Sutural amplitude of ammonite shells as a paleoenvironmental indicator
Article first published online: 9 OCT 2007
Volume 24, Issue 2, pages 219–225, April 1991
How to Cite
BATT, R. J. (1991), Sutural amplitude of ammonite shells as a paleoenvironmental indicator. Lethaia, 24: 219–225. doi: 10.1111/j.1502-3931.1991.tb01469.x
- Issue published online: 9 OCT 2007
- Article first published online: 9 OCT 2007
- received 9th August, 1990, revised typescript accepted 3rd January, 1991.
The Sutural Amplitude Index (SAI), obtained by measuring the maximum height of sutural elements and the length of the suture pattern on ammonoid shells, provides a useful indicator of relative habitat depth for ammonoids with similar shell morphotypes. A higher SAI indicates greater septal support for the shell wall against implosion under increased hydrostatic pressures in deeper waters. Relating the sutural amplitude indices of ammonites found in a well-studied depositional basin, such as the Cretaceous Western Interior Seaway, to morphotype distributions illustrates the utility of this index in bathymetric interpretations. □Ammonoidea, sutures, Sutural Amplitude Index, Cretaceous, Greenhorn Cyclothem. Western Interior.