GEOL 101 1nd Edition Lecture 25 Outline of Last Lecture I. Alpine GlaciersII. LandformsIII. Continental GlaciersIV. Ice AgesOutline of Current Lecture I. Weather v. ClimateII. Earth as a SystemIII. DataIV. Oxygen IsotopesCurrent LectureWeather v Climate-Weather: Day-to-day state of the atmosphere with respect to temperature, precipitation, wind,cloudiness, pressure, etc.- Variations occur on an annual cycyle (seasons). - Generally controlled by regional changes in atmosphere temperature and moisture conditions- Can locally controlled by geographic features such as mountains, and lakes-Climate: Average prevailing weather conditions of a region throughout the year, averaged over a series of years- Variations occur on much longer cycles (decades to tens of thousands of years)- Controlled by long-term changes in atmosphere, hydrosphere, cryosphere, geosphere, biosphereEarth as a System-The earth functions as a complex, interactive system that transfers energy and matter to the five earth spheres:- Geosphere: all the solid rock material, sediment, and molten rock from the surface downto the core.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Atmosphere: envelope of gases held to Earth by gravity, extending 100s of km upward- Hydrosphere: all liquid water at the surface (rivers, lakes, oceans, etc.) as well as groundwater.- Cryosphere: all solid ice in the form of glaciers, snowcaps, sea ice, permafrost, etc.- Biosphere: all living organism on planet Earth.o Anthroposphere (humans): the parts of the environment that are influenced or modified by human activity- What happens in one sphere, will eventually, inevitably affect aspects of the other spheres-How do we know that the Earth’s climate has varied throughout history?- The oldest direct temperature record dates back to 1659 England, and the 1850s semi-globally.-The geologic record gives us gives us proxy (indirect) data about global climate has changed throughout time - Widespread glacial deposits tell us about ice ages- Coal beds tell us about warm, tropical areas- Limestones formed by coral reef environments tell us about warm, shallow seas- Evaporites tells us about arid conditions- Type is fossils (plant and animals) in the rock record give us insight into climate conditions-By studying and understanding the characteristics and interactions between the earth spheres today, we can make inferences and reconstruct how the environment has changed through geologic time- Sea floor Sediments– contain fossils- Oxygen Isotopes – 18O versus 16O isotope ratios in marine fossils- Corals– exhibit growth rings similar to trees, contain oxygen isotopes- Ice Core Records – air bubbles, pollen, dust, volcanic ash, in addition to snowfall amounts- Pollen– show vegetation changes in an area- Historical Documents– written records of events-Sea Floor Sediments- When marine organisms die, their shells and skeletons sink to the bottom and become incorporated into the sediment- The types of fossils give us indication of warm vs. cold water conditionso Formainefera-very sensitive to changing temperatureso There are thousands of species of forams  different species like different water temperature - Many marine organisms build their shells from Ca+CO3from ocean water  Oxygen isotope analysisOxygen Isotopes- Oxygen-16: 8 protons and 8 neutrons (most common)- Oxygen-18: 8 protons and 10 neuronso “Heavy Oxygen”- Both will form in H2O moleculeso The lighter 16O will evaporate more readily then 18O and become incorporated into atmospheric moistureo Precipitation will be more concentrated in 16Oo Oceans will be more concentrated in 18O- Both will form in CaCO3 shells and skeletons of marine organisms -During the ice ages, 16O in the atmosphere precipitates as snow and ice accumulates in glaciers- The glacial ice will be enriched in 16O- The oceans will be depleted in 16O and enriched in 18O- Organisms that make their shells and skeletons out of CaCO3 will have a higher 18O to 16O ratio- During warmer periods, 16O in the atmosphere precipitates as rain and makes its way back into oceans- There will be more 16O in the oceans during warm periods versus during an ice age- Organisms that make their shells and skeletons out of CaCO3 will have a lower 18O to 16O ratio*****Bottom Line: High 18O=Cold Low 18O=Hot*****-Corals- Coral reefs grow in warm, shallow waters- They build their skeletons out of CaCO3 from sea watero This allows us to compare 18O and 16O ratios from them- They exhibit growth rings much like trees doo Their growth rates differ in the winter and the summero Studying modern corals and their growth rings, and comparing them to corals from fossil records gives us good estimate of water temperature -Ice Core Records- Greenland and Antarctic ice sheets record over 400,000 years of earth history in the iceo Snowfall amountso Air bubbles trap paleo-atmosphere CO2 methane, and other gas levels give us information about the composition of the paleo-atmosphere Oxygen isotopes tells us about air temperature- Wind-blown loess, ash, and pollen are deposited on the ice- Dust from meteorite impacts- Photosynthetic ice algae: cryophiles- There is a direct correlation between amount of CO2 in the atmosphere and air temperature. -Pollen- Plant species are sensitive to climate conditionso Dependent on temperature and moisture o Also dependent on altitude and latitude - Pollen gets incorporated into sediment or ice by wind or water.- Paleobotanists can then determine which species of plants were present.- The fossil record also gives us a good indication of the types of plants that were present across the globe and through time-Historical Data- The Year Without a Summer – 1816o Mt. Tambora, Indonesia erupted in 1815-one of the largest eruptions in recordedhistoryo The eruption itself was witnessed and documented by many indigenous people as well as travelers to the regiono Ash and dust blocked out solar rays, to the point that it caused short term global cooling Documented crop failure and food shortages in much of Europe and North America Unseasonably cool temperatures persisted for nearly a decade in some regions, but were most prominent in 1816.- Other forms of historical data include records like:o 1st frost of the