EMERGING MARKETS-Real drops on pre-holiday caution; Chile cenbank awaited

RIO DE JANEIRO, April 17 (Reuters) - The Brazilian real weakened more than half a percentage point on Thursday as investors turned cautious ahead of a long holiday weekend, while the Chilean peso edged lower ahead of a key central bank decision on interest rates. Trading volumes were thin as many traders took off for the Easter holiday; the Mexican bourse was closed on Thursday. Brazilian financial markets will be shut on Friday and will not reopen until on Tuesday, because the country c