Hawaiite

Classification：Igneous Rock

Volcanic rocks similar to basalt are relatively high in basalt and relatively shallow in color. They are a kind of Na content basalt.

Hawaiite is an alkaline basalt containing feldspar.

Essential information：
Hawaiite is a dense or foam like rock solidified by the cooling of volcanic magma. It belongs to magmatic rock (also known as Huo Chengyan) in rock classification of geology. The magma temperature of the eruption is up to one thousand and two hundred Baidu. With a certain viscosity, the magma flows slowly when the ground is flat, and the flow is only a few meters per minute, and the speed is greatly accelerated when it meets the steep slope. During its flow, it carries a lot of water vapor and bubbles. After cooling, it forms various variant shapes. Hawaiite was originally defined as a variety of olivine basalt, of which the standard mineral feldspar is feldspar or medium feldspar. The term derives from the name of Hawaii and named .

Main components:
The main components of Hawaiite are silica, three oxidation two aluminum, iron oxide, calcium oxide, Magnesium Oxide (and a small amount of potassium oxide, sodium oxide), of which the content of silica is the most, accounting for about forty-five percent to fifty.

Color:
The color of Hawaiite is mostly black. Due to its dense texture, its specific gravity is heavier than that of general granite, limestone, Sha Yan and shale.

Cause:
The columnar joint in Hawaiite -- in Hawaiite lava flow, the vertical condensation surface often develops into regular six square columnar joints.

It is generally assumed that there is a homogeneous distribution of cooling centers in the homogeneous base of the lava (the distribution of equilateral triangle, the distance of the cooling center equal to each other), and then the isotropic center contraction, forming a six square columnar joint.

Hawaiite is formed by the crystallization of Hawaiite pulp. It is inferred that the basalt magma in Hawaii, USA is directly from 60~90 kilometers underground, and often carries the deep source xenoliths, the basic composition of the upper mantle, that is, the composition of the two pyroxene peridotite. Therefore, the Hawaiite pulp originates from the upper mantle.

Use:
The main minerals are related with the Hawaiite of copper, iron, titanium, vanadium, cobalt, Iceland etc.. Some olivine, pomegranates, and megalite from the basalts are related to the deep enclaves of the two peridotite in Hawaiite, and they can be used as gemstones. In addition, some Hawaiite are ideal raw materials for cast stone, rock wool and lime. Pozzolanic fertilizers can be used as fertilizer, and mineral water related to volcanic activities can be used for medical purposes.

Relevant information:
Sina global geographic news (June 2nd) Beijing time news, according to the National Geographic website, the traditional view that the Hawaii volcano island is formed by a hot rock plume through the core of the earth's hot rock, which is still "feeding" to the volcanic island. For this traditional viewpoint, a new study finds challenges. American scientists say they have found solid evidence that there is a huge hot rock below the Hawaii sea bed, but it is not a mantle plume that extends from the earth's core to the surface. This huge hot rock area is hundreds of kilometers from the nearest Hawaii island.

Until now, researchers still expressed the lack of ideal seismic data in this area, so it is difficult to question this traditional interpretation. The traditional view is that the hot rock flow around the core forms the 3100 mile (5000 km) long island chain and seabed mountain in the Pacific Ocean.
According to the traditional view, as the crust slid over the mantle plume - as if on the conveyor belt - the seabed sprayed lava, and during the tens of millions of years of change, the cooling lava layers formed mountains and islands. Geologists say, after analyzing 20 years of seismic data, they found a 800 - mile (1300 - kilometer) - wide hot rock area in the Hawaii area, which is located below the big island. The island is the youngest islands of Hawaii Island, the traditional view is that it is located in the upper mantle plume.

Robert Van Del Hiester, a geologist and research author at the Massachusetts Institute of Technology, said: "although the new evidence has questioned the giant mantle plume theory, we can not exclude the possibility of a narrow mantle plume below the island. The main source of the mantle plume is located in another area, not directly connected below. This research is led by Van Del Hiester and his colleague Cao Qin (Qin Cao), and his research papers are published in the online edition of science.

Volcanoes are formed at the junction of the mantle (the largest thickness of the earth) and the melting outer core. The outer core is about 1800 miles underground (about 2900 kilometers). The outer core heated the bottom rock of the mantle and made it into buoyant ash, and the mud rushed to the upper part of the earth's crust, just like a lava lamp. Within a few kilometers of the earth's crust, the rock loses pressure and melts, and often erupts in the form of mortar.

Seismic X-ray tomography uses sound and echoes from seismic waves to detect a mantle plume or a hot zone, but the data on Hawaii are very limited. Van Del Hiester said, "mapping the mantle beneath the Hawaii is very difficult, because this area is too far from the large-scale seismic sensor network." It is possible to prove that the data of mantle plumes below the Grand Island are very limited. These data are based on very limited seismic wave sampling. In contrast, the new research analyzed the 20 years' seismic data, and finally found a subtle and clear signal.

These signals point to a huge irregular area of about 410 miles underground (about 660 kilometers): a disc rock area that is 300 to 400 degrees Celsius higher than the surrounding area, between 370 miles (600 kilometers) to 1000 miles (about 1600 kilometers) from the west of the big island. The research team believes that the mantle plume converges at the junction of the upper mantle and the lower mantle, and then meanders toward the crust below the archipelago, which finally flows out of the Hawaii volcano island. Van Del Hiester points out that more evidence is needed to determine what factors form the Hawaii island chain, but the study has at least proved that "our planet is more complex than we thought it was before." Besides, it helps to explain how other Pacific seamounts come into being.