Post by Lorenzo Luciani

BREISLAK PART 7 The manual unfolds through a systematic analysis of the Earth's crust, divided into macro-themes. Breislak harshly attacked the Neptunism of Abraham Gottlob Werner (1749-1817) and experimentally demonstrated that granites and basalts are formed by the cooling of a molten mass to extremely high temperatures (Plutonism). His criticisms in the manual were based on three scientific pillars. Werner claimed that basalt was a marine sedimentary rock. Breislak, who had studied Vesuvius and the Phlegraean Fields for years, demonstrated in the manual the exact chemical and morphological identity between ancient basalts and fresh lava flows. He demonstrated that basalt was not a marine sediment, but molten rock that flowed from a volcano and then solidified. Breislak posed a logical and devastating question to the Neptunists: if the primordial ocean was so deep that it covered the highest mountains to deposit granite, where did all that water go today? Against the idea that granite was the first rock crystallized from water, Breislak presented microscopic and structural evidence to demonstrate that large granite crystals could only have formed through the extremely slow cooling of a magma mass under extremely high pressure underground. Despite his harsh attack on Werner, Breislak demonstrated his scientific maturity by not falling into the opposite extreme, like the radical Plutonism of James Hutton (1726–1797), who attributed almost everything to fire. Breislak proposed a balanced synthesis. He acknowledged Werner's correctness in asserting that limestones, clays, and fossil-rich stratified terrains had indeed formed underwater through sedimentation. He clearly divided the Earth into rocks of aqueous origin and rocks of igneous origin, introducing concepts that anticipate the modern understanding of the rock cycle and metamorphism. Breislak identified three main ways in which rocks transition from one state to another or interact in space. Primitive igneous rocks such as granites or basalts, once exposed to atmospheric agents, rain and rivers, undergo continuous chemical and mechanical alteration. The eroded fragments are transported by water into marine or lake basins where they settle, compact, and transform into sedimentary rocks, such as sandstone. In this way, igneous matter becomes the basis for the formation of aqueous rocks. Observing the terrain of Campania and Veneto, Breislak described the contact points where molten magma, rising toward the surface, touches and passes through layers of already existing sedimentary rocks. The scientist noted that in this boundary zone, the sedimentary rock appears profoundly modified, hardened and recrystallized by extreme heat, losing its original appearance and fossils. This phenomenon is the scientific ancestor of what we now call contact metamorphism.