The rivers then carry the ions on to the sea. In the ocean the sodium ions combine with bicarbonate ions to form calcium carbonate. In the ocean most of the calcium carbonate is made by shell-building (calcifying) organisms and plankton. After the organisms die they sink to the seafloor. Over time layers of shells and sediment are cemented together and turn rock, storing the carbon in rock – limestone and its derivatives.
Instead, they are nourished by symbiotic bacteria that also produce energy from methane, similar to their relatives that form mats. Chemosynthetic bivalves are prominent constituents of the fauna of cold seeps and are represented in that setting by five families: Solemyidae, Lucinidae, Vesicomyidae, Thyasiridae and Mytilidae. This microbial activity produces calcium carbonate (CaCO3), which is deposited on the seafloor and forms a layer of rock. During a
They are derived from the chemical and mechanical weathering of rocks. Biogenous sediments are composed primarily of the protective outter covering of small marine animals and plants. If these remains comprise at least thirty percent of the sediment it is called an "ooze". "Oozes" were named for the types of organisms that formed them. Hydrogenous sediments form as a result of the chemical reactions that occur in the
Examples of regional metamorphic rocks include schist and gneiss. Thermal metamorphic rocks, also known as contact metamorphic rocks, are formed by extreme heat along with quite a bit of pressure. The pressure pushes the molten rock against the Earth's surface, causing it to recrystallize. Examples of thermal metamorphic rocks are marble and sandstone
The actual speed of P and S seismic waves depends on the density and elastic properties of the rocks and soil through which they pass. In most earthquakes, the P waves are felt first. The effect is similar to a sonic boom that bumps and rattles windows. Some seconds later, the S waves arrive with their up-and-down and side-to-side motion, shaking the ground surface vertically and horizontally. This is the wave motion that is so damaging to structures.
Along the coast of south America, the Nazca plate is moving towards the south American plate. The Nazca plate is oceanic, hence denser; therefore it is subducted underneath the continental crust into the mantle. As the Nazca plate bends down into the mantle it forms a deep oceanic trench. This is made up of long, deep gorges in the sea bed that occur around the edges of some oceans including the Pacific Ocean. The force of one plate being dragged under another causes intense friction and the pressure increases.
An environment in which Stromatolites would live and grow include: anaerobic, marine (lakes, bays, oceans), high salinity, low tide, warm temperature, poor water circulation or shallow water. Recently, Stromatolites have been found in Pre-Cambrian rocks at Shark Bay in Western Australia (where they were first found),
Where do these rocks come from? Sedimentary rocks come from the very thing they are named after; sediment. These rocks originate from weatherization and a few other processes over a long period of time. For example, if a mineral is stripped from some rocks during weatherization and are carried to a body of water, the minerals will eventually settle at the bottom of the lake and through some other processes settle down and form rocks (Murck, Skinner, & Mackenzie, 2008). Dead plants and animals, along with minerals already at the locations help to create the sedimentary rocks and their unique characteristics.
Another source is the release of salts as rocks weather. Another possible cause could be ancient drainage basins or inland seas that evaporated during dry periods, leaving behind salt deposits that still remain today making that land infertile and useless for any agricultural purpose. However, rising groundwater levels are bringing previously stored undisturbed salt to the surface where it affects soils, streams, vegetation and farming. Rising groundwater levels can be caused in two different ways. The first is the naturally changing Australian landscape.
J. Subbiondo © 2004The CrustThe outer layer of the Earth is called the crust. It is made up of rock that floated to the surface when the Earth was formed. It is not a continuous layer, but is made up of large masses called tectonic plates.These plates drift slowly across the Earth's surface (tectonic means moving).The movement of these plates creates mountains and valleys.At weak points in the crust, it causes volcanic eruptions. And when plates bump into each other, earthquakes occur -- emitting shock waves or vibrations called seismic waves. The crust is the Earth's coldest layer.