Adams Seamount facts for kids

Adams Seamount, also known as Forty Mile Reef, is an underwater volcano. It is located in the central Pacific Ocean. This seamount is about 100 kilometers (62 miles) southwest of Pitcairn Island. It sits above a special place called the Pitcairn hotspot.

What is Adams Seamount?

Adams Seamount is part of a group of about 90 underwater mountains. These mountains are found about 90 kilometers (56 miles) east-southeast of Pitcairn Island. Adams is the largest of these seamounts. Another big one nearby is called Bounty Seamount. Most of the other seamounts are smaller, less than 0.5 kilometers (0.3 miles) tall. Scientists discovered these seamounts in 1989 using a research ship called the RV Sonne.

How Big is Adams Seamount?

Adams Seamount is shaped like a cone. It rises 3,500 meters (11,500 feet) from the ocean floor. Its top is only about 39 meters (128 feet) below the surface. The base of Adams Seamount is about 30 kilometers (19 miles) wide. It has two peaks at its top.

Scientists have found coral and sand made from coral on Adams Seamount. Because it is so tall, Adams Seamount was probably an island during the Last Glacial Maximum. This was a time when sea levels were much lower.

What is it Made Of?

The sides of Adams Seamount are covered with fresh lava flows. You can also find volcanic rocks and debris there. Some of the lava flows have features like aa lava and lava tubes. Deeper parts of the seamount are covered with small volcanic rocks called lapilli and scoria. Smaller volcanic cones and mounds can be seen on its slopes.

How Adams Seamount Formed

Adams Seamount and the other nearby seamounts were created by the Pitcairn hotspot. A hotspot is a very hot spot deep inside the Earth. It melts rock, which then rises to the surface as lava. The Pitcairn hotspot is one of several hotspots in the Pacific Ocean. Other famous ones include the Hawaii hotspot. These seamounts grew from the ocean floor, which is about 30 million years old.

Scientists have studied rocks from Adams Seamount. They found types of volcanic rock like Alkali basalt and trachyte.

When Did it Erupt?

The rocks found on Adams Seamount look very fresh. This means the seamount has been active recently. Scientists used a method called potassium-argon dating to find the age of the rocks. They found that some rocks are from the Holocene period. This means they are only a few thousand years old. For example, one rock was about 3,000 years old. Other rocks were between 4,000 and 7,000 years old. Unlike Bounty Seamount, Adams Seamount does not have active hot water vents.

Life Around Adams Seamount

Adams Seamount is home to a coral reef. This is one of the deepest tropical coral reefs in the world. The reef is mostly made of Pocillopora sp. and Porites deformis corals. Many different kinds of reef fish and sharks also live there. People from Pitcairn Island use Adams Seamount as a place to fish. Adams Seamount is an important part of the Pitcairn Islands Marine Reserve.