Throughout human history, stones have always been our important partners. Stone as a memory of the earth. Each piece records the history of the earth, from the surging of lava to the movement of glaciers, from the reproduction of living things to changes in the climate. They are witnesses of time and tellers of history.
For example, meteorites are fragments of solid matter that fly from space to Earth. They bring information from outer space and give us a glimpse into the mysteries of the universe. "Meteorites provide us with a unique perspective that allows us to explore the origin and evolution of the universe. Another example is obsidian, which is found in areas with high volcanic activity. Not only is it an important clue to our understanding of volcanic activity, but it also reveals the forces surging deep in the earth. "The formation of obsidian is a chronicle of the Earth, giving us a glimpse into the inner workings of the Earth.
obsidian
Chen-shi-hsien
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And how are stones formed?
In the late 18th century, early naturalists were influenced by the Genesis view and the legend of Noah's flood. Early scholars such as Giovanni Arduino tried to classify all the rocks they observed as oversimplified sequences of hard crystalline "primary" rocks (metamorphic rocks such as granite and schist/gneiss) and believed that they all formed at the same time as the Earth. These rocks, in turn, are covered by "secondary rocks", which are fossil-rich, often folded or deformed sedimentary rocks (we now know that most of the "secondary rocks" are dated between the Devonian and Cretaceous periods). According to some naturalists, the "secondary" rock formations were the main sediments of the time of Noah's Great Flood. The 'secondary' layers are overlain loose sediments and sedimentary rocks, known as 'tertiary rocks' (Tertiary strata), which are thought to have formed after the Great Flood.
If you hadn't gone outside to see real rocks up close, you might have accepted this overly simplistic classification of rocks. But most geologists at the time did not have the opportunity to look elsewhere and could not verify whether their knowledge of outcrops was correct, and their preconceived dogmas forced explanations for the limited rocky outcrops in northern Europe. This view that all rocks were formed in water (often interpreted as Noah's Flood) is known as "neptunism." Hydrologists believe that even lava flows have been in the water. Others, however, argue that lava flows were once hot molten rock, rather than from water, a view known as "plutonism."
The most famous aquamorphist was the German naturalist Abraham Gottlob Werner. Werner is a professor of mineralogy at the School of Mines in Freiburg. It is said that he lectured with great humor and a very personal style, and almost everyone who listened to his lectures became his followers. Werner's ideas were popular in Europe, largely due to his eloquence and charisma, rather than to a detailed examination of large outcrops (although, contrary to the prevailing view at the time, he did not explicitly identify sedimentary rocks and lava flows as products of Noah's Flood, only that they formed in water). His followers can be found at major European universities, including the University of Edinburgh. Robert Jameson of the University of Edinburgh was a staunch aquarist and James Hutton's main rival. Even the great poet and naturalist Goethe was a firm believer in the theory of water. In the fourth act of Faust, there is a dialogue between the aquaticists and the pyrotheists, in which Mephistopheles (the devil in Faust) is apparently the spokesperson for the evil pyromorphist view.
Abraham Gottlob Werner
One might ask, "How can anyone think that volcanic rocks form in water?" Let's not forget that chemistry was still in its infancy at the time, and no one knew that the melting of rocks was related to temperature and pressure. In Europe, too, almost no one has ever seen a lava flow. Nowadays, we usually see videos of hot lava flowing from active volcanoes such as Kilauea; But in Hutton's time, few Europeans traveled far from home. Unless someone happens to be traveling to southern Italy during the eruptions of Vesuvius, Stromboli or Etna, there is no chance of seeing volcanic eruptions, and the main product of these volcanoes is ash, not lava flows. In 1774, the French geologist Nicolas de Marré pointed out that the volcanic cones and weathered lava flows of the extinct volcanic complex in the Auvergne region of southern France indicated that it had once erupted as an active volcano. This evidence alone is sufficient to prove the existence of the theory of igneous formation, although for a long time the theory of hydration was dominant.
As James Hutton pondered the elevation and erosion of mountains, he became convinced that granitic and basaltic lava flows were formed by red-hot molten rocks known as magma, rather than in water. However, there were no active volcanoes in Northern Europe at the time, and Hutton had never seen a lava flow on the ground. Due to the lack of evidence, Hutton set out to look for outcrops where granite or basalt melted or intruded into the original rocks altered the surrounding rock.
James Hutton
Soon after, he discovered that the gravel of the River Tilt, which flows south from the Cairngorm Mountains in Edinburgh's northern highlands, was littered with granite pebbles and ancient metamorphic rocks. From this, he deduced that there must have been these two types of rocks in the riverbed, and that an investigation upstream might have led to the junction of the two. One day in 1785 he made his way up the Tilt Gorge and spent the night at Forest Lodge. The next day he surveyed the exposed rocks in the bed of the Tilt River upstream of the Dail-an-eas bridge near the Lodge Forest, and discovered what he had been looking for: brick-red granite cut through the older metamorphic rocks and altered the surrounding rocks (this field "cut-through" relationship is still used in geology today to determine how early or late the rocks formed). Not only that, but granite must have been older than metamorphic rocks, which means that not all rocks were formed at the beginning of the earth's formation.
The granite discovered by Hutton pierced through the schists
But Hutton needed stronger evidence: signs of lava flows intruding into layered sedimentary rocks formed in the water. Hutton walks through the hills south of Edinburgh and discovers the mountain range towering over the city – Arthur's Seat (the throat of an ancient volcano in Arhur's seat); On the north side of the range, the Salisbury Crag is a cliff jutting out of ancient volcanic rock. Eventually, he found what he was looking for on the southwest slope of the cliff: basalt lava intruding into sedimentary rock layers and deforming the sedimentary rocks. This place is now so famous that it is known as the "Hutton's Section". In the course of teaching many geology courses, teachers will regularly bring students here for field trips and internships. Later, Hutton found similar profiles in Galloway and Arran Island.
Hutton Profile
Hutton, along with chemist friends such as Joseph Black and Sir James Hall, also knew far more about the chemical composition of rocks than their contemporaries. Hutton knew what minerals (such as salt) formed by precipitation from water by chemical action were like, and therefore knew that magma was not formed in water. In 1768, Hutton moved to Edinburgh to work with Blake, both of whom shared a love for chemistry, which is key to understanding the effects of high temperatures on rocks. Black deduced the presence of latent heat (the amount of heat absorbed or emitted during the phase transition of a substance, such as solid-liquid, liquid-gas, solid-gas, and solid-gas) and the important influence of pressure on the melting point of a substance. For example, when water is heated at a certain pressure, it remains liquid even though the heating temperature is above the boiling point. The understanding of heat and pressure became key to Hutton's study of how buried sediments turned into rock. In 1792, Hall did an experiment. He heated a piece of basalt to between 800~1200 °C, and then slowly cooled it, as a result, the rock recrystallized into basalt. This is the earliest geological experiment that shows what molten rock looks like in nature. This was a strong support for the igneous school, which also led to the creation of experimental petrology, and the "igneous theory of rocks" was formed.
Hutton believed that the center of the Earth was hot and molten, powered by what he called the "Earth Heat Engine." He once said: "Volcanoes do not exist to intimidate superstitious people, nor to immerse them in piety and devotion." It should be seen as a vent for the furnace. "This heat engine causes the earth's crust to uplift and mountains to uplift, which in turn are weathered and eroded into sediment. The sediment then enters the sea with the current. Uplifting, erosion, sedimentation, and re-uplifting, these processes go on and on, never stopping. All of these ideas are part of the dynamic earth theory. The theory is that the Earth is very old and constantly being reshaped and recycled, rather than a young planet that has remained unchanged since its inception 6,000 years ago.
Hutton's essay was published in 1788, as was his book A Theory of the Earth in 1795. Since then, his views have spread around the world. However, Hutton's ideas were not immediately accepted by the general public, in part because his writings were obscure and difficult to read and understand. When Hutton died in 1797, his theories were still not widely accepted. Until a young man named Zars Ryle appeared, who was born in 1797, the year Hutton died. He initially studied law with the ambition to become a lawyer, but soon got bored and turned to the emerging geology as a hobby. Ryle traveled all over Europe and observed many geological phenomena with the eyes of Hutton's uniformity. Eventually, Ryle completed his masterpiece, Principles of Geology, which was published in three volumes between 1830 and 1833. Written in a manner similar to a lawsuit summary, the book collates all the observations he has gathered during his travels and readings, and uses the skills of a lawyer to make the definitive conclusion of the planetary varianguis. Like many good lawyers, he used a variety of tactics to undermine the credibility of catastrophists while providing strong evidence for his own views. He proposed accounts of volcanic eruptions or hydrothermal vents in several places, especially in southern Italy, confirming Hutton's theory of the "thermal engine of the earth". Within a few years, the last conservative catastrophists and hydrologists died or gave up, and geology finally became a modern science.
Principles of Geology
Of course, from today's point of view, the theory of hydrogenesis and igneous theory have their own correctness: the theory of hydratogenesis explains the origin of fossils and the arrangement of strata to a certain extent, but overemphasizes the "power of God" of nothingness, and tries to make up for it through speculation when the evidence is insufficient; During the evolution of the earth, the thermal energy inside the earth is the main energy that causes geological processes, while the external energy mainly comes from solar radiation energy. From this point of view, the pyrotechnic theory is more advantageous. At the same time, the theory of hydraulicism emphasizes the suddenness of flood occurrence and formation of strata, and the theory of igneous formation emphasizes the continuity of volcanic and magmatic processes, and the two are intertwined with the "homogeneous theory" and "catastrophic theory", and from this point of view, there is a certain one-sidedness between the two.
But the dedication to truth and the unwavering pursuit of science, such as Hutton and Ryle, even after hundreds of years of dust, still shine like the sun and guide us to higher mountains.
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