Villain had been loose aggressive, raising many pots preflop. Is this a monster or blind defense by the big stack? What's your calling range here?

PokerStars No-Limit Hold'em Tourney, Big Blind is t100 (6 handed) FTR converter on zerodivide.cx

CO (t2100)
Hero (t1265)
SB (t4530)
BB (t1590)
UTG (t1925)
MP (t2090)

Preflop: Hero is Button with A, T.
3 folds, Hero raises to t300, SB raises to t1550, 1 fold, Hero ?????