The top routes that United Airlines flies are: 1  CLT to ORD with 3,755 flights per month. 2  CLT to IAH with 3,511 flights every month. 3  DFW to ORD with 3,486 flights every month.  DFW to EWR with 3,268 flights every 1  month. PHL to ORD with 3,238 flights every month.
The first of the three rock types to form on Earth were the igneous rocks; formed from the cooling and solidification of magma, as the Earth was at one time completely molten. â¦. 4 people found this useful.
Jack Hills, Australia, where rocks were found to contain the oldest known minerals on Earth, a 4.4 billion-year-old zircon. Credit: John Valley, University of Wisconsin.View full size image. Just three of the very oldest zircons have been found, ones that date back to almost 4.4 billion years ago.y zapping single atoms of lead in a tiny zircon crystal from Australia, researchers have confirmed the crystal is the oldest rock fragment ever found on Earth â 4.375 billion years old, plus or minus 6 million years.