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Plate Tectonics

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Japan volcano: 30 hikers feared dead on Mt Ontake. 28 September 2014Last updated at 03:56 ET The BBC's Rupert Wingfield-Hayes says the continuing eruptions have hampered rescue efforts Thirty hikers have been found lifeless near the peak of Mount Ontake, after Saturday's sudden volcanic eruption. The hikers were not breathing and their hearts had stopped, reports said. Final confirmation of death in Japan always comes via a medical examination.

About 250 people were trapped on the slopes of the popular beauty spot, but most have got down safely. The volcano, about 200km (125 miles) west of Tokyo, erupted without warning on Saturday, spewing ash and rocks. The eruption forced many of those on the mountain to make emergency descents through clouds of volcanic ash and falling rocks. Almost 50 people were thought to have stayed on the mountain overnight, reports said. Eyewitnesses and helicopters caught dramatic images of the eruption Confirmation soon came that a similar number of people had been found unresponsive on the mountain. No warning. Crystal is 'oldest scrap of Earth crust' A tiny 4.4-billion-year-old crystal has been confirmed as the oldest fragment of Earth's crust. The zircon was found in sandstone in the Jack Hills region of Western Australia. Scientists dated the crystal by studying its uranium and lead atoms.

The former decays into the latter very slowly over time and can be used like a clock. The finding has been reported in the journal Nature Geoscience. Its implication is that Earth had formed a solid crust much sooner after its formation 4.6 billion years ago than was previously thought, and very quickly following the great collision with a Mars-sized body that is thought to have produced the Moon just a few tens of millions of years after that.

Before this time, Earth would have been a seething ball of molten magma. But knowledge that its surface hardened so early raises the tantalising prospect that our world became ready to host life very early in its history. "We have no evidence that life existed then. 2. A2 Plate Tectonics Content. Observe an animation of the breakup of Pangaea. Wegener's Puzzling Evidence Exercise (6th Grade) Although Alfred Wegener was not the first to suggest that continents have moved about the Earth, his presentation of carefully compiled evidence for continental drift inspired decades of scientific debate. Wegener's evidence, in concert with compelling evidence provided by post World War II technology, eventually led to universal acceptance of the theory of Plate Tectonics in the scientific community.

The following files are needed for this exercise and can be downloaded in pdf format (Teacher Overview, (For Teachers) Wegener's Key to Continental Positions for grade 6, Student Puzzle Pieces, Key to Wegener's Evidence sheet, and Student Map of the World Today). If students need additional hints beyond those provided below, there is a Puzzle Outline Hint to be used as a base for the puzzle. Objectives Students will observe and analyze scientific evidence used by Wegener. The Student Puzzle Pieces and Legend To start this activity the teacher will present background information on Wegener.