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The North American land mammal ages (NALMA) establishes a geologic timescale for North American fauna beginning during the Late Cretaceous and continuing through to the present. These periods are referred to as ages or intervals (or stages when referring to the rock strata of that age) and were established using geographic place names where ...
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).
The geologic turmoil on the west coast was maintained as the Pacific Plate continued to slide under the North American Plate. [133] During the early part of the Cenozoic period climates were much warmer than they are today. Latitudes as high as South Dakota had a subtropical climate until as recently as the end of the Oligocene. [134]
(Click to zoom) See legend below This is the legend for the North American geological map above. Geologic map of North America. The geology of North America is a subject of regional geology and covers the North American continent, the third-largest in the world. Geologic units and processes are investigated on a large scale to reach a ...
Geologic time is the timescale used to calculate dates in the planet's geologic history from its origin (currently estimated to have been some 4,600 million years ago) to the present day. Radiometric dating measures the steady decay of radioactive elements in an object to determine its age. It is used to calculate dates for the older part of ...
North America Sonoma orogeny.27 .24 North America Nevadan orogeny.2 North America Sevier orogeny.14 .05 North America Laramide orogeny.07 .04 North America Pasadena orogeny.03 North America Sleaford orogeny: 2.44 2.42 Oceania Glenburgh orogeny: 2 1.92 Oceania Barramundi orogeny: 1.89 1.85 Oceania Kimban orogeny: 1.84 1.70 Oceania Cornian ...
This is a list of official and unofficial names for time spans in the geologic timescale and units of chronostratigraphy.Since many of the smallest subdivisions of the geologic timescale were in the past defined on regional lithostratigraphic units, there are many alternative names that overlap.
The geological timeline of Western North America includes significant geological events over millions of years in the evolution of Western North America, including several tectonic plate interactions involving the North American plate and leading to the formation of various mountain ranges and seaways.