parent-daughter isotopic ratios) with known rates of decay (half-lifes).Potassium makes up Ca decay branch has largely been unexploited (although see discussion by Harrison & Lovera 2013).Standing roughly in the centre of New Zealand’s North Island, Mt Ngauruhoe is New Zealand’s newest volcano and one of the most active (Figures 1 and 2).It is not as well publicized as its larger close neighbour MT Ruapehu, which has erupted briefly several times in the last five years.The name "argon" is derived from the Greek word meaning "lazy" or "inactive", as a reference to the fact that the element undergoes almost no chemical reactions.
It’s not clear what the protest is supposed to be about — many of the signs read general phrases like “Join the conversation” and “love.” Beckoned by one of the protesters, Jenner eventually rips off her blonde wig and joins the fray.
Mt Ngauruhoe is thought to have been active for at least 2,500 years, with more than 70 eruptive periods since 1839, when European settlers first recorded a steam eruption.2 Of course, before that, the Maoris witnessed many eruptions from the mountain.
The first lava eruption seen by Europeans occurred in 1870.3 Then there were ash eruptions every few years until a major explosive eruption in April–May 1948, followed by lava flowing down the northwestern slopes in February 1949.4 These flows are still distinguishable today on the northwestern and western slopes of Ngauruhoe (Figure 4).
It’s hard not to compare the image of Jenner handing the can to the police officer to the award-winning photo from a Baton Rouge, La., protest against police brutality last July.
In it, Ieshia Evans can be seen, calm and collected, offering her hands for arrest to a group of riot-gear-clad police officers.
Nearly all of the argon in Earth's atmosphere is radiogenic argon-40, derived from the decay of potassium-40 in the Earth's crust.