This article examined the use of the <sup>40</sup>Ar/<sup>39</sup>Ar incremental heating and K/Ar analyses to date dolerites located in the extreme north region in Brazil. The material used for...This article examined the use of the <sup>40</sup>Ar/<sup>39</sup>Ar incremental heating and K/Ar analyses to date dolerites located in the extreme north region in Brazil. The material used for dating was whole rock and separated minerals（plagioclases,pyroxene or/and amphibole）in 6 samples of dykes and sills from Roraima.The dolerites yield plateau ages ranging from 1955±17 Ma to 1179±10 Ma.The reason展开更多
文摘This article examined the use of the <sup>40</sup>Ar/<sup>39</sup>Ar incremental heating and K/Ar analyses to date dolerites located in the extreme north region in Brazil. The material used for dating was whole rock and separated minerals（plagioclases,pyroxene or/and amphibole）in 6 samples of dykes and sills from Roraima.The dolerites yield plateau ages ranging from 1955±17 Ma to 1179±10 Ma.The reason
