Garruk Wildspeaker untap target same land twice? magic

[computer]

can I use first ability of Garruk Wildspeaker to, say, untap a Copperline Gorge that came into play tapped that turn, tap it for G, then untap it again, tapping it for R, ending with having GR in your mana pool?

[Arix]

No, you have to target two different lands. And even if you could target the same land twice, you wouldn't be able to tap it for mana in between anyway.