Sediment Analysis labPart II

Hawaiian Mystery Sands

Use the following info to

• Help you identify from which of the following 6 beaches the “mystery” samples came

• Help you explain what characteristics (composition, grain-size, etc.) of the mystery samples helped you identify its beach.

Beach 1: Kaihalulu Beach

Photo: Kevin Coates, Hana Kayak Tours

The distinctive red sand of Kaihalulu Beach (near Hana on Maui’s eastern end)

comes from the high iron oxide (rust) content in the volcanic cinders of nearby

Ka‘uiki Hill.

Image by Dennis Kunkel courtesy of Bishop Museum

Beach 2: Kailua Beach

Photo: David Kemble

The fine white sand of Kailua Beach on the windward coast of O‘ahu is made from broken down bits of coral reef and marine

shells and skeletons. In the shelter of a broad fringing reef, this beach’s gentle

waves make it a favorite for family recreation.

Image by Dennis Kunkel courtesy of Bishop Museum

Beach 3: Kalapana Beach

Photo: John Bortniak,National Oceanic & Atmospheric Administration,

Dept. of Commerce

Broken down bits of lava rock form the famous black sand beaches on the southeast coast of the

island of Hawai‘i. As hot lava from Kilauea and Mauna Loa pours into cool ocean water, steam

explosions blast the lava apart, forming fine grains of basalt rock sand.

Image by Dennis Kunkel courtesy of Bishop Museum

Beach 4: Papakulea Beach

Photo: Richard A. Cooke III

The famous green sand of Papakulea Beach near the South Point of the island of Hawai‘i comes

from olivine, a common mineral found in volcanic rocks. This side of the island is too young to have

developed coral reefs, so recent lava flows are the only source of sand.

Image by Dennis Kunkel courtesy of Bishop Museum

Beach 5: Sandy Beach

Photo: David Kemble

Bits of broken reef combined with eroded lava rock from nearby Koko Crater form the sand on Sandy Beach, a popular bodysurfing spot on the southeastern tip of O‘ahu. The relentless waves and strong current constantly break down new material. They carry away the fine sand grains,

leaving coarse sand.

Image by Dennis Kunkel courtesy of Bishop Museum

Beach 6: Sunset Beach

Photo: David Kemble

A wide variety of materials and organisms dislodged from the surrounding reefs form the sand at Sunset Beach on the North Shore of O‘ahu. This calm summer beach transforms

into a surfing beach in the winter, when huge waves pulverize the reef and its attached

animals.

Image by Dennis Kunkel courtesy of Bishop Museum