Geology news

Earthquake synchrony

At we are informed that in nature random signals often fall mysteriously in step, one after the other. Fireflies flashing sporadically in the early evening have a tendency to flash in unison, or very closely after each other - flashing in bunches, and a similar harmonic behaviour can be conjectured while listening to crickets (grasshoppers) or even swinging clock pendulums.

Rare Earth Elements

At June 15th ... mentions the recently discovered mineral wealth of Afghanistan, worth an estimated one trillion dollars. These include rare earth elements such as dysprosium, erium, and ytterbium which are found concentrated in ores and these and other strangely named elements are used in computer hard drives, TV screens, and smartphones, LED lights, and magnets in electronics, wind turbines and hybrid cars etc.

Tibet Glacier ... glaciers in Tibet were never much larger than they are now -  even at the height of the Ice Age and in spite of the fact the plateau is the largest and highest mountain region in the world. The researchers, using a mathematical model, have shown that a small fall in temperature, around 5 degrees (which is not much, relative to the annual fall in temperatures during the Ice Ages) would cause a small ice sheet to start to form, and that would grow.

The Yangtze River

Again, at ... we are told the Yangtze River is 40 million years older than previously thought because a study of minerals by a team from Durham University says the river began to cut hrough the Three Gorges area around 45 million years ago. The Three Gorges is in SW China and cuts through a range of inaccessible mountains that surround Sichuan Province, the rice bowl of China.

Volcanoes and the Mantle

See ... if tectonic plates colliding cause volcanoes why do some volcanoes erupt far from a plate boundary? A study in Nature suggests that volcanoes, and even mountains, in the Mediterranean region, can grow from the pressure of the semi liquid mantle pushing on earth's crust from below.

Earthquake clustering is a post on earthquakes triggering other earthquakes, causing clusters of them - which involves the synchronisation of faults in the crust. The synchronisation of earhquakes - clusters of ruptures of several faults followed by phases of quiescence has apparently been found in palaeo-seismic records (or proxy data). It reflects the common observation that large earthquakes can trigger others on nearby fault lines.

Himalayan Smack

At May 28th ... geologists have found evidence that when India collided with Asia 90 million years ago the crust of the Indian tectonic plate was forced beneath the larger Asian plate and sank into the mantle of the earth to a depth of at least 200km. This is double that of previous estimates.

Timor Sea Crater

At ... Australian scientists have found a crater at the bottom of the Timor Sea and this has been dated (how?) contemporary with a heavy bombardment event some 35 million years ago. Archaeologist Andrew Glikson said the identification of microstructural and chemical features in drill fragment revealed further evidence of impact saying it was a 50km wide scar.

Fish Extinctions

At it is claimed a mass extinction of fish some 360 million years ago reset the button on earth's life forms triggering modern vertabrae biodiversity. The mass extinction event, it is theorised, scrambled the species pool near the juncture when the first vertebrae were crawling out of the water on to the land.

Layering of Loess

At Nigel Calder has a post on the 1960s discovery by Czech geologist George Kukla, who counted the layers of loess, each separated by darker bands of material thought to be left over from warm interglacial periods. Kukla found too many layers of loess - and this did not fit into current thinking. Until then everyone had been thinking in terms of just four Ice Ages.