Serra da Cangalha is an
impact crater
An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact crater ...
in the State of
Tocantins
Tocantins () is one of the 26 states of Brazil. It is the newest state, formed in 1988 and encompassing what had formerly been the northern two-fifths of the state of Goiás. Tocantins covers and had an estimated population of 1,496,880 in 20 ...
, near the border of
Maranhão
Maranhão () is a state in Brazil. Located in the country's Northeast Region, it has a population of about 7 million and an area of . Clockwise from north, it borders on the Atlantic Ocean for 2,243 km and the states of Piauí, Tocantins and ...
State, in north/northeastern Brazil.
The crater is between in diameter, making it the second-largest known crater in Brazil.
Its age is estimated to be about 220 million years (
Triassic
The Triassic ( ) is a geologic period and system (stratigraphy), system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Year#Abbreviations yr and ya, Mya), to the beginning of the Jurassic Period 201.36 ...
period).
[ The name means ''Pack-Saddle Mountains'' in ]Portuguese
Portuguese may refer to:
* anything of, from, or related to the country and nation of Portugal
** Portuguese cuisine, traditional foods
** Portuguese language, a Romance language
*** Portuguese dialects, variants of the Portuguese language
** Portu ...
.
Description
The outer perimeter is a circular inward scarp about in diameter on the largely undisturbed Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...
and upper Silurian sediments of the Parnaíba basin,Shuttle Radar Topography Mission
The Shuttle Radar Topography Mission (SRTM) is an international research effort that obtained digital elevation models on a near-global scale from 56°S to 60°N, to generate the most complete high-resolution digital topographic database of Ea ...
imagery shows a faint ring about in diameter, a second ring of gentle hills about in diameter, and an inner ring of steeper hills, about in diameter and up to high, open to the northwest, surrounding a central basin about in diameter.shatter cone
Shatter cones are rare geological features that are only known to form in the bedrock beneath meteorite impact craters or underground nuclear explosions. They are evidence that the rock has been subjected to a shock with pressures in the rang ...
s and shocked quartz
Shocked quartz is a form of quartz that has a microscopic structure that is different from normal quartz. Under intense pressure (but limited temperature), the crystalline structure of quartz is deformed along planes inside the crystal. These pl ...
. The meteorite is believed to have struck the surface at a low oblique angle, 25 to 30 degree
Degree may refer to:
As a unit of measurement
* Degree (angle), a unit of angle measurement
** Degree of geographical latitude
** Degree of geographical longitude
* Degree symbol (°), a notation used in science, engineering, and mathematics
...
s on dry land. Radial faults are present inside the crater, and some extend up to 16 km from the center.[
Disturbed and steeply inclined sediments from the Carboniferous and Devonian periods occur within the crater. A magnetic survey of the structure indicates that deformation within the crater extends to a depth of about .]
History and studies
The identification of the structure as an impact crater was first published in 1973 by R.S. Dietz and B.M. French.
See also
* Riachão Ring
* Santa Marta crater
References
{{Impact cratering on Earth
Impact craters of Brazil
Triassic impact craters
Landforms of Tocantins
Geology of Brazil