The Fenambosy Chevron is one of four chevron-shaped land features

Chevron (land form)

A chevron is a wedge-shaped sediment deposit observed on coastlines and continental interiors around the world. The term chevron was originally used independently by Maxwell and Haynes and Hearty and others for large, v-shaped, sub-linear to parabolic landforms in southwestern Egypt and on islands...

 on the southwest coast of Madagascar

Madagascar

The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...

, near the tip of Madagascar, 180 metres high and 5 km inland. It is composed mainly of material found on the ocean

Ocean

An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...

. Chevrons such as Fenambosy have been hypothesized as providing evidence of "megatsunami

Megatsunami

Megatsunami is an informal term to describe a tsunami that has initial wave heights that are much larger than normal tsunamis...

s" caused by comet

Comet

A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...

s or asteroid

Asteroid

Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...

s crashing into Earth

Earth

Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

. About 900 miles southeast from the Madagascar chevrons, in deep ocean, is Burckle crater

Burckle Crater

Burckle Crater is a hypothesized undersea crater that has been proposed by the Holocene Impact Working Group. They considered that it likely was formed by a very large scale and relatively recent comet or meteorite impact event...

, which Dallas Abbott

Dallas Abbott

Dallas Abbott is a research scientist at the Lamont-Doherty Earth Observatory of Columbia University and is part of the Holocene Impact Working Group. The primary focus of her present research is on submarine impact craters and their contribution to climate change and megatsunamis...

 discovered in 2005. Although its sediment

Sediment

Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....

s have not been directly sampled, cores from the area contain high levels of nickel

Nickel

Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...

and magnetic components associated with impact ejecta. Burckle crater has not been dated, but Abbott estimates that it is 4,500 to 5,000 years old.