Here you go: the gateway.
I'm feeling a bit worn out, so I'm just going to get to writing.
They had been standing in the afternoon sun for over an hour, each of the men studying the runes in the arch with a magnifying glass in one hand and a reference book in the other. Tilley hats protected them from the sun's rays but not the biting particles of sand the wind insisted on sending their way in a steady stream.
"They're so familiar," one muttered with a shake of his head, "yet so... foreign."
"Just when I think I've figured out a pattern," the other replied, "the next symbol throws my theory out like used toilet paper. It's bloody maddening."
They returned to their silent inspections, the rest of the dig team busying themselves with preparations for dinner a hundred feet behind them. Neither of the men felt even remotely hungry.
"This one here is repeated five times, at irregular intervals," one said a while later, a sun-darkened finger touching a symbol that was just above eye level. "Well, irregular to my eye anyway."
"And this one repeats four times," his partner said. "But look, here it continues under the arch and to the other side. I wonder if -"
The man twisted his head around to look at the opposite side of the arch, lost his balance, stumbled forward a few steps, and promptly vanished into thin air.
"Great," the man left behind said with a sigh. "Now I'll never know what he was thinking."