\ε\(_{Nd}\) is the deviation of \(^{143}\)Nd/\(^{144}\)Nd of a sample relative to CHUR in parts per 10\(^4\). For a pyroxenite with measured \(^{143}\)Nd/\(^{144}\)Nd = 0.512838 and \(^{147}\)Sm/\(^{144}\)Nd = 0.21, the initial \ε\(_{Nd}\) at 1 Ga is ............ (Round off only the final answer to one decimal place)