Igneous Rocks and Plate Tectonics
Presentation on theme: "Explain the relationship between igneous activity, magmatic composition, rock types and plate boundaries."— Presentation transcript. Most igneous activity is a result of plate tectonics, plate shifting. THere is an exception- the hot spots such as the Hawaiian Islands and. We don't generally see this volcanic activity, however, because the ocean hides most of it beneath a blanket of water. Mid-ocean ridge volcanoes, which develop .Igneous rocks and plate tectonics
Increased T as the plate sinks deeper. Also the plate is saturated in water. The melting oceanic crust is basic so what kind of magma will form when it melts?
More SiO2 rich and so will move towards being intermediate. This magma will move upwards through the overlying mantle and thin crust to the surface. Then what will happen?
Igneous Rocks and Plate Tectonics
What will the products be: Lavas will be as important as pyroclastics. So what will happen to the magma over time feeding a particular volcano? It will become more SiO2 rich. What will that do to the style of eruptions? Plutonic intrusions that form deep down in batholiths. What will be the crystal size? They will tend to be intermediate so what will the rock be? What will their crystal size be? So what will the rock type be?
When the debris settled, it blanketed an area of 2, square km with tuffs that, in the park, reached a thickness of m. Flood-Basalt Eruptions Flood basalt layers exposed on the wall of a canyon in Idaho.
What is the relationship between igneous activity and plate tectonics? | Yahoo Answers
The aggregate volume of rock in such a plateau may be so great overkm3that geologists also refer to the region as a large igneous province LIP. The basalt here, which erupted around 15 million years ago, reaches a thickness of 3. Eventually, basalt covered an area ofkm.
Iceland is one of the few places on Earth where mid-ocean ridge volcanism has built a mound of basalt that protrudes above the sea. The island formed where a hot spot lies beneath the Mid-Atlantic Ridge the presence of this hot spot probably due to an underlying mantle plume means that far more magma erupted here than beneath other places along the ridge.
Because Iceland straddles a divergent plate boundary, it is being stretched apart, with faults forming as a consequence. This rift is the trace of the Mid-Atlantic Ridge. Faulting cracks the crust and so provides a conduit to a magma chamber. Not all volcanic activity on Iceland occurs sub-aerially. Some eruptions take place under glaciers and melt large amounts of ice.
Volcanic Explosions to Remember Explosions of volcanoes generate enduring images of destruction.
Helens, a snow-crested stratovolcano in the Cascades of the north-western United States, had not erupted since However, geologic evidence suggested that the mountain had a violent past, punctuated by many explosive eruptions.
On March 20,an earth quake announced that the volcano was awakening once again. A week later, a crater 80 m in diameter burst open at the summit and began emitting gas and pyroclastic debris.
Their concern that an eruption was imminent led local authorities to evacuate people in the area. The climactic eruption came suddenly.
As these plates float around, they interact with each other.
What is the relationship between igneous activity and plate tectonics?
They can either get closer together or drift apart, and this tectonic plate movement gives us the right conditions for the formation of igneous rocks. What's the difference between an active and passive continental margin? Diverging Tectonic Plates and Igneous Rocks Let's take a look at igneous rock formation where tectonic plates move apart or diverge.
As these massive plates of the earth's crust slowly separate from each other, magma from below the crust has an opportunity to squeeze up through the gap and reach the surface. This can even happen if the boundary between plates is found at the bottom of the ocean.
In fact, diverging tectonic plates are responsible for the formation of the Mid-Atlantic Ridge, which is a continuous mountain chain located under the surface of the sea. As the magma makes its way through the opening created by the diverging plates, the magma meets up with the cooler temperatures, allowing it to solidify into igneous rock. Converging Tectonic Plates and Igneous Rocks Igneous rocks can also form where plates bump up against each other.