The Hawaiian saying in the title expresses the animistic sense of stone that has long enriched their culture. More than any other cultural group, within the larger Polynesian culture, the Hawaiians have built upon their perception of stone.
This accessible EarthCache is an opportunity to consider , at close hand , examples of tuff from close to Diamond Head, the volcano down the beach to your left. (Additional image in the "gallery")
"The Stones of Life"
CULTURAL BACKGROUND:
Here you can find the four large stones named Kapaemahu, Kahaloa, Kapuni and Kinohi nestling in a stand of palm trees on a busy street in Kuhio Beach Park.
Near the police substation at Waikiki Beach Center are the four volcanic boulders which are considered sacred and legendary Hawaiian symbols. They are said to contain the mana (spiritual essence) of four māhū (individuals who were both male and female in mind, body and spirit) healers who came to Oʻahu from Tahiti around AD 400.
According to ancient legend, the healers helped the island residents by relieving their maladies. Soon the māhū healers became very famous. As a tribute when the healers left, the islanders placed the four boulders where they had lived.
The two heaviest stones are believed to weigh around eight and ten tons , how the ancients moved them the two miles from a quarry east of Diamond Head remains a mystery.
In 1941 a bowling alley was built on the site and the stones were used in the foundation, despite protests from the local community. After the structure was demolished in 1958, the stones were given some prominence in the newly created Kuhio Beach park.
However, more indignities were to come. They were dug up yet again in 1980, so a sewer line and toilet could be built on the spot. Tourists began using them as a towel-drying rack, sparking many Hawaiian community protests.
In 1997, the stones were moved yet again to their present spot and fenced off.
THIS EARTHCACHE FOCUSES ON BASALT:
Basalt is a common extrusive igneous rock formed by the rapid cooling of lava exposed at or very near the surface of Earth.
More than 90% of all volcanic rock on Earth is basalt, and the eruption of basalt lava is observed around 20 times per year by geologists.
Basalt is a fine grained, opaque durable rock with a medium hardness. It can have a glassy, massive, porphyritic, scoriaceous or vesicular texture.
These variations of basalt that can look quite different from one another. These differences are due to subtle variations in mineralogy, the gas content of the lava, and how the lava cooled. Even small differences in these conditions can have a drastic impact on what basalt looks like.
One of the defining features of basalt’s appearance is its texture. All basalt is fine-grained, meaning that you cannot see the individual crystals in the rock. This texture is known as ‘aphanitic’, and it forms when magma cools rapidly, preventing crystals from having enough time to grow before becoming completely solidified.
The color can vary, black, brown and light to dark grey. Weathered basalt can have a red appearence due to high iron content.
Basalt has a strict chemical definition. Basalt is an igneous rock that contains more than 45 and less than 52% of SiO2 and less than five percent of total alkalies.
Molten basalt lava has a low viscosity due to its relatively low silica content (between 45% and 52%), resulting in rapidly moving lava flows that can spread over great areas before cooling and solidifying.
These large areas are called flood basalt and can cover hundreds of thousands of square kilometers making them the most voluminous of all volcanic formations.
Basalt has amazing forms, depending how it cools, it could be ‘rope like’, ‘pillow‘ , or columnar basalt.
Another variety, scoria , forms when magma containing huge amount of dissolved gas bubbles out from a volcano during an eruption. Sort of like a soda can releasing carbon dioxide when it is opened. Typically it has abundant very small (< 1mm) round bubble-like cavities known as vesicles.
THIS EARTHCACHE SPECIFICALLY:
These four large stones are BASALT from just east of Diamond Head. The volcano cone consists of beds of palagonitized subaerial brown tuff containing much accessory and accidental ejecta, including appreciable amounts of reef limestone and occasional fragments of Koolau basalt. Some contains vegetation molds and carbonized remains of land plants including myrtaceous plant resembling EUGENIA.These are the most common "fossils" in Hawaiian basalt. They are hollow casts of trees formed when flowing lava encases them, and the wood then rots away.
Inclusions, also called xenoliths, are fragments of one rock type enclosed within another. Hawaii is formed by volcanic activity that originates from the mantle, ie. deep within the earth. The basaltic magma erupts and carries fragments from the mantle with it, not USUALLY from the crustal rocks that might contain limestone. While you might find limestone in other environments or as surface deposits in Hawaii, the inclusions found within Hawaiian basalt are mostly ultramafic xenoliths from the mantle, and not limestone. An ultramafic xenolith is a fragment of mantle rock, composed primarily of DARK COLORED magnesium-rich minerals like olivine and pyroxene, that is caught by and carried up to the Earth's surface within another, more molten rock
However the presence of "fossil plant remains", and fact that basalt unit rests on a massive LIGHTER COLORED limestone reef 20 feet above sea level indicates eruption during the late Pleistocene.
However, if limestone xenoliths were present, they would suggest assimilation of crustal carbonate rocks by the rising magma, which is a process that occurs in other volcanic settings but has not been documented as a primary xenolith type in Hawaii.
This magma is nepheline basalt. Included in middle part of Honolulu volcanic series which underlies Kaimuki basalt in Kapakulu Quarry and Black Point basalt near Kupikipikio Point (Black Point).
LOGGING REQUIREMENTS
Look at the four large stones:-
- WHAT VARIETIES OF BASALT DO YOU SEE HERE? Say how you distinguished them.
- DO YOU SEE ‘VESICLES? If so, are all the bubbles the same size?. Comment on their size.
- WHAT IMPACT WOULD MANY VESICLES HAVE ON THE WEIGHT OF THE STONES? THINK ABOUT THE CHOICE OF STONES AND THEIR TRANSPORTATION?
- IS THERE ANY SUBSTANTIVE DIFFERENCE BETWEEN THE TEXTURES OF THE STONES? ((use the Hawaiian name for any stones you wish to highlight))
- THERE ARE ‘INCLUSIONS’ IN THE BASALT. DESCRIBE ANY YOU SEE. HOW ARE THESE DIFFERENT FROM THE ROCK MASS? ANY SUGGESTIONS AS WHAT THEY MIGHT BE?
- YOU MUST EITHER TAKE A PHOTO OF YOURSELF OR A PERSONAL ITEM LOOKING TOWARDS THE CLOCK - ( away from the monument to avoid spoilers) -AND INCLUDE IT IN YOUR LOG
You should send your logging task answers preferibly through the message centre
Then feel free to log this EarthCache immediately.
You need to submit answers INDIVIDUALLY. Group responses will not be accepted.
Please don’t include the answers in your log even in an encrypted form.
Complete responses to the logging tasks are required including a photo in your log.
TAKE LOTS OF PHOTOS IF YOU WANT, BUT PLEASE DO NOT POST PHOTOS THAT SPOIL THE GAME !
Sources / Acknowledgments
☆☆☆ FTF honours to _Skotlee_ ☆☆☆