first appearance datum造句

• A land vertebrate faunachron ( LVF ) is a time interval that is defined by the first appearance datum ( FAD ), or first occurrence, of a tetrapod index fossil and is commonly used to date Late Triassic and Early Jurassic terrestrial strata.
• The International Commission on Stratigraphy ( ICS ) has assigned the First Appearance Datum of " Hindeodus parvus " as the defining biological marker for the start of the Induan, 252.2 ?0.5 million years ago, the first stage of the Triassic.
• In 2011, a study discovered that the First appearance datum ( FAD ) of " Iapetognathus fluctivagus " in the Global Boundary Stratotype Section and Point ( GSSP ) section in Green Point may not actually be the earliest species of " Iapetognathus " to appear as was earlier believed.