Geology Final Exam Study Guide

hFeel free to add and edit as you please. It will be really awesome if we can type out a short answer to 8 each of the bulleted questions! - J.W. Turner

Questions about the material that classmates may be able to answer:

1. Are you sure it’s supposed to say “New Zealand,” not “Hawaii?” (below) ← Yeah, it’s supposed to be hawaii ← No, it’s supposed to be new zealand. I double checked. ← Can you tell us which slide you found this info on No its hawaii from ancient bump notes
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3.Could someone define a forcing?
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PLEASE be sure to bold/color your answer so it is easier to read...

Studying Suggestions (same tips as in the previous study guide):
• Focus on the notes – and in particular those that are in bold, large font, or in the ‘summary’, ‘bottom line’, ‘societal relevance’ sections. Use the book to supplement the lectures in areas you feel you need more information.

• Many of the climate events we have discussed require an understanding of ocean and atmospheric circulation, the notion of feedbacks, forcings (the difference in how much energy is absorbed and how much is released), thresholds, and oceanic and longer-term carbon cycling processes (1000 years to overturn). If these terms make you nervous then you want to look back over the relevant set of note.

• Don’t get bogged down in the details of the notes. If you can write one or two summary sentences for each ‘section’ of the notes then you probably have a good sense of what is important to remember. Try to recall what I repeatedly said in class was the ‘primary point to get out of any given past climate example (e.g., the decade- to century-long megadroughts of the Medieval Warm Period).

• Same advice holds for the various ‘time-periods’ – IF you can write 2 or 3 sentences that summarize the main point(s) made by the material presented for each ‘case study of past climates’ made in class then you probably know enough. You do not need to memorize the names of different time periods we discussed and that are covered in the notes. Solely be able to recognize a couple of key words (e.g., Snowball Earth, PETM (Paleocene Eocene thermal maximum)(this was rapid warming)) and/or the general time period (e.g., Mesozoic Era) so that you can recognize and pick the correct one out of ‘a line-up of possible answers’. These time periods were used to illustrate concepts we discussed earlier in the quarter (e.g., the utility of the silicate weathering-carbonate formation process and organic carbon burial in sequestering CO2, analogues for the future changing climate, ice stability thresholds, role of ocean circulation in climate change) – so think about what the concept(s) was for each time period & about the societal relevance (i.e., lessons learned) of these past climate change events.

Concepts & Keywords (bolded) to be familiar with:
Carbon Capture
Sequestration
Paleocene-Eocene Thermal Maximum (PETM)

• What is meant by the climate-atmospheric CO2 link? – & has it been generally robust (strong) through the past? That is, consider whether past warmings in Earth history have repeatedly involved increases in greenhouse gas levels in our atmosphere.

Interesting correlation since global warming has been proven. And correlations between temperature and CO2 have always been interesting, the sense that temperature rise before the CO2 levels.

· The geologic record of the past 4.6 billion years reveals alternating periods of global warming and ice-free conditions (referred to as ‘greenhouse times’) with cold periods with ice at the poles (referred to as ‘igloo times’)
· Rapid (on the scale of decades to several centuries) & large climate changes were the norm during these major climate transitions from icehouse to greenhouse and vice-versa
· Atmospheric CO2, climate conditions & the amount of continental ice we have on Earth are linked – when CO2 goes up, so do surface temperatures and ice sheets began to melt & vice-versa when CO2 goes down.

• What is carbon capture and sequestration? And how is it based on the natural rock cycle? What is its relevance to our future?

Carbon capture is the process of capturing waste carbon dioxide (CO2) from large point sources, such as fossil fuel power plants, transporting it to a storage site, and depositing it where it will not enter the atmosphere, normally an underground geological formation. The aim is to prevent the release of large quantities of CO2 into the atmosphere (from fossil fuel use in power generation and other industries). It is a potential means of mitigating the contribution of fossil fuel emissions to global warming and ocean acidification.

Carbon sequestration is the process of capture and long-term storage of atmospheric carbon dioxide (CO2) and may refer specifically to:
The process of removing carbon from the atmosphere and depositing it in a reservoir.
The process of carbon capture and storage, where carbon dioxide is removed from fuel gases, such as on power stations, before being stored in underground reservoirs.
Natural biogeochemical cycling of carbon between the atmosphere and reservoirs, such as by chemical weathering of rocks.

Liquefy CO2 underground. Coccolith and ocean seeding. Plant more trees. Man-made carbon sequestration via chemical processes

• What role did silicate weathering-carbonate formation play in the Snowball freeze-dry events?

At a huge time-scale, (100,000s to 10s of millions of years) silicate weathering and burial or oxidation weathering of organic carbon controls atmospheric CO2 levels. Silicate weathering is a negative feedback loop linked to climate change. There’s an initial change (global warming), which results in a warmer climate, which results in increased temperatures, rain, and vegetation, which results in increased chemical weathering, which finally results in increased removal by silicate weathering and results in the reduction of the initial warming.

Silicate weathering carbonate formation decreases CO2 which cools more. Weathering then capture more CO2 which results in a feedback.

CO2 levels varied between present day levels and very high highs. These oddball glaciations are the classic example of the long-term carbonate-silicate cycle. With such reduced levels in CO2 caused by silicate weathering on land and carbonate formation in the oceans, the reduced CO2 levels led to a complete freezing over of the Earth.

• How did climate trigger the onset of multicellular animal life?

Last glaciation may have been the trigger for multi-cellular life. The organisms that survived through these freezes had to endure a subsequent brutal greenhouse - geologic history tells us that is one way to trigger evolution. Evolutionary rates at this time were 20 times faster than normal. Multicellular animal life (virtually all animal phyla living today) on earth first appeared soon after the last snowball event.

• How were latitudinal temperature gradients different than today during past CO2-forced greenhouse times? How do atmospheric processes such as cloud types and hurricanes factor into this?
Latitudinal temperature gradient is lower. Increased hurricane activity changes the location of deep-water formation in the ocean --> increasing heat transport by the atmosphere and ocean. Cloud types can change albedo effect. More aerosols --> more cloud droplets. Periods of increased volcanic explosions lead to higher cloud condensation nuclei, more of denser reflective clouds and increased albedo-ultimately global cooling. Typhoons are more intense since they require warmer ocean temps. Cloud types can trap or reflect heat/sunlight. Also in previous greenhouse times there was a lower “tropic-to-poles” temperature gradient.

• What role did superplumes play in past warm periods? Do we have active mantle plumes today (where)?

Yes, they are still superplumes in Hawaii. Superplumes were how we got out of ice age periods. There was no CO2 on land or in the air but when superplume events occurred they were able to add little by little CO2 via the ocean magma plumes which would slowly warm the earth out of an ice age event.

· The high concentration of sulfate aerosols above the oceans leads to lots of dense low-lying clouds over the oceans
· They increase Earth’s albedo & cool the Earth’s surface
- increased aerosols are short lived (1-2 yrs); cooling is short term

New Zealand and/or Hawaii today

• What forcings led to the cooling of the past 40 million years & how (e.g., role of the Himalayas and Tibetan Plateau in controlling atmospheric CO2 levels and climate)?

A forcing is the difference in sun absorbed vs. sun reflected by the earth.

Himalayan plateau made lots of silicate weathering which cooled the atmosphere via reduced CO2 also changed atmospheric circulation since they were so high.

• What is an oceanic gateway and what role do they play in controlling climate (glaciation at the poles, heat transport)

Gateways are narrow passages linking the major ocean basins. Changes in their configuration alter the amount of sea water exchanged between oceans as well as heat, and salt carried by sea water

cool moist air to continents.
Bring moisture to high latitude to make ice sheets

Adding greenhouse gases to the atmosphere such as CO2, increased ocean heat transport to the polar regions, decreased albedo. Ocean transported twice as much heat from the equator to the poles. Phtyoplankton such as coccoliths emit a chemical called dimethyl-sulfide, which create more clouds

• What are marine methane-gas hydrates (i.e., methane ice) and what role did they play in past global warming? Could they play a role in our future climate? And how?

Marine methane-gas hydrates are ice crystals with CH4 trapped inside at the bottom of the ocean. They can melt due to to increased ocean warming and since CH4 is a greenhouse gas they help create a period of warming.
They could be a source of fuel, but also could melt and release making a warmer earth (positive feedback).

• Why is Paleocene-Eocene Thermal Maximum (PETM) our best analog for understanding the current fossil-fuel-burning-driven global warming? And why? And what have we learned from this analog?

That warming can lead to extinction, warmer/more acidic oceans and changes in the carbon cycle. So apply that current warming?
Fastest release of natural carbon gases ; same amount=analog

PETM released massive amounts of CO2 in atmosphere (5000 GTons over 3000 year period) Even though the rate of release and the amount (magnitude) of release was very large during the PETM, it was still less than what we are experiencing now. So changes in climate and life that occurred then are probably minimally what we might expect in our future.

Rise of humans, too hot for large mammals.

Higher sea levels and ocean anoxia(no oxygen) toxic for life

• Why did the oceans go anoxic during the super greenhouse times of the Mesozoic (ie warm period due to PETM)? And what relevance does this have to future global warming? Recall the irony of these ‘oceanic anoxic event’ – i.e., they involved burial of huge amounts of marine microplants (coccoliths and such) on the seafloor and in rocks, these turned to oil – the very petroleum we pump out now that leads to global warming.

This means that ocean does not decompose things so they accumulate on the bottom. LEads to oil
Amount of oxygen in water is little. Its relevance is that we have so much CO2, our coast lines are going to experience this and plants will grow rapidly. Not enough CO2 and plants will die.

• What role did climate play in the evolution of primates?

During colder periods, gigantism occurred. As a global warming happened gigantism slowly ended and this along with warming increased the survivability of smaller mammals.

• What is the role of dimethyl-sulfide (DMS) produced by coccoliths in cloud formation and global warming or cooling? And how this natural process has been proposed to be used to combat global warming.

Coccoliths make DMS which aerosols, makes sulfuric acid and leads to nucleation for clouds. Make more clouds leads to more cooling.

Process can be to release sulfur into the air and do the same thing, thus clouds and combating global warming.

But we could end up with acid rains

• In what type of ‘glacial condition’ do we currently live? Are these ‘typical’ climates throughout Earth history?
Currently in an “interglacial period” with wetter conditions and an elevated atmosphere
We are currently in the middle--or at least suppose to be--and these are rare climates

• What is an ‘ice core barometer’? – and what does it tell us about atmospheric CO2 during glacial and interglacial times.

Drill a hole. Take a look what’s goin on for the past thousands years by looking at the content of the air bubbles

• Has climate change in the past been gradual (linear) or does it occur abruptly? And how climate thresholds play into that answer.

When it comes to restoration, it is a gradual process that takes a long time. Abrupt changes also occur with an overall 2 degree temperature change.
Once it reaches a climate threshold or tipping point, the change occurs abruptly (over the course of decades or centuries).

• What is meant by a ‘climate threshold & tipping point’?

Point at which the climate reaches a point where it cannot recover. Changes will continue even if the original source is removed.

• How the Pleistocene ice ages of the past 2 million years illustrate that climate change can be amplified by positive feedback processes in the Earth system?

The Earth heated before atmospheric greenhouse gasses were released, which shows that global warming can release greenhouse gasses and create more warming. (positive feedback)

With the change of the amount of ice at the poles,

• What are the 3 main Milankovitch orbital parameters? In general (NO DETAILS) & how do they influence climate on Earth (i.e., seasonal insolation)? In general, on what time-scales to they operate? How do they effect seasonal changes in climate today? How can we expect our climate in the Northern Hemisphere to change in the next 13,000 years?

3 parameters are
Obliquity (tilt of earth's axis) time scale: 41,000 yrs
The greater the tilt, the more extreme the season, especially at high latitudes
Eccentricity (orbiting in a circle or an ellipse)
Full cycle: 100,000 & 400,000 yrs
@ elliptical, the earth is closer to the sun in one season than the other perihelion: closer to sun=more sunlight hitting earth aphelion: away from sun=less sunlight hitting earth procession of the equinox (where the axis wobbles back and forth) time: 26,000 yr
N.Hemisphere has low seasonal temp. = mild summer / winter
S.Hemisphere has high season temp. = harsher summer / winter
In 13,000 yrs the N.Hemisphere summer will fall @ perihelion = larger seasonal temp. contrasts

• What role did Milankovitch orbital parameters play in the climate fluctuations of the glacial-interglacial cycles of the past 2 million years (Pleistocene)?

Changes the amount of sun that hits the earth. Can lead to climate shifts
Orbital parameters change climatic conditions by changing the intensity of the Sun’s radiation to Earth, thus the intensity of the Earth’s seasons & not by creating an overall warming or cooling.

• Glacial-interglacial cycles of the past 2 million years - how (generally) did CO2 and temperature change with each cycle? Where the changes coincident? If not, why not. How does the CO2 level of the atmosphere today compare to that of the interglacials of the past 2 million years?

Basically up and down in a wave pattern. Hot period, cold period, hot period etc... Lately it has held pretty constant but it is slowly warming.

• What are the main positive feedbacks that amplify the climate changes created by Milankovitch orbital parameters & that can be triggered with continued global warming

(e.g., reef formation, changing ice albedo, changes in ocean circulation, changes in the amount of biological pumping, changes in the amount of Fe-fertilization of photosynthesizers in the ocean due to changing wind strengths).

• what are the best paleoclimate tools for reconstructing ocean temperatures, changes in ice sheet extent (volume) and atmospheric greenhouse gases during these ice ages?

Shells!
Oxygen isotopes (shells)--an isotopic thermometer of Earth’s surface temperature, track of the volume of continental ice sheets forming through time.

• What is meant by the concept ‘we may have missed our next ice age” – and why?

If you follow the current trends looking back in time we should have had an ice age event already but instead we have had increased warming

• How did the recent ice age influence human migration “out of Africa’ and Asia?

Sea levels fell and new land is exposed that can be walked on.

• Why did mammals grow to be giants (e.g., Mammoths) during the Pleistocene ice ages? And why did they go extinct (over hunting or climate change)?

Larger animals have an advantage during cold periods because of surface area/volume ratio. These include giraffes, giant crocodiles, and blue whales.

Among the main causes hypothesized by paleontologists are natural climate change and overkill by humans, who appeared during the Middle Pleistocene and migrated to many regions of the world during the Late Pleistocene and Holocene. A variant of the latter possibility is the second-order predation hypothesis, which focuses more on the indirect damage caused by overcompetition with nonhuman predators. The spread of disease is also discussed as a possible reason. Also it got hella hot.

• Why did the slow down in sea-level rise ~ 6,000 years ago - during the last deglaciation – lead to the emergence of permanent settlements and city-states?

It allowed settlers to live in river valleys that no longer flooded or rose in water level. Provided good land for a stable society.

• What is the concept of ice hysteresis & what relevance does it have to the future stability of our continental ice sheets?

Hysteresis--the ‘inertia’ of ice sheets. Keeps our present ice sheets from melting under atmospheric CO2 levels.

• What are the glacial floods and scablands in the Pacific Northwest? What relevance do they have to the historical and biblical floods?

Erosional features developed throughout the Pacific NW after ice dams collapsed & carried immense floods

• The Younger Dryas event – what was it, why did it happen, how it is an analog for our future as Arctic sea ice & Greenland ice sheets melt? How quickly did climate change? What caused this climate change? Could this happen again with continued global warming?

Period of intense dry weather. Younger Dryas- a very cold period. Global warming lead to accelerated rate of melting in the N.Hemisphere (Greenland & Arctic Sea ice) ice freshening of seawater, ultimately leading to lower rates of deep water formation in N.Atlantic.
· Why: changes in flowpath of meltwater from N. American ice sheet as it melted. Lead to fresh water cap in N. America which slowed the conveyer belt and resulted in less heat

• How did climate change promote the development of agriculture and animal husbandry.

In order to have a constant supply of food and other resources also allowed colonization of river valleys once the climate stabilized.

• Why are periods of transitional climates (such as the last deglaciation or global warming periods) particularly very susceptible to abrupt climate change?

These transitions are most sensitive to climate change because small “climate forcings” can be amplified into abrupt climate change

• How did the Medieval warming impact the northern Europeans?

Warming led to less ice and let the vikings expand over northern nations. Opened up some oceans channels for trade and commerce for Northern european coastal cities.

Wait, it’s this the “Little Ice Age” because if it is that means it got colder in Europe and thus the vikings couldn’t travel as far and all of Europe had a hard time harvesting

• How did the Medieval warming impact native Americans (e.g., the Anasazi, the Mayans)?

Led to droughts that led to deaths and societal collapse.

• What are megadroughts and how do they relate to climate change? Overall, what role did they have in the rise and fall of different civilizations/societies such as the Akkadians and the Anasazi?
Mega drought were years long extreme droughts that occurred in a few decades. Since many of these societies were in the dryish but had a sustainable water supply from the rain and underground water supplies but with a long drought, people migrate or die.

• What is the evidence for megadroughts throughout the Sierra Nevada region of California during the Medieval Climatic Optimum? What are the projections for rainfall and snowfall in California with continued warming?

Evidence in the Sierras is that there are dead trees at the bottom of lakes which suggests that there was little water back then. This allowed for trees to grow in river valleys that later became lakes.

• What are sunspots? What do Sunspot cycles have to do with climate change? Can changes in sunspots explain the warming of the past few decades? Why or why not?

Sun spot is a spot on the sun that is really cold, but is surrounded by VERY hot areas. These areas give off more radiation

sunspots can explain it since they were directly correlated with warming and cooling trends, but lately sunspots have decreased and warming is still increasing.

• What is the current level of CO2 (ppmv) in the atmosphere? (yup, it IS important to know)

400 PPM as of this year!

• How much of the US total energy comes from fossil fuels? 85%How does this compare to other countries? we consume 25%, when we only have 5% of the worlds population. What is the dominant electricity source for the US?Coal & natural gas Which fossil fuel type puts out the most carbon dioxide per unit of energy?Coal What is the consumption gap? The difference between the rate at which we consume and produce How much faster are we putting fossil fuel sourced CO2 into the atmosphere vs. the time it took to make the fossil fuels (order of magnitude) & what are the implications of this? 100,000 times faster
The consumption gap is the growing difference between the amount of oil we are pumping out of the ground (we have few reserves left) and the growing demand for oil as countries with growing economies are demanding more and more of it.
37% Petroleum, 25% natural gas, 21% Coal, 9% Nuclear, 8% Renewables

• What is meant by ‘energy is empowerment’? Direct correlation between gross national product of a country and its per capita CO2 emissions per year What role has the US played in CO2 emissions to the atmosphere over the past several decades? And who is currently the biggest emitter of fossil-fuel based CO2 to the atmosphere. China

Speculation: Having energy or the ability to use it allows a country to develop faster. This is why the US is one of the more modern countries in the world which is apparent by its very large CO2 emissions.

• What is the Kyoto Protocol and how does it relate to California’s ‘Global Climate Solutions Act’?

Kyoto protocol is a dedication by nations to reduce CO2 to 1990 levels (350 ppmv). Big nations like Russia and China and the US have not adopted it. BUT CA and some other states have. In California, we have passed Assembly Bill 32 in 2006 (‘The Global Climate Solutions Act’).

• What are geoengineering ideas for mitigating climate change – both longwave (CO2 sweeping) and short-wave (increasing albedo)
Long-wave schemes that slow CO2 emissions and / or sweep CO2 out of atmosphere:
Artificial ocean fertilization and super photosynthesis
Scrubbing out excess atm CO2
CO2 Capture and sequestration
Alternative Energy Sources:
Hydroelectric power
Geothermal energy
Solar energy (i.e. Thermal electric power generation, solar cell power generation)
Wind power
Sustainable biofuels
Short-wave scheme: approaches that reduce the amount of sun’s energy by ‘shading the earth’:
Sulfur in the stratosphere
Sea mist in troposphere
'Venetian' space blinds

• What is meant by ‘fertilization of the oceans’ & how does it work? Can it reduce atmospheric CO2 levels to the desired levels?
Fertilizing the ocean with Fe2+ to stimulate productivity by all the marine plants (phytoplankton) that photosynthesize & remove COs from the atmosphere. It requires ‘seeding of high latitude oceans 100 times per year by many larger ships to reduce atmospheric CO2 by 1X10^15 tons of C per year (~1/9 of all of the yearly emissions of CO2 to the atmosphere)

• What are the desired CO2 levels in order to assure that global warming does not go beyond 2°C?
1990’s levels of CO2 emissions

To avoid a > 2°C surface temperature increase, many studies indicate that we need to lower the CO2 in the atmosphere to 400 ppmv . . . maybe even 300 ppmv by year 2050.

• What is meant by ‘sulfur seeding the atmosphere’ & how does it work? What are some of the downsides of this approach?

Spray the air with sulfur particle so that water droplets have a cloud condensation nuclei. The increase of clouds will increase the albedo effect and cool the earth. Bad things are that it will POUR DOWN ACID RAIN and change the atmospheric circulation patterns.

• What is a Lackner unit? CO2 capture directly out of the air!! Is it economically feasible and a realistic technique for mitigating high levels of atmospheric CO2?

Large fans with CO2 capturing minerals. CO2 is captured and then trucked away in liquid form.

Not realistic bc for a population of 10 million people we would need ~300,000 of these spread out across the world’s deserts and ice sheets
Cost: about the same as the US economic stimulus package - but every year for a century

• What is carbon capture and sequestration? CO2 captured at industrial site, liquefied under pressure and piped into an underground site from which the coal, oil or gas was originally removed OR pump the liquefied CO2 into the deep ocean. What does it have to do with the natural mineral weathering processes we learned earlier in the quarter? ‘Weathering’ reactions between the CO2 and the rocks allows for CO2 to be mineralized and locked away
Where does the liquefied CO2 go after capture? Store at the depth of the ocean. Is the deep ocean a permanent reservoir for this CO2? no, after ~1000 yrs (overturn of deep ocean) CO2 will come back up

• What are viable alternative energy sources? How do the greenhouse gas emissions of these energy sources compare with fossil-fuel based energy? Which alternative energy sources are underutilized? What is geothermal energy? How does California compete in its development of wind and solar power? Which biomass-based ethanol sources are viable as fuel and which are not? What is the next generation of sustainable biofuels?
-Viable alt. energy sources: hydroelectric, geothermal, solar, wind power, sustainable biofuels
- The GHG emissions of these alt. energy sources are far less compared to natural gas (which is already cleaner than coal/petroleum), let alone oil (petroleum) & coal( dirtiest!).
- Wind turbines currently supply 8% of California’s electricity. But wind could produce up to 20% of US power demands if installed throughout regions with steady winds.
- Geothermal energy: Uses the energy of groundwater heated by magma beneath the surface. It is an economic target for the US- currently only 1% of US energy. And it has much potential given the geothermal heat distribution in the US.
-Cali’s wind and solar power: less than 1%
-The Brazilian use of sugar cane as biomass-based ethanol is viable -- fuel efficient 1:8 ratio. The US use of corn for biomass-based ethanol is NOT viable-- fuel in-efficient 1:1.3 ratio
- Future sustainable biofuels: algae, or cellulosic biomass(wood pulp, grasses like jatropha)

• What is a Flettner ship? And how will they contribute toward mitigating climate change? Is there a big ‘C cost’ to the environment of using these?

Large ship that makes aerosol of sea spray and leads to whiter clouds.

Could lead to less rainfall in the ocean since cloud droplets won't turn into rain, and science is not sure what else.
Cost about $2,000,000 USD each

• What is a Venetian Space Blind? Is this a viable (good) idea for mitigating climate change? Why or why not?
-The Venetian Space Blind is a processes that essentially creates “artificial clouds” in hopes to repel more sunlight. But this plan is really expensive to carry out. It would cost nearly $5 trillion dollars. People are skeptical to this and say that it would be a better idea to just invest that kind of money into renewable resources and greener sources of energy, such as building wind turbines and solar power plants. Also, if the controls of these “artificial clouds” fell into the wrong hands, they could possibly used against us.

A 5 trillion dollar project to take 40 years in which a cloud of small metal (robots? yes, definitely robots) objects would form a cloud in a fixed point in space (Lagrangian) and they could be remotely controlled to adjust the amount of sunlight that passes through it to hit the earth to help stem the global warming occurring.
This is not a good idea because its costly, time consuming, there are other options and if someone else grabbed the remote they could incinerate us

• What does it mean to suggest that ‘we are committed to another 100+ years of global warming (O.1°C/decade) and sea-level rise even if we scale back our emissions of CO2?
The effects of positive feedbacks are taking role. it means that it will take ~100 years for us to recover and stop warming based on current CO2 models.

• And of course . . . . what does a paleoclimate perspective on climate change offer as insight for understanding and dealing with our current climate change situation that is beyond what can be obtained from studying solely the instrumental (historical) record?

What is the purpose of geology?

to learn more about earth in order to both help it and its inhabitants