Cretaceous-Tertiary (Chicxulub) impact angle and its consequences

The Chicxulub impact structure exhibits asymmetries in its geophysical signatures that closely resemble asymmetries produced by oblique impacts in laboratory experiments and recognized on planetary surfaces. These asymmetric signatures suggest a trajectory for the Chicxulub bolide from the southeast to the northwest at a 20 degrees -30 degrees angle from the horizontal. As a result, biotic extinctions may have been most severe and catastrophic in the Northern Hemisphere. Geographic variation in the magnitude of the Cretaceous-Tertiary (K-T) "fern spike" and palynofloral extinctions are consistent with the proposed trajectory.