* Duma votes to ratify Barents Sea boundary with Norway
* Norwegian oil and gas studies to follow final ratification
* Formalities all that remain after "big step" by Duma
By Walter Gibbs
OSLO, March 26 (Reuters) - Norway welcomed a Russian State Duma vote ratifying a treaty to divide the Barents Sea into clear Norwegian and Russian zones, bringing Norway closer to a new oil and gas drive in the Arctic.
"The action in the Duma is gratifying, and is a big step toward implementing the agreement," Norwegian Ministry of Foreign Affairs spokesman Kjetil Elsebutangen said on Saturday, a day after Russia's lower house of parliament ratied the deal.
Earlier this month, Norwegian Prime Minister Jens Stoltenberg said Norway would begin a formal study into offshore oil and gas exploration along the newly delineated boundary in the Barents Sea soon after Russia ratifies the treaty.
Approval by Russia's upper house, or Federation Council, is considered a formality as it regularly rubber stamps initiatives from President Dmitry Medvedev, who helped negotiate the Barents treaty in Oslo and signed off on its terms last September.
Norway's parliament ratified it on February 8.
Elsebutangen said the line, running between Norwegian and Russian archipelagos most of the way to the North Pole, will become law 30 days after Medvedev signs it and the two countries formally "exchange documents".
"We hope that won't take long," he said, adding that the deal "will open the way for new rules on new opportunities to exploit resources."
The area to be divided after 40 years of dispute is about half the size of Germany.
Seabed scans conducted by the former Soviet Union reportedly indicated significant oil and gas deposits. Norwegian companies led by Statoil (STL.OL) have said finds there could help revive national production that has been declining for a decade.
In the Duma the majority United Russia Party supported the treaty with Norway while the Communist Party objected on grounds that it could hurt Russian fisheries interests, Itar-Tass reported. The final vote count in the Duma was not given.
Editing by Ralph Boulton