Tag Archive for 'Proterozoic'

Eukaryotic life appears to have flourished surprisingly late in the history of Earth. This view is based on the low diversity of diagnostic eukaryotic fossils in marine sediments of mid-Proterozoic age (around 1.6 billion to 800 million years ago) and an absence of steranes, the molecular fossils of eukaryotic membrane sterols. This scarcity of eukaryotic remains is difficult to reconcile with molecular clocks that suggest that LECA had already emerged between around 1.2 and more than 1.8 billion years ago. LECA, in turn, must have been preceded by stem-group eukaryotic forms by several hundred million years. Brocks et al. report the discovery of abundant protosteroids in sedimentary rocks of mid-Proterozoic age. Image credit: Arek Socha.

Molecular Remains of Ancient Complex Life Found in 1.6-Billion-Year-Old Rocks

Jun 8, 2023 by Enrico de Lazaro

Paleontologists have detected abundant protosteroids — traces of ancient life forms — in 1.6-billion-year-old sedimentary rocks that had formed...

Life may have begun shortly after Earth formed 4.54 billion years ago. Image credit: Hadeano.

Permanent Oxygenation of Earth’s Atmosphere Occurred Later than Previously Thought

Apr 6, 2021 by News Staff

Oxygen levels fluctuated dramatically for about 200 million years after the start of the Great Oxidation Event, with permanent atmospheric oxygenation...

Microphotograph of Ourasphaira giraldae. Image credit: Loron et al, doi: 10.1038/s41586-019-1217-0.

Paleontologists Find One-Billion-Year-Old Fossil Fungi in Canada

May 23, 2019 by Enrico de Lazaro

An international team of paleontologists has discovered 1,000- to 900-million-year-old microfossils of a fungus in estuarine shale of the Grassy Bay Formation...