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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 Geological Survey of India did not focus much on geological mapping in Bengal during the British Raj. The Geological Survey of Pakistan, when Bangladesh was East Pakistan focused on searching for mineral deposits and the Bengali government has continued that pattern. Compared to many countries, the geology of Bangladesh is poorly mapped and ...
Chronostratigraphy is the branch of stratigraphy that studies the ages of rock strata in relation to time.. The ultimate aim of chronostratigraphy is to arrange the sequence of deposition and the time of deposition of all rocks within a geological region, and eventually, the entire geologic record of the Earth.
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.
The geological time scale encompasses the history of the Earth. [13] It is bracketed at the earliest by the dates of the first Solar System material at 4.567 Ga [ 14 ] (or 4.567 billion years ago) and the formation of the Earth at 4.54 Ga [ 15 ] [ 16 ] (4.54 billion years), which is the beginning of the Hadean eon – a division of geological time.