The grant will see six hectares of Broadcroft Quarry in Portland, Dorset, restored and opened as a trail.
The two-year project is one of the first steps towards the main Jurassica attraction, which is planned in the 40m (132ft) deep quarry.
The work will see a team of more than 100 volunteers work with conservation experts at the Dorset Wildlife Trust.
Funding for the attraction is being raised through donations, grants and sponsorship from businesses.
The proposed subterranean park on the World Heritage Site would see a glass and steel roof, about a third the size of the Millennium Dome, installed over the quarry.
It would house an aquarium with robot swimming plesiosaurs, fossils and interactive displays.
The charity behind the museum, which will cover three geological time periods, said it planned to submit a full planning application later this year.
Sir David Attenborough is the project's patron and the Eden Project's Sir Tim Smit is its trustee. It also has the backing of the Royal Society and the Natural History Museum.
Jurassica is the idea of science writer Michael Hanlon who died last year aged 51 after a heart attack.

Dana was transported to the Al-Mawa reserve via Turkey along with four other lions, two bears and two tigers in a three-month operation organised by the animal welfare charity Four Paws.
Staff found the cub, who they named Hajar, in her cage on Saturday.
They are now waiting to see whether Dana will give birth to a second cub.
Dr Amir Khalil, a vet who accompanied the animals, told the Associated Press on Sunday that an ultrasound performed in Turkey had shown she was carrying two.
However, he warned that the second cub might already have been born dead and been eaten by Dana.
Its fate will not be known until another ultrasound is carried out on Monday.
Four Paws said its team had initially been very concerned about whether Dana would accept or kill Hajar because of the enormous stress she had endured.
"But luckily that wasn't the case. She cleaned the cub and nursed it," the charity added. "This is a true sign that she feels safe at Al-Mawa."
Hajar's gender is unknown because staff have not been able to examine the cub.
Plans for an Â£80m dinosaur-themed museum in a quarry have been boosted by Â£37,300 of Heritage Lottery Funding.
[NEXT_CONCEPT]
A lioness rescued from a zoo in the war-torn Syrian city of Aleppo has given birth just hours after arriving at a wildlife park in Jordan.