(a) This chapter does not govern an adoption proceeding or a proceeding pertaining to the authorization of emergency medical care for a child.
(b) A child custody proceeding that pertains to an Indian child as defined in 25 U.S.C. 1901 — 1963 (Indian Child Welfare Act of 1978) is not subject to this chapter to the extent that it is governed by 25 U.S.C. 1901 — 1963 (Indian Child Welfare Act of 1978).