and/or two distinct absorption components. There is broad consensus that the red component of the profile is from Ca H&K at a “photospheric” velocity, i.e., a velocity similar to that of the ejecta at close to the $\tau = 2/3$ surface, which is typically about 12000 [kms$^{-1}$]{} near maximum light. However, there is no clear consensus to the origin of the blue component. Previous studies have attributed the blue absorption component to either “high-velocity” (HV) Ca H&K absorption [[$\sim\!\!$ ]{}18,000 [kms$^{-1}$]{}; e.g., @Hatano99:94d; @Garavini04; @Branch05; @Branch07; @Stanishev07:03du; @Chornock08; @Tanaka08; @Tanaka11; @Parrent12], where the absorption comes from a region at high velocity within the SN ejecta that has high-density calcium, and to [Si$\,$]{} $\lambda\lambda 3854$, 3856, 2863 [$gf$-weighted rest wavelength of 3858 Å; e.g., @Kirshner93; @Hoflich95; @Nugent97; @Lentz00; @Wang03; @Altavilla07]. Since calcium and silicon produce the strongest features in SN Ia spectra near maximum brightness, both interpretations are worth investigation. For convenience, we will generally refer to this feature as the “Ca H&K feature.”

There are several cases of clear HV material in SNe Ia. Observations showing multiple components to the [Si$\,$]{} $\lambda 6355$ line profile [e.g., @Mazzali05:99ee; @Altavilla07; @Garavini07:05cf; @Stanishev07:03du; @Wang09:05cf; @Foley12:09ig] or strong and quickly varying HV [O$\,$]{} $\lambda 