The Earth’s outer layer is made up of a series of moving, interacting plates whose motion at the surface generates earthquakes, creates volcanoes and builds mountains. Geoscientists have long sought to understand the plates’ fundamental properties and the mechanisms that cause them to move and drift, and the questions have become the subjects of lively debate.
A study published online Feb. 27 by the journal Science is a significant step toward answering those questions. (more…)
NASA’s Curiosity Mars rover has passed the milestone of 100,000 shots fired by its laser. It uses the laser as one way to check which chemical elements are in rocks and soils.
The 100,000th shot was one of a series of 300 to investigate 10 locations on a rock called “Ithaca” in late October, at a distance of 13 feet, 3 inches (4.04 meters) from the laser and telescope on rover’s mast. The Chemistry and Camera instrument (ChemCam) uses the infrared laser to excite material in a pinhead-size spot on the target into a glowing, ionized gas, called plasma. ChemCam observes that spark with the telescope and analyzes the spectrum of light to identify elements in the target. (more…)
Antarctica’s topography began changing from flat to fjord-filled starting about 34 million years ago, according to a new report from a University of Arizona-led team of geoscientists.
Knowing when Antarctica’s topography started shifting from a flat landscape to one with glaciers, fjords and mountains is important for modeling how the Antarctic ice sheet affects global climate and sea-level rise. (more…)
*New research reveals how the arrival of the first plants 470 million years ago triggered a series of ice ages. Led by the Universities of Exeter and Oxford, the study is published in Nature Geoscience.*
The team set out to identify the effects that the first land plants had on the climate during the Ordovician Period, which ended 444 million years ago. During this period the climate gradually cooled, leading to a series of ‘ice ages’. This global cooling was caused by a dramatic reduction in atmospheric carbon, which this research now suggests was triggered by the arrival of plants.
Among the first plants to grow on land were the ancestors of mosses that grow today. This study shows that they extracted minerals such as calcium, magnesium, phosphorus and iron from rocks in order to grow. In so doing, they caused chemical weathering of the Earth’s surface. This had a dramatic impact on the global carbon cycle and subsequently on the climate. It could also have led to a mass extinction of marine life. (more…)
*UA scientists have teamed up to study the relationship between arsenic in human toenails and arsenic concentration in drinking water. Exposure to arsenic is associated with several chronic diseases ranging from dermatitis to various cancers.*
Scientists from the University of Arizona specializing in environmental health sciences and pharmacology and toxicology have teamed up with the help of a seed grant to study the relationship between arsenic in human toenails and arsenic concentration in drinking water.
Arsenic exposure in Arizona is a concern because of naturally occurring contamination of groundwater, said Miranda Loh, assistant professor of environmental health sciences at the UA Mel and Enid Zuckerman College of Public Health. (more…)
*A fossil from north-eastern China has revealed that terrestrial reptiles were giving birth to live young at least as early as 120 million years ago.*
The newly discovered fossil of a pregnant lizard proves that some squamate reptiles (lizards and snakes) were giving birth to live young, rather than laying eggs, in the Early Cretaceous period – much earlier than previously thought. The fossil shows a pregnant female filled with the tiny skeletons of more than 15 baby lizards at a stage of development similar to that of late embryos of modern lizards. The mother lizard, which is 30 centimetres long (excluding her tail), probably died only a few days before giving birth.
The discovery is described in the journal Naturwissenschaften by scientists from UCL (University College London) and the Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences, Beijing. (more…)
