When“Lost” ended its six-season run, it was tempting to view its sign-off as the closing of another chapter: the era of big-budget, high-concept drama on network television. With the economy still shaky and the memory of flameouts like “Heroes” and “FlashForward” still fresh, it seemed that the ABCs and Foxes of the world would wait before investing in another ambitious series with motion-picture-level production values.

Yet here we are at the dawn of the 2011-12 fall TV season, gazing wide-eyed at the behemoth that is “Terra Nova,” Fox’s high-concept, big-budget drama about a family that scores a one-way trip away from the environmentally decimated Earth circa 2149 to the fresh air and verdant lands that existed 85 million years prior. Like “Lost” before it, “Terra Nova” features time travel, jungle chases and terrifying creatures, but here, they’re dinosaurs instead of smoke monsters and polar bears.

“Terra Nova,” which debuts Sept. 26 on Fox, isn’t just some “Lost” knockoff, nor is it the only fall TV series with a fantastical premise (NBC’s “Grimm” and ABC’s “Once Upon a Time,” for example). It’s also not the only new show that requires significant cash to produce. The pilot for “Terra Nova” cost $10 million to $20 million, according to the Hollywood Reporter, an amount amortized over the course of the season. (Executive producer Rene Echevarria says the price tag averages out to about $4 million for each of the first season’s 13 episodes.) Similarly, the pilot for ABC’s new series “Pan Am” cost $10 million, according to the New York Times. And that show doesn’t even have computer-generated images of prehistoric beasts — beasts that require an additional six to eight weeks of “Terra Nova” post-production time.

But given its positive early buzz, the visual effects required to bring all those carnosaurs to life and the involvement of a dozen producers — including some guy named Steven Spielberg, who knows a little something about dinosaur stories — “Terra Nova” stands as perhaps the most closely watched go-big-or-go-home drama of the new season. The key question it faces: Can a series with the production values and sensibility of a summer blockbuster win enough fans to justify the network’s investment?

Echevarria is hoping so.

“This is starting out on the high end of the spectrum, no doubt,” he said during a recent phone interview. “It was clear from the concept this is not going to be a cheap show to produce. So the studio and the network need[ed] to decide upfront if they want that kind of event programming.”

Fox decided it does. The network committed upfront to all 13 episodes and weathered the storm — literally, as heavy rains often presented challenges on the set in Queensland, Australia — as production delays and the demands of all those elaborate effects pushed the pilot’s premiere from January 2011 to May, then to September.

“There was no real delay,” Echevarria jokes, acknowledging that TV reporters and bloggers paid close attention to the setbacks. “We did that all as a marketing thing to create sort of word of mouth.”

Fox genuinely is trying to generate word of mouth. The network has put some guerilla marketing muscle behind the show by sending out the “Journey to Terra Nova Mobile Experience” — a bus tricked out with interactive, buzz-generating features that allow potential fans to do such things as photographing themselves in the world of Terra Nova and sharing the pictures via social networking sites. (Coincidentally, it’s stopping in the District and Baltimore this weekend, should you wish to climb aboard this marketing machine on wheels.)

That suggests that the network and the creative team might be aiming for a younger, Internet-chatter-prone demographic. But Echevarria says the audience, like the ambitions surrounding “Terra Nova,” is potentially grander than that. He points out that the narrative’s central protagonists, the Shannon family, includes a middle-age mom and dad, a couple of teenagers and a 5-year-old girl. Another selling point: It has the potential to catch on in foreign markets. Echevarria says there are plans to air it in Australia, the U.K. and other European countries.

“I think everyone is sort of tip-toeing back into the water,” he says. “It’s the kind of thing network television can do [financially] that maybe basic cable can’t do.”

As far as whether pricey, high-concept event programming could make a comeback — or, perhaps, never went away — David Bushman, a TV curator at New York’s Paley Center for Media, says television is far too cyclical for anyone to suggest that one type of show is dead.

“If ‘Terra Nova’ is a success, you’ll see shows trying to imitate it, to capture that same magic,” he says.

In other words, if Echevarria and company’s cretaceous-period experiment works, next fall’s new shows can stop trying to be the next “Lost” and start trying to be the next “Terra Nova.”

Terra Nova

debuts at 8 p.m. Monday on Fox.
Pilot is two hours; regular show, one hour.