For a brief time, Jordan's eastern desert blooms. The dozens of mesas commanding the bleak horizons are now skirted with vegetation.

Through binoculars, these charcoal husks of dead volcanoes seem shrouded in green mist.

Birds sing above yellow, red and purple wildflowers peeking up around flint shards and stone carvings. Many carvings are in the ancient Safaitic script, an ancestor of modern Arabic, but others are more recent: a drawing of a long-haul truck and "1999" scrawled in Arabic.

Summer's heat will soon burn the spring colors away, and return the qaa or plains in Arabic to the basalt black, sandy brown sand and sky blue, says Yorke Rowan, an archaeologist who has spent the past seven years studying the dawn of human civilization in Wadi El-Qattafi, Jordan.

He has learned that this desert was grassland with topsoil where long ago humans stalked herds of gazelle and built homes, corrals and hunting traps.

Semi-nomadic peoples built "Neolithic hamlets" used during seasonal hunting, shepherding and perhaps farming in the 6500 BC to 6000 BC era, Rowan said.

"There's a lot more going on in this desert region that looks like such a blasted, empty territory to our Western eyes, including archaeologists who should know better, that we're starting to discover," he says.

Sixty kilometers from the nearest city, Azraq, Rowan and colleagues in the Eastern Badia Archaeological Project have mapped thousands of these 8,000-year old stone structures, aided by a 21st century technology.

Rowan drives out across the plain to a launch site for a drone, built and operated by archaeologist Austin Hill. Rowan throws it into the sky and Hill pilots the drone and its cameras out over the mesas.

From the air, peculiar shapes form on the slopes of the black mesas: some circular, others kilometers-long.

The large number of structures hints at an environment much more like the today's spring bloom. Human remains, stone knives, arrowheads and seeds discovered at the mesas or nearby at Wisad Pools also support the theory.

Current understanding of the Neolithic era is "undergoing its own revolution," Rowan says.

Archaeologists across the Middle East are re-examining the basic assumptions of humanity's roots. Did the spread of agriculture cause the era's population spike, or was it the other way around?

For now, there remains so much to do with trowel and drones, that Rowan and colleagues named the valley "the land of conjecture".