* Evaluated fields could hold 35 bln barrels * Subsalt auction to be held Nov. 28 RIO DE JANEIRO, March 12 (Reuters) - Areas of Brazil's giant subsalt oil and gas region explored so far could yield 35 billion barrels of recoverable oil equivalent, more than double Brazil's existing reserves, an energy ministry representative said on Tuesday. That is more than the 17.9 billion barrels of discovered recoverable oil Brazil's ANP oil regulator said the subsalt area had in 2011. Analysts have said the total amount of oil in the region could be 100 billion barrels. "Subsalt discoveries that have been evaluated so far suggest a volume of recoverable oil more than double Brazil's proven reserves," said Marco Antonio Martins Almeida, secretary of oil and gas at Brazil's Ministry of Mines and Energy. He described the estimate as conservative at a conference in Rio de Janeiro. Brazil's current oil reserves are an estimated 14.52 billion barrels, according to the ANP. The BM-S-8 block operated by state-led oil company Petrobras in the Santos Basin alone likely has 1 billion barrels of recoverable oil, he said. Petrobras said it found good-quality oil in the Carcara well in the block, located in the Santos Basin, on Jan. 2. Almeida said exploration rights to subsalt fields, a region the size of New York State where oil was discovered in 2007, will be auctioned to private investors on Nov. 28 under a new regulatory framework for the industry in Brazil. Brazil will also auction 289 blocks outside the subsalt region in its 11th-around auction on May 14 and 15 in Rio de Janeiro, its first offering in five years.