The blogger is a vertebrate paleontologist specializing in the Triassic Period, the Beginning of the Age of Dinosaurs.
My posts are presented as opinion and commentary and do not represent the views of Lab Spaces Productions, LLC, my employer, or my educational institution.
The biostratigraphic situation can be summarized as a vertically-stacked sequence of "zones" defined by the first appearance of each ammonite species: Figure.
Charles Darwin explained the mechanism behind it - evolution.
In biostratigraphy, we subdivide time into units called biozones/biochrons, defined at their bases by bioevents.
These zones are given short alphanumeric names, e.g., UC1-20 for the upper Cretaceous, NP1-25 for the Paleogene and NN1-21 for the Neogene and Quaternary.
Index fossils are fossils used to define and identify geologic periods (or faunal stages).
They work on the premise that, although different sediments may look different depending on the conditions under which they were laid down, they may include the remains of the same species of fossil.
Their small size means they can be studied from minute rock chips, which is of particular value in hydrocarbon exploration and development, and scientific drilling.Biostratigraphy is a sub-discipline of sedimentary geology that relies on the physical zonation of biota, both in time and space, in order to establish the relative stratigraphic position (i.e.older, younger, same age) of sedimentary rocks between different geographic localities.Dental hypoplasias Suspensory locomotion is characteristic of macaques The "Lucy" skeleton, a member of Australopithecus afarensis, was discovered.The simplest situation for a geologist is a "layer cake" succession of sedimentary or extrusive igneous rock units arranged in nearly horizontal layers. Radiometric dating provides numerical values for the age of an appropriate rock, usually expressed in millions of years.