Tonian island arc remnants in the northern Ribeira orogen of Western Gondwana: The Caxixe batholith (Espírito Santo, SE Brazil) – (Santiago et al. 2020)

Island arcs are magmatic arcs formed when oceanic tectonic plates slide below one another in subduction zone settings, just like in the present-day southwestern Pacific Ocean, as in Japan and Indonesia. Island arcs are important tectonic components to understand the evolution of the planet and consequently the continents and oceans that existed in the past.Continuar lendo “Tonian island arc remnants in the northern Ribeira orogen of Western Gondwana: The Caxixe batholith (Espírito Santo, SE Brazil) – (Santiago et al. 2020)”

Qual a relação entre biodiversidade e o ambiente tectônico? What is the relation between biodiversity and the geological setting?

The Ordovician radiation was one of the most significant diversifications of marine life and it coincides with a time of intense orogenic activity. The geographic distribution of 6576 appearances of Ordovician genera was investigated, in order to understand the relation among biodiversity and the geological context (foreland basins, transition zones, and carbonates platforms). The resultContinuar lendo “Qual a relação entre biodiversidade e o ambiente tectônico? What is the relation between biodiversity and the geological setting?”

#thinsectionthursday

Rhander Taufner Durante o espalhamento da crosta oceânica gabroica nas dorsais meso-oceânicas lentas e ultra-lentas, as zonas de cisalhamento em grande escala crustal acomodam a maioria dos movimentos das placas em falhas de descolamento. O fluxo de material fundido e fluidos quentes em profundidade ao longo dessas falhas produz fontes hidrotermais no assoalho oceânico, nasContinuar lendo “#thinsectionthursday”

Colunas e disjunções prismáticas em lavas basálticas

As disjunções colunares são fraturamentos prismáticos que ocorrem em basaltos ou em outros tipos de rochas ígneas e são resultados do processo de resfriamento do magma. Devido à diferença de temperatura entre a lava e a rocha encaixante (ou ar), ocorre um resfriamento acelerado, de fora para dentro do derrame. Esse resfriamento é responsável pelaContinuar lendo “Colunas e disjunções prismáticas em lavas basálticas”

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”

Graphite deposits, burial of organic carbon and the first appearance of complex life forms / Depósitos de grafita, soterramento de carbono orgânico e a primeira aparição das formas de vida complexas

Graphite is a natural form of carbon crystallized under lower pressures and temperatures than those needed to stabilize diamond. It is a very important mineral resource with applications in the steel industry, as a lubricant, in refractories, paints, oven and brake linings, brushes, batteries, electrodes, pencils, explosives, magnetic tapes, fertilizers and in the making ofContinuar lendo “Graphite deposits, burial of organic carbon and the first appearance of complex life forms / Depósitos de grafita, soterramento de carbono orgânico e a primeira aparição das formas de vida complexas”

PLAGIOGRANITE – a very important component of the ocean floor!

PLAGIOGRANITO – um componente muito importante do fundo do oceano! Do you know what plagiogranite is? This very special type of granite is composed of plagioclase with small amounts of quartz and ferromagnesian minerals. They were long recognized as very important parts of ophiolitic complexes, rocks that represent ancient pieces of ocean floor that areContinuar lendo “PLAGIOGRANITE – a very important component of the ocean floor!”

Aragonite crystal fans in 3D

Aragonite crystal fans in three dimensional view, with pseudo-hexagonal sections in the surface where the coin is resting and prismatic sections in the side cut. Those beautiful crystals are precipitated directly on the seafloor when the ocean is supersatured in CaCO3. This happened ca. 630-540 million years ago, after a global glaciation created ice capsContinuar lendo “Aragonite crystal fans in 3D”