chapter 2 Flashcards
what is the PETM and how did it happen?
Paleocene- Eocene Thermal Maximum
56 million year ago global temperatures were much higher by about 6 degrees. it is thought that volcanism in Greenland and northern Canada may have contributed to the release of large amounts of methane- a greenhouse gas that results in global warming
approx 4 billion years ago there was a cataclysm, perhaps the most important we know of. what was it and why is it so important?
the early Earth collided with a large object (about the size of Mars) called Thea. during the collusion Thea disintegrated. Earth was damaged but remained more or less whole.some of the Thea’s mass was absorbed by Earth to give it a bigger core. This may have given Earth its stronger magnetic field and more solar protection
the idea that climate has a significant impact in the volcano activity is based on 3 factors. explain
climate affects volcanic activity because of the transferred mass in particular water. water and therefore mass, is transferred by:
- Precipitation
- Formation or melting of glaciers
- Changes in sea level; related to air pressure and wind
there is little doubt that volcanic eruptions have had a significant impact on the Earth’s climate. what are the 3 things from a volcanic eruption that have the greatest impact on climate. explain each
volcanic eruptions release an abundant gas that can cause climate change:
- SULPHUR DIOXIDE. in the the atmosphere it reacts with water to produce sulphuric acid. this absorbs and blocks solar radiation causing the Earth to cool
- CARBIN DIOXIDE. this gas traps solar radiation which warms the Earth
- CHLORINE. and such gases that deplete the ozone layer
what os the asthenosphere, how does it form and why is it important?
the lower crust and upper mantle (100 to 250 km deep) that is partially melted. only about 10% has melted. more of it is close to melting. the asthenosphere is the primary source of magma for volcanoes to erupt.
what is Paul’s Volcano and why is it significant?
an active stratovolcano (explosive) in Alaska near the Pacific. its important because it tends to erupt only during certain times of the year - in the winter.
this regular eruption pattern of the volcano is thought to be caused by higher, sustained sea levels, and therefore more weight at the coast, cause by winder winds blowing from the pacific ocean to the coast. this additional weight changes the crust in and around the volcanos causing it (the crust) to bend differently. this changes the volcano in a way that magma reaches the surface more easily
what os the ‘Volcano Season’ and how does it happen?
a regular pattern of eruption related to weather and climate. the underlying cause is changes in the distribution of weight in the form of water, as part of the water cycle.
this includes:
-changes in sea level
-changes in precipitation ( rain &snow)
-changes in glacial ice
what was the ‘Great Oxidation Event’ and was it so important?
was the appearance of significant amounts of oxygen in the Earth’s atmosphere. the oxygen accumulates in the atmosphere, new opportunities for life to evolve. however, the more primative life forms that already exist are now restricted as to where they can live. oxygen is poisonous to them. also the chemistry of the atmosphere changes with the presence of oxygen and its ability to form other molecules such as CO2
what was the “Great Dying’ and why did it happen?
was the largest known extinction about 250 million years ago @ the end of the Permian Period. this thought to have been the result of large, sustained volcanic eruptions in what is now Siberia in Russia. Effusive eruptions (like Hawaii) released large concentrations of CO2. this then changes the nature of the atmosphere and oceans.
what is the Pleistocene Ice Age and how was it started?
started about 2.6 million years ago. its the most recent ice age. The onset of an ice age is related to the Milankovitch cycles - where regular changes in the Earth’s tilt and orbit combine to affect which areas on Earth get more or less solar radiation. When all these factors align so the northern hemisphere gets less solar radiation in summer, an ice age can be started.
what is the Eemian Interglacial?
was the interglacial period which began about 130,000 years ago at the end of the Penultimate Glacial Period and ended about 115,000 years ago at the beginning of the Last Glacial Period.
What is the Younger Dryas and how did it happen?
This near-glacial period is called the Younger Dryas, named after a flower (Dryas octopetala) that grows in cold conditions and that became common in Europe during this time. … About 14,500 years ago, Earth’s climate began to shift from a cold glacial world to a warmer interglacial state.
the 4 events listed in q #1-4 describe the Earth’s climate at various stages in the past.what do these events say about our climate and why is this so important?
Earth’s climate is constantly changing. it goes through ice ages that get followed up by warmer temperatures.
