Alice Springs Orogeny
Encyclopedia
The Alice Springs Orogeny was a major tectonic
(mountain building) episode in central Australia
responsible for the formation of a series of large mountain ranges. The episode started at about 450 million years ago and concluded about 300 million years ago. The orogeny
was centred in an area that had previously been a marine sedimentary basin
, and involved the thrusting up of the underlying metamorphic
and igneous
rocks of Proterozoic
age. Sediment was eroded off the rising mountain belt to become incorporated into the remaining relics of the former sedimentary basin, becoming the Amadeus
, Georgina
and Ngalia
basins that are preserved today. Ultimately all the sedimentary rocks in these basins became folded
to become part of the growing mountain ranges. Today we see only the eroded remnants of these former mountains in the MacDonnell Ranges
and other ranges throughout much of central Australia.
Tectonics
Tectonics is a field of study within geology concerned generally with the structures within the lithosphere of the Earth and particularly with the forces and movements that have operated in a region to create these structures.Tectonics is concerned with the orogenies and tectonic development of...
(mountain building) episode in central Australia
Central Australia
Central Australia/Alice Springs Region is one of the five regions in the Northern Territory. The term Central Australia is used to describe an area centred on Alice Springs in Australia. It is sometimes referred to as Centralia; likewise the people of the area are sometimes called Centralians...
responsible for the formation of a series of large mountain ranges. The episode started at about 450 million years ago and concluded about 300 million years ago. The orogeny
Orogeny
Orogeny refers to forces and events leading to a severe structural deformation of the Earth's crust due to the engagement of tectonic plates. Response to such engagement results in the formation of long tracts of highly deformed rock called orogens or orogenic belts...
was centred in an area that had previously been a marine sedimentary basin
Sedimentary basin
The term sedimentary basin is used to refer to any geographical feature exhibiting subsidence and consequent infilling by sedimentation. As the sediments are buried, they are subjected to increasing pressure and begin the process of lithification...
, and involved the thrusting up of the underlying metamorphic
Metamorphic rock
Metamorphic rock is the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form". The protolith is subjected to heat and pressure causing profound physical and/or chemical change...
and igneous
Igneous rock
Igneous rock is one of the three main rock types, the others being sedimentary and metamorphic rock. Igneous rock is formed through the cooling and solidification of magma or lava...
rocks of Proterozoic
Proterozoic
The Proterozoic is a geological eon representing a period before the first abundant complex life on Earth. The name Proterozoic comes from the Greek "earlier life"...
age. Sediment was eroded off the rising mountain belt to become incorporated into the remaining relics of the former sedimentary basin, becoming the Amadeus
Amadeus Basin
The Amadeus Basin is a large intracratonic sedimentary basin in central Australia, lying mostly within the southern Northern Territory, but extending into the state of Western Australia. It is named after Lake Amadeus which lies within the basin...
, Georgina
Georgina Basin
The Georgina Basin is a large intracratonic sedimentary basin in central and northern Australia, lying mostly within the Northern Territory and partly within Queensland. It is named after the Georgina River which drains part of the basin. Deposition of locally up to ca...
and Ngalia
Ngalia Basin
The Ngalia Basin is a small intracratonic sedimentary basin in central Australia, lying within the southern Northern Territory. Deposition of locally up to about six km of marine and non-marine sedimentary rocks took place from the Neoproterozoic to the late Paleozoic...
basins that are preserved today. Ultimately all the sedimentary rocks in these basins became folded
Fold (geology)
The term fold is used in geology when one or a stack of originally flat and planar surfaces, such as sedimentary strata, are bent or curved as a result of permanent deformation. Synsedimentary folds are those due to slumping of sedimentary material before it is lithified. Folds in rocks vary in...
to become part of the growing mountain ranges. Today we see only the eroded remnants of these former mountains in the MacDonnell Ranges
MacDonnell Ranges
The MacDonnell Ranges of the Northern Territory, are a long series of mountain ranges located in the centre of Australia , and consist of parallel ridges running to the east and west of Alice Springs...
and other ranges throughout much of central Australia.