Taxonomy term

basalt

Columbia River basalts erupted faster than thought

In the Pacific Northwest, oozing volcanic basalts erupted over the landscape during the middle Miocene, layering a sequence of 43 distinct strata, comprising roughly 350 individual flows, up to 2 kilometers thick over roughly 210,000 square kilometers. The timeline over which all that rock, known as the Columbia River Basalt Group (CRBG), piled up — and the pace at which it did so — hasn’t been as clear as scientists would like, in part because prior dates for the lava flows have come with large uncertainties. But in a new study in Science Advances, researchers have reduced those uncertainties and shown that the vast majority of the massive CRBG was deposited in less than a million years.

07 Jan 2019

Did volcanism drive Earth into global glaciation?

Between about 720 million and 635 million years ago, Earth suffered two big chills. During these “Snowball Earth” episodes, geologists think the world’s oceans froze over and glaciers spilled from tropical coastlines. Scientists have previously suggested that intense volcanism, unleashed by the disintegration of the supercontinent Rodinia, plunged Earth into these global glaciations. New research now lends support to this so-called fire-and-ice hypothesis.
05 Jun 2015

The Syracuse University lava experiments

Pouring Lava

Melting a batch of the ancient basalt takes about four hours, but we hold the lava above its melting point for much longer to ensure that it is completely melted and to remove unwanted volatiles such as water. The lava is then poured at temperatures of 1,100 to 1,350 degrees Celsius, comparable to eruption temperatures of natural lava. We monitor it with a spot calorimeter and a Forward-Looking Infrared (FLIR) camera, the same instrument conventionally used at lava flows in the field.

20 Aug 2012

Benchmarks: August 1975: Geotimes magazine inspires name of rock formation: A Q&A with Tony Alabaster

In August 1975, an intriguing rock formation in Oman appeared on the cover of Geotimes magazine, EARTH magazine’s predecessor. This pillow lava — a type of rock that forms when hot molten basalt flows into water, such as happens in Hawaii, or erupts underwater — is one of the lowermost units of the now-famous Semail ophiolite sequence. Ophiolites, pieces of ancient oceanic crust and upper mantle later uplifted and exposed on land, were a hot geological topic in the 1970s, because they helped illuminate the process of seafloor spreading, a key puzzle piece supporting the then-revolutionary theories of continental drift and plate tectonics.
 
09 Aug 2010