Open ended Earth Science Final

What are the two hypothesis for the origin of Earth's water?

-comet impact theory. The belief was that earths water came from comets that impacted on the early Earth .-large percentage of water was already in the rocks on Earth when it was created.

How long ago were the dinosaurs wiped out? What was the cause?

66 Million years due to K-T Mass Extinction: a large asteroid impact and a giant volcanic eruption

What might be the cause for late heavy bombardment stage?

A cause is gravitational resonance between Jupiter and Saturn for disturbing orbits within the asteroid and Kuiper belts for such instability

Give 3 differences between Continental Crust and Oceanic Crust

Composition: Continental Crust: Continental crust is primarily composed of granitic rocks, which are rich in silica and aluminum. These rocks are lighter and less dense compared to oceanic crust. Oceanic Crust: Oceanic crust is primarily composed of basaltic rocks, which are rich in iron and magnesium. These rocks are denser and heavier compared to continental crust. Thickness: Continental Crust: Continental crust is generally thicker, ranging from 30 to 70 kilometers in depth. It can reach up to 70 kilometers beneath mountain ranges. Oceanic Crust: Oceanic crust is comparatively thinner, with an average thickness of about 5 to 10 kilometers. Age: Continental Crust: Continental crust is relatively older compared to oceanic crust. Some areas of the continental crust date back billions of years, making them significantly older than the oceanic crust. Oceanic Crust: Oceanic crust is relatively young, with most of it being less than 200 million years old. This is because oceanic crust constantly forms at mid-ocean ridges and is eventually consumed in subduction zones.

Describe briefly all the chemical layers of the Earth with 2-3 of their respective properties.

Crust: -The crust is the outermost layer of the Earth and is composed of a variety of rocks and minerals. -It is relatively thin, ranging from 5 to 70 kilometers in thickness. Mantle: -The mantle lies beneath the crust and is the largest layer of the Earth by volume. -It is predominantly made up of solid rocks and minerals, including silicates. Core: -The inner core is the deepest layer and is primarily composed of solid iron and nickel. -It is under tremendous pressure, causing it to remain solid despite extremely high temperatures.

Describe briefly all the different divergent boundaries with 2-3 of their respective properties.

Divergent boundaries -- where new crust is generated as the plates pull away from each other. Convergent boundaries -- where crust is destroyed as one plate dives under another. Transform boundaries -- where crust is neither produced nor destroyed as the plates slide horizontally past each other.

What is Plate Tectonics Theory? Some evidences to support this theory

Earth's outer shell (lithosphere) is divided into several plates that glide over the Earth's rocky inner layer above the soft core (mantle). Evidence for the theory of plate tectonics is continental drift, appearance of younger crustal layers in the ocean, earthquakes along plate boundaries called fault lines, the presence of similar fossils and rocks on separate continents, and the matching shapes of continents that once fit together as a larger continent.

Why is Earth's Inner Core Solid?

Made up of Solid iron-nickle metal the combination of extremely high pressure and the presence of impurities and defects contribute to the solid-state of the Earth's inner core despite the high temperatures.

Give a brief description of what happened during the Cambrian Explosion i.e. what type of life thrived during this period?

It was when most of the major animal groups started to appear in the fossil record, a time of rapid expansion of different forms of life on Earth. Many kinds of invertebrates and the first vertebrates—fishes—appeared in the fossil record.

Describe briefly all the physical layers of the Earth with 2-3 of their respective properties.

Lithosphere: -The lithosphere is the rigid outer layer of the Earth, encompassing both the crust and a portion of the uppermost mantle. -It is characterized by its solid and brittle nature, making it capable of fracturing and forming tectonic plates. Asthenosphere: -The asthenosphere is a semi-fluid, partially molten layer located beneath the lithosphere in the upper mantle. -It exhibits plastic deformation, which means it can flow and deform over long periods of time under high temperatures and pressures. Mesosphere (Lower Mantle): -The mesosphere is the lower portion of the mantle, extending from the bottom of the asthenosphere to a depth of approximately 2,900 kilometers. -It is characterized by high pressures and temperatures, which increase with depth. Outer Core: -The outer core is a liquid layer located beneath the mesosphere and surrounds the solid inner core. It consists primarily of molten iron and nickel. -The outer core's high temperatures and flow of liquid metal generate the Earth's magnetic field. Inner Core: -The inner core is the innermost layer of the Earth, located at the very center. -It is primarily composed of solid iron and nickel due to the intense pressures exerted by the layers above it.

Describe briefly all the different convergent boundaries with 2-3 of their respective properties.

Oceanic-Continental Convergent Boundary: This boundary forms when oceanic crust collides with continental crust. Properties: -Volcanic Activity -Earthquakes Oceanic-Oceanic Convergent Boundary: This boundary occurs when two oceanic plates collide. Properties: -Island Arc Formation -Trench Formation Continental-Continental Convergent Boundary: This boundary occurs when two continental plates collide. Properties: -Mountain Formation -Seismic Activity

Which eon saw the evolution of multicellular organisms? Explain briefly some characteristics of lifeforms found in this eon.

Proterozoic Appearance of eukaryotes happened around 2.1 to 1.6 billion years ago. Eukaryotic cells are more complex with nuclei and organelles. The nuclear DNA is capable of more complex replication and regulation than that of prokaryotic cells. The organelles include mitochodria for producing energy and chloroplasts for photosynthesis

What are the hypothesis for the origin of life on Earth? Explain briefly

RNA molecules could have spontaneously formed and were capable of catalyzing their own continuing replication

3-4 difference between subduction zone and collision zone.

Subduction occurs when oceanic and continental plates move together. The oceanic plate is forced under the lighter continental plate. Collision occurs when two continental plates collide. Neither plate is forced under the other, and so both are forced up and form fold mountains.

Great Oxygenation Event (GOE) took place in which eon? Describe briefly what happened in this event.

The Great Oxygenation Event occurred during the Paleoproterozoic. The build-up of oxygen in the atmosphere was caused by the presence of cyanobacteria that produced oxygen and allowed for the development of multicellular life.oic.

What is Radioactive Decay? Give 3 differences between each of the different types of Radioactive Decays.

The process of unstable atoms changing into smaller more stable atoms. Gamma -has no mass -lowest ionization capability, -most ability to pass through materials. Alpha -heaviest type of radiation -highest ionization capability -least ability to pass through materials. Beta -Composed of single, high energy electrons. -Have higher penetration ability compared to alpha -lower ionization

How was Earth's crust was formed initially? Explain briefly.

Water trapped inside minerals erupted with lava, a process called "outgassing." As more water was outgassed, the mantle solidified. Materials that stayed in their liquid phase became Earth's crust.

Mid Ocean Ridge and 3-5 characteristics of this zone.

is a continuous range of underwater volcanoes that wraps around the globe like seams on a baseball, stretching nearly 65,000 kilometers (40,390 miles). The majority of the system is underwater, with an average water depth to the top of the ridge of 2,500 meters (8,200 feet).

How is Continental Rift Zone created?

reflected heat back into the mantle develops strong convection currents that push super-heated mantle material up against the overlying plate, softening it. Tensional forces created by this convective upwelling begin to pull the weakened plate apart. As it stretches, it becomes thinner and develops deep cracks or faults. Eventually, plate sections located between large faults drop into deep depressions known as rift valleys.

How is Subduction zone initiated?

subduction zones start as passive margins, where oceanic and continental plates come together, and then gravity initiates subduction and converts the passive margin into an active one.

What is Continental Drift Hypothesis? - Some evidences to support this hypothesis

that the continents could move around on Earth's surface. The evidence for continental drift included the fit of the continents; the distribution of ancient fossils, rocks, and mountain ranges; and the locations of ancient climatic zones

What are the functions of Earth's core?

the functions of the Earth's core include generating the planet's magnetic field, which protects us from harmful solar radiation, and providing heat and energy that drive dynamic geological processes on Earth's surface.

What is Paleomagnetism?

the study of magnetic fields frozen within rocks, basically a fossilized compass. When igneous rocks are in their liquid state as magma or lava, the magnetic poles align with the Earth's magnetic field. When the rock solidifies, it is frozen into place, creating a permanent paleomagnetic record.