Results 21 to 30 of about 392 (143)

Paleobiologia de Cloudina sp. (Ediacarano, Grupo Corumbá): implicações tafonômicas, taxonômicas e paleoecológicas [PDF]

, 2016
Cloudina foi o primeiro fóssil de um organismo biomineralizado encontrado no final do Ediacarano. Também figuram nesse período Corumbella, Namacalathus, Sinotubulites e Namapoikia entre a biota esquelética.
Kerber, Bruno Becker
openaire   +2 more sources

The evolution of reproduction in Ediacaran-Cambrian metazoans. [PDF]

Biol Rev Camb Philos Soc
ABSTRACT The evolution of reproductive style is a fundamental aspect of metazoan life history but has not been explored holistically through the Ediacaran–Cambrian rise of metazoans. Recent molecular clock analyses based on only unequivocal metazoan fossil calibrations suggest that Porifera were present by at least 590 million years ago (Ma), all major
Wood RA, Droser ML.
europepmc   +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

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

New and revised small shelly fossil record from the lower Cambrian of northern Iran

Papers in Palaeontology, Volume 7, Issue 4, Page 2141-2181, November 2021., 2021
Abstract Small shelly fossils (SSFs) are highly informative of the ‘Cambrian explosion’. Their palaeobiodiversity has been documented from lower Cambrian deposits worldwide but it remains elusive in areas such as Iran, despite this region occupying a critical position on the north‐western Gondwana margin during the early Cambrian. This new study of the
Léa Devaere, Dieter Korn, Abbas Ghaderi, Ulrich Struck, Alireza K. Bavandpur, Javier Álvaro   +5 more
wiley   +1 more source

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

Life history and autecology of an Ediacaran index fossil: Development and dispersal of Cloudina [PDF]

Gondwana Research, 2015
Abstract Cloudina is the best-known biomineralizing metazoan and a potential index fossil in the late Ediacaran Period, yet many aspects of its biology remain poorly understood. Previous reports have shown that Cloudina tubes grow from a basally closed funnel (or apical element), with occasional dichotomous branching.
Iván Cortijo, Yaoping Cai, Hong Hua, James D. Schiffbauer, Shuhai Xiao   +4 more
openaire   +1 more source

Cuando la vida anduvo errática: Un factor ambiental para la biomineralización de metazoos

Estudios Geologicos, 2019
La repentina aparición de metazoos biomineralizados en las facies calcáreas del Miembro de Pockenbank (Namibia) parece reflejar un rápido cambio en el estado redox, la concentración de calcio y la alcalinidad del océano.
A. J. Kaufman, L. Kriesfeld, P. Vickers-Rich, G. Narbonne   +3 more
doaj   +1 more source

New Facies Model and Carbon Isotope Stratigraphy for an Ediacaran Carbonate Platform From South America (Tamengo Formation—Corumbá Group, SW Brazil)

Frontiers in Earth Science, 2022
The Ediacaran is a period characterized by the diversification of early animals and extensive neritic carbonate deposits. These deposits are still not well understood in terms of facies and carbon isotope composition (δ13C). In this study we focus on the
Maria E. A. F. Ramos, Martino Giorgioni, Detlef H. G. Walde, Dermeval A. do Carmo, Gabriella Fazio, Lucieth C. Vieira, Matheus Denezine, Roberto V. Santos, Rodrigo R. Adôrno, Rodrigo R. Adôrno, Lucas Lage Guida   +10 more
doaj   +1 more source