Angel Island, San Francisco Bay, is one of the most geologically interesting places, with pilllow basalts, blueschists and serpentinites and wackes. These rocks have been scraped from the subducting plate and represent remnants of a Jurassic oceanic crust, now completely tectonically mixed, in what is called mélange (mixture in French). The Franciscan mélange was formedContinuar lendo “PILLOW LAVAS, BLUESCHISTS AND OTHER ANCIENT OCEANIC ROCKS / LAVAS EM ALMOFADA, XISTOS AZUIS E OUTRAS ROCHAS OCEÂNICAS ANTIGAS”
Arquivos da categoria: Ancient Oceans
Microbes influence the formation of iron deposits and can be used in energy fuel cells / Micróbios influenciam na formação de depósitos de ferro e podem ser usados em células de geração de energia
Banded Iron Formations are characteristic iron-rich rocks. The deposition of these rocks occured in specific time intervals in Earth history, such as during the first Great Oxygenation Event (GOE) at ca. 2.4-2.2 billion years ago and after the Neoproterozoic Snowball Earth glaciations (Rapitan-type iron formations). A number of factors seem to have been interconnected inContinuar lendo “Microbes influence the formation of iron deposits and can be used in energy fuel cells / Micróbios influenciam na formação de depósitos de ferro e podem ser usados em células de geração de energia”
Stromatolites, the oldest living fossils, part 2: Lagoa Salgada, Rio de Janeiro, Brazil / Estromatólitos, os mais velhos fósseis vivos, parte 2: Lagoa Salgada
Another place where we can find recent stromatolites, Earth’s oldest living fossils (see last post for more info) is at Lagoa Salgada, Rio de Janeiro, Brazil. The pools are for salt evaporation and exploration. Thanks @samyrvq for the very cool pics! Outro local onde podemos encontrar estromatólitos recentes, os fósseis vivos mais antigos da TerraContinuar lendo “Stromatolites, the oldest living fossils, part 2: Lagoa Salgada, Rio de Janeiro, Brazil / Estromatólitos, os mais velhos fósseis vivos, parte 2: Lagoa Salgada”
Stromatolites, the oldest living fossils – part 1: Shark Bay, Australia / Estromatólitos, os mais velhos fósseis vivos, parte 1: Shark Bay
Stromatolites are the oldest known evidence of life, dating back to more than 3.5 billion years ago. They are formed by colonies of cyanobacteria that trap mostly calcareous sediments in column-shaped structures. Nowadays they only occur in places with high salinity where animals that mess up the ocean floor in search of food (the seagrazers)Continuar lendo “Stromatolites, the oldest living fossils – part 1: Shark Bay, Australia / Estromatólitos, os mais velhos fósseis vivos, parte 1: Shark Bay”
Project MOBILE 