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Reconstructed chemical composition of the oceans Before then ...

Researchers have recently focused their studies on Doushantuo formation in South China. Today, the news in early March, the analysis of rocks has enabled scientists to reconstruct the chemical composition of the oceans in the Ediacara period (between 635 and 551 million years ago). This first reconstruction of the primitive composition of the oceans will help to understand the early evolution since the single-celled organisms. It represents a new piece to the puzzle of evolution.

The first information on the presence of fossils in the Doushantuo Formation in China date back to 1998 when he described the presence Xiao algae with cellular structure preserved in three dimensions and embryos during cleavage
extremely well preserved phosphatic deposits that characterize this formation extend over an area of \u200b\u200babout 52 square kilometers in the central region of Guizhou. They are, therefore, a large collection of. Study material useful for understanding the evolution of life from its most stadiums' old. In NANTU formation, geological formation created in a kind of post-glacial dropstones be found, till and pebbles, which show the characteristic signs connected to an erosion glaciale.

Anche lungo le pareti delle gole dello Yangtze si rinvengono  importanti indizi quali successioni di rocce fosfatiche e carbonatiche che si sono accumulate durante due cicli di innalzamento ed abbassamento del livello marino. I test indicano che l'ambiente di deposizione era caratterizzato da un'alta salinità, come si puo' trovare ad esempio in lagune, con bassa concentrazione di ossigeno e basso tasso di sedimentazione.

Nella formazione di Doushantuo, si rinvengono oltre alle frequenti colonie di cianobatteri, anche microfossili che hanno reso famosa questa formazione. Si tratta di organismi essenzialmente sferoidali di dimensioni in genere inferiori to 600μm, with friezes complex as pins, nodes, different growths.

The most significant finding, however, was that of spherical cells of 400-500μm in diameter near the village of Weng'an. The balls, as homogeneous morphology, showing stages of cell division in two, four, eight and so on in the sequence typical of exponential cell division. These forms were considered as fossil embryos, a rarity, but do not know what kind of body they may have belonged. And it was starting from an appointment with these exceptional finds that ki scientists began to explore and investigate, inter alia, have come to this discovery

photos - scienceblogs.com /