à Name four scientific disciplines, which are part of (marine) geology in a broad sense.
· Sedimentology
à Study of modern sediments such as sand, silt, clay and the processes which lead to their formation (erosion, weathering), transport, deposition and diagenesis. Interpretation of geological history through observations of sedimentary rocks and sedimentary structures
· Tectonics
à Process that controls the structure and properties of the Earth’s crust and its evolution through time. In particular, it describes the processes of mountain building, growth and behavior of strong, old cores of continents known as cratons, and the ways in which the relatively rigid plates that constitute the Earth’s outer shell interact with each other. Plate tectonics describes the large-scale features on Earth’s surface.
· Volcanology
à Study of volcanoes, lava, magma, and related geological, geophysical and geochemical phenomena
· Micro-Paleontology
à Paleontology = study of life that existed prior to, and sometimes including, the start of the Holocene (11,700 BP). It includes the study of fossils to determine organisms’ evolution and interactions with each other and their environments (their paleoecology). Fossils are used to age date sediment layers -> stratigraphy
· Bio-Geochemistry
à Geochemistry uses the tools and principles of chemistry to explain the mechanisms behind major geological systems such as the Earth’s crust and its oceans. In marine biogeochemistry processes and rates of material turnover in the upper sediment column causing changes to the sediment are studied
· Seismology
à Study of earthquakes and the propagation of elastic waves through Earth or planet-like bodies. Also includes earthquake effects such as tsunamis as well as seismic sources like volcanic, tectonic, artificial processes. Seismic mapping uses artificial pressure waves to visualize the sub-surface structures on land and in the ocean bottom
bowens reaction series
à Map à Which Ocean? Where? In which direction are the plates moving?
à What does d18O mean?
to correlate and date marine deposits
Is a measure of the ratio of stable isotopes -> used as a measure of the temperature of precipitation and groundwater interaction
o Measured though differences of 18O and 16O
o Shows temp properties from waters (glaciers/interglacials/no ice cap)
o Harald C. Urey: δ18O ratio dependant from:
o -Variations of the global ice volume
o -Temperature of the ocean
o -Salinity of ocean water
à Which type of rock is associated with the different layers of oceanic crust. Explain the significant differences of the main chemical composition between layer 2A/B, 2C and 3A/B
· 1: Deep-Sea Sediment
· 2A/B: Basaltic Pillow lavas
· 2C: sheeted dike complex
· 3A: Gabbro
· 3B: Layered Gabbro
· 4: Layered and unlayered peridotite
à There is no CHEMICAL difference between Basalt and Gabbro. It is only the lattice structure, that is differing. This is dependent on how much time they had to form.
Igneous Rock intrusive and extrusive
à How can you convert methane into a rock? (Questions regarding reaction in general)
- the bicarbonate or carbonate concentration increases through
1. anaerobic oxidation of methane (AOM)
2. dissociation of organic matter
- Composed of calcite, low‐Mg calcite, aragonite and even dolomite, MDACform a variety of rocks ranging from pure aragonite, to breccias of clasts of mg‐calcite cemented sediment, micritic cemented slabs or roundish concretions, to dolomitic rocks. Typical are very low 13C isotopic values
- that result from the oxidation of methane as the carbon source.
à What are proper features that make stones (crust) melt? Definitely in exam!
1. Add water -> reducing solid curve
2. Increase temperature
3. Reduce pressure
à Name 5 of the most important cations and anions in the water and their concentration.
· Chlorine 55%
· Na 30.6 %
· Sulfate 7.7 %
· Mg 3.7%
· Ca, K, Sr, Br, HCO3
à Explain the Rock Cycle. (Be able to explain different possibilities to get from one point to another).
· Magma à intrusive rock formed and stuck in the earth à uplifted into the atmosphere à creates an outcrop à weathering à grinds down outcrop à forms a sediment, loose mixture of ground down rock à transportation into rivers/streams and beaches à forms compacted sediment à cemented sediment à sedimentary rock is formed (e.g.: sandstone) à buried in earth again à heat and pressure recrystalizes à formation of metamorphic rock à can form new magma àà constantly happening
à Name 4 of the most common elements on earth.
à What is the distance of a Nautical Mile?
· 1852 m (1 Knot = 1 Nautical Mile/hour)
à Given 3D seismic cube of seafloor and fold à What’s the water depth? What’s the depth below seafloor and megaspline? (2-way travel time)
- D = ct/2
- T = time
- C (or v) = velocity
- C = f x lamda
- F= frequenzy (herz)
- lamda = wavelength
à How can I get the age from rocks and sediments? (See L05?)
Radiometric dating methods
à What ist the BSR: bottom simulating reflector?
· The lower boundary of gas hydrate containing sediment layer is the BSR (Bottom Simulating Reflector). It is a horizon of strong reflection in seismic profiles due to distinct change density. Clatherates/gas-hydrates are low in density
à What causes the mantle to melt?
Genaue Punkte !
· Heating:
à Intrusion of hot melt, frictional heating
à Just increased temperatures, does not happen a lot
· Decompression (isothermal):
à Convective upwelling
à Bring up material, one of the most effective ways!
· Hydration:
à Addition of volatiles reduces the solidus
à Where in ocean do sediments have high organic content?
· In coastal margins
· continental margins
à Where was the sediment core taken (in profiles which are provided)
· Need to look at where high organic matter is happening, and OCD is important
· !! when pp is high, organic matter is high and not high oxygen penetration depth
· High organic content not in open ocean
à Where is the carbonate compensation depth (CCD) in the Pacific and in the Atlantic?
- Deeper in atlantic
à Name 2-3 mechanisms that cause advection of pore water.
· When sediments depositing: compact sediment and reduce pore space and squeeze out water (Short: sediment layers-> compaction)
· Tectonic lateral stress
· Mineral conversion (smectite->illite) (silicate tetraeders)
à Name two reactions/processes that release water in marine sediments.
· Respiration of organic matter (e.g..: AOM anaerobic oxidation of methane) = decomposition of OM
· smectite illte conversion -> illite creates when smectite pore water gets out and in deeper depths other material gets in
- oxygen isotope stratigraphy -> purpose
Planktonic forsminifera: to get to know the past sea surface temperature
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