Serra da Cangalha is an impact crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 in the State of Tocantins

Tocantins (state)

Tocantins is one of the states of Brazil. . The state was formed in 1988 out of the northern part of Goiás, and construction began on the capital, Palmas, in 1989, in contrast to most of the other cities in the state which date back to the Portuguese colonial period...

, near the border of Maranhão

Maranhão

Maranhão is a northeastern state of Brazil. To the north lies the Atlantic Ocean. Maranhão is neighbored by the states of Piauí, Tocantins and Pará. The people of Maranhão have a distinctive accent...

 State, in northeastern Brazil.

The crater is between 12 and 13 km in diameter, making it the second-largest known crater in Brazil. Its age is estimated to be about 220 million years (Triassic

Triassic

The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...

 period). The name means Pack-Saddle Mountains in Portuguese

Portuguese language

Portuguese is a Romance language that arose in the medieval Kingdom of Galicia, nowadays Galicia and Northern Portugal. The southern part of the Kingdom of Galicia became independent as the County of Portugal in 1095...

.

Description

The outer perimeter is a circular inward scarp about 12 km in diameter on the largely undisturbed Cretaceous

Cretaceous

The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...

 and upper Silurian

Silurian

The Silurian is a geologic period and system that extends from the end of the Ordovician Period, about 443.7 ± 1.5 Mya , to the beginning of the Devonian Period, about 416.0 ± 2.8 Mya . As with other geologic periods, the rock beds that define the period's start and end are well identified, but the...

 sediments of the Parnaíba basin, breached on the west, north, and south sides by drainage valleys. Within the perimeter there is a series of concentric circular valleys and a central basin, all at roughly the same elevation, separated by ring walls. Shuttle Radar Topography Mission

Shuttle Radar Topography Mission

The Shuttle Radar Topography Mission 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 Earth prior to the release of the ASTER GDEM in 2009...

 imagery shows a faint ring about 11 km in diameter, a second ring of gentle hills about 5--6 km in diameter, and an inner ring of steeper hills, about 3 km in diameter and up to 420 m high, open to the northwest, surrounding a central basin about 2.2 km in diameter
.

The impact origin is attested by the presence of impact breccias, quartzite shatter cone

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...

s and shocked quartz

Shocked quartz

Shocked quartz is a form of quartz that has a microscopic structure that is different from normal quartz. Under intense pressure , the crystalline structure of quartz will be deformed along planes inside the crystal...

. The meteorite is believed to have struck the surface at a low oblique angle, 25 to 30 degree

Degree (angle)

A degree , usually denoted by ° , is a measurement of plane angle, representing 1⁄360 of a full rotation; one degree is equivalent to π/180 radians...

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

Carboniferous

The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...

 and Devonian

Devonian

The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...

 periods occur within the crater. A magnetic survey of the structure indicates that deformation within the crater extends to a depth of about 2 km
.

History and studies

The identification of the structure as an impact crater was first published in 1973 by R.S. Dietz

Robert S. Dietz

Robert Sinclair Dietz was Professor of Geology at Arizona State University. Dietz was a marine geologist, geophysicist and oceanographer who conducted pioneering research along with Harry Hammond Hess concerning seafloor spreading, published as early as 1960–1961...

 and B.M. French

.
Shatter cones were reported by Beatty

Beatty

Beatty is a surname of Scottish and Irish origin. In the Scottish case, it is derived from the name Bartholomew, which was often shortened to Bate or Baty. Male descendants were then often called Beatty, or similar derivations like Beattie or Beatey. The name Beatty also arose in Ireland from...

 in 1980.
Impact breccias, impact melting, and shocked quartz were reported by McHone in his 1986 thesis.
A magnetic survey of the structure was published by A.A. Adepelumi and others in 2005.