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This is a list of Global Boundary Stratotype Sections and Points.Since 1977, Global Boundary Stratotype Sections and Points (abbreviated GSSPs) are internationally agreed upon reference points on stratigraphic sections of rock which define the lower boundaries of stages on the geologic time scale.
The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronology (a scientific branch of geology that aims to determine the age of rocks).
Because defining a GSSP depends on finding well-preserved geologic sections and identifying key events, this task becomes more difficult as one goes farther back in time. Before 630 million years ago, boundaries on the geologic timescale are defined simply by reference to fixed dates, known as "Global Standard Stratigraphic Ages" (GSSAs).
In the stratigraphy sub-discipline of geology, a Global Standard Stratigraphic Age, abbreviated GSSA, is a chronological reference point and criterion in the geologic record used to define the boundaries (an internationally sanctioned benchmark point) between different geological periods, epochs or ages on the overall geologic time scale in a chronostratigraphically useful rock layer.
The following five timelines show the geologic time scale to scale. The first shows the entire time from the formation of the Earth to the present, but this gives little space for the most recent eon. The second timeline shows an expanded view of the most recent eon.
Geologic Time Spiral Historical geology or palaeogeology is a discipline that uses the principles and methods of geology to reconstruct the geological history of Earth . [ 1 ] Historical geology examines the vastness of geologic time, measured in billions of years, and investigates changes in the Earth , gradual and sudden, over this deep time .
Download QR code; Print/export ... International Commission on Stratigraphy geologic time scale of Earth (4 C, 2 P, 1 F) M. ... Pages in category "Geologic time ...
A non-standard geologic time period immediately preceding the Phanerozoic Eon, divided into several eons of the geologic time scale. It spans from the formation of Earth about 4540 Ma (million years ago) to the beginning of the Cambrian Period , about 541.0 ± 1.0 Ma, when macroscopic hard-shelled animals first appeared in abundance.