Results 161 to 170 of about 75,647 (379)
An ubiquitous ~62 Myr periodic fluctuation superimposed on general trends in fossil biodiversity [PDF]
arXiv, 2010 A 62 Myr periodicity is superimposed on other longer-term trends in fossil biodiversity. This cycle can be discerned in marine data based on the Sepkoski compendium, the Paleobiology Database, and the Fossil Record 2. The signal also exists in changes in sea level/sediment, but is much weaker than in biodiversity itself.
arxiv
Contributions to Canadian paleontology
, 1969 Chaetetipora ellesmerensis new species and Sibiriolites sibiricus Sokolov are described from Judge Daly Promontory and M'Clintock Inlet. Both species are from rocks of Richmond (Ashgill) age.
openaire +1 more source
Geobiology, Volume 21, Issue 1, Page 28-43, January 2023., 2023 Abstract Manganese (Mn) oxidation in marine environments requires oxygen (O2) or other reactive oxygen species in the water column, and widespread Mn oxide deposition in ancient sedimentary rocks has long been used as a proxy for oxidation. The oxygenation of Earth's atmosphere and oceans across the Archean‐Proterozoic boundary are associated with ...
Sam C. Spinks +7 more
wiley +1 more source
Beltanelliformis brunsae Menner in Keller et al., 1974: an undoubted Ediacaran fossil from Neoproterozoic of Dobrogea (Romania) [PDF]
Geodiversitas, Museum National d'Histoire Naturelle Paris, 2018, 2019 Ediacaran fossils are now largely known in different parts of the world. However, some countries are poorly documented on these remains of a still enigmatic life. Thus, rare fossils from the Neoproterozoic Histria Formation of central Dobrogea (Romania) have been reported. Two specimens with discoid imprints are described here in detail and assigned to
arxiv
Geobiology, Volume 21, Issue 1, Page 102-118, January 2023., 2023 Abstract Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial membrane lipids that are frequently employed as paleoenvironmental proxies because of the strong empirical correlations between their relative abundances and environmental temperature and pH.
Toby A. Halamka +6 more
wiley +1 more source
Geobiology, Volume 21, Issue 1, Page 119-132, January 2023., 2023 Abstract Stable isotopes in mollusc shells, together with variable growth rates and other geochemical properties, can register different environmental clues, including seawater temperature, salinity and primary productivity. However, the strict biological control over the construction of biominerals exerted by many calcifying organisms can constrain ...
Arianna Mancuso +5 more
wiley +1 more source
Most Compact Parsimonious Trees [PDF]
arXiv, 2016 Construction of phylogenetic trees has traditionally focused on binary trees where all species appear on leaves, a problem for which numerous efficient solutions have been developed. Certain application domains though, such as viral evolution and transmission, paleontology, linguistics, and phylogenetic stemmatics, often require phylogeny inference ...
arxiv
A Middle and Late Devensian sequence from the northern part of Kents Cavern (Devon, UK)
Journal of Quaternary Science, EarlyView.Abstract 1920s/30s excavation of a Middle Devensian sequence in the northern part of Kents Cavern recovered important Late Middle and Early Upper Palaeolithic archaeological material, including Britain's oldest known Homo sapiens remains. Questions remain about this material, including how it came to be in the cave.
Rob Dinnis +11 more
wiley +1 more source
A review of microbial‐environmental interactions recorded in Proterozoic carbonate‐hosted chert
Geobiology, Volume 21, Issue 1, Page 3-27, January 2023., 2023 Abstract The record of life during the Proterozoic is preserved by several different lithologies, but two in particular are linked both spatially and temporally: chert and carbonate. These lithologies capture a snapshot of dominantly peritidal environments during the Proterozoic. Early diagenetic chert preserves some of the most exceptional Proterozoic
Kelsey R. Moore +5 more
wiley +1 more source