Virtual Field Study
Quantifying the Data
If you had several shells in front of you do you think you could tell them apart? When it comes to the shell of a bivalve there are not a lot of obvious features that can be measured. Two features that have been identified and quantified are changes in shell thickness and interval volume. In order to study the change in shell morphology over time, shells must be collected from horizons spanning a range of rock ages at an outcrop. Once those shells are collected they must then have their interval volume and shell thickness documented. The quantification of these features is done in a laboratory with a pair of calipers, some fine sand, and a cylinder.
The internal volume of a shell is defined as the space available inside
the shell. For Anadara and Astarte, shell volume was determined by
filling a shell with fine sand and then pouring that sand into a graduated
cylinder and recording the volume in milliliters.
The shell thickness was obtained by measuring, using a pair of calipers, the thickness of the shell at its center, where it is thickest. This measurement was recorded in millimeters.
Last modified October 06 2008 03:08 PM