Johnny Van Zant became the lead vocalist for Lynyrd Skynyrd in concerts.
-RCB- -RCB- em ''. |  align = `` center '' colspan = 2 style = `` background-color  : ''  |  Zirconian Era4404 -- 4031 million years ago. |  -. |  align = `` center '' colspan = 2  |. |  -. |  -RCB-. The Zirconian is considered to be proposed revision of the Precambrian time scale the second era within the Hadean eon .. Precambrian. Precambrian. era. era. Hadean. Hadean. It lasted 373 million years from the end of the Chaotian Era to the beginning of Eoarchean Era .. Chaotian. Chaotian ( geology ). Eoarchean. Eoarchean. The Zirconian follows the Chaotian Era and its beginning is chronometrisch set at 4.404 ± 0.008 Gya .. Chaotian. Chaotian ( geology ). Gya. Gya. This corresponds to the age of the first occurrence of zircons in the Jack Hills in Western Australia -LRB- Yilgarn craton -RRB- .. Jack Hills. Jack Hills. Western Australia. Western Australia. Yilgarn craton. Yilgarn craton. Its end and the transition to the Archean Eon , Eoarchean Era and its earliest period , the Acastan Period , carried out with the appearance of the oldest rock at 4.031 ± 0.003 Gya .. Eoarchean. Eoarchean. Gya. Gya. Archean. Archean. Acastan. Acastan. rock. Acasta Gneiss