka—Like Acritarchs From the Late Ediacaran Bocaina Formation (Corumbá Group, Brazil)

Frontiers in Earth Science, 2021
Acritarchs, a polyphyletic group of acid-resistant organic-walled microfossils, dominate the eukaryotic microfossil record in the Proterozoic (2500–541 Ma) yet exhibit significant reduction in diversity and size at the transition to the Phanerozoic (541 ...
L. Morais, L. Morais, T. R. Fairchild, B. T. Freitas, I. D. Rudnitzki, E. P. Silva, D. Lahr, A. C. Moreira, E. A. Abrahão Filho, J. M. Leme, R. I. F. Trindade   +10 more
doaj   +1 more source

Three‐dimensional reconstruction, taphonomic and petrological data suggest that the oldest record of bioturbation is a body fossil coquina

Papers in Palaeontology, Volume 9, Issue 6, November/December 2023., 2023
Abstract Fossil material assigned to Nenoxites from the late Ediacaran Khatyspyt Formation of Arctic Siberia (550–544 Ma) has been presented as evidence for bioturbation prior to the basal Cambrian boundary. However, that ichnological interpretation has been challenged, and descriptions of similar material from other global localities support a body ...
Christos Psarras, Philip C.J. Donoghue, Russell J. Garwood, Dmitriy V. Grazhdankin, Luke A. Parry, Vladimir I. Rogov, Alexander G. Liu   +6 more
wiley   +1 more source

Unmixing of Magnetic Hysteresis Loops Through a Modified Gamma‐Cauchy Exponential Model

Geochemistry, Geophysics, Geosystems, Volume 24, Issue 8, August 2023., 2023
Abstract Quantifying the contributions of distinct mineral populations in bulk magnetic experiments greatly enhances the analysis of environmental and rock magnetism studies. Here, we develop a new method of parametric unmixing of susceptibility components in hysteresis loops.
U. D. Bellon, R. I. F. Trindade, W. Williams   +2 more
wiley   +1 more source