Homework3_S24

GEOS212: INTRO TO OCEANOGRAPHY (Spring 2024) Homework #3 Due 2/9/24 at 12noon NAME____________________________ Rivers, Mountains, Sediment Cycle and Seawater Chemistry This homework should be uploaded (including both your written answers and your drawn-on map) to the Homework #3 folder in the Dropbox on D2L. You can either annotate the Word or PDF version, or you can print the homework out, do it by hand, and then upload a ONE FILE with a picture of each page ( pdf or docx only ). This assignment is due on 2/9 by 12 noon – NO LATE ASSIGNEMNTS ARE ACCEPTED Please make sure you do your own work on this exercise. It is fine to work with others, but the information you write down must be in your own words and in your own format. Identical papers (content & format) will receive zero credit the first time, and will be referred to the Dean of Students for a second offense . This exercise requires your large (30”x45”) National Geographic World Map, the included map of sediment thicknesses, and the included periodic tables. Recall that we have discussed five different mountain building processes : continents pulling apart, subduction zone volcanoes, continents colliding, transform faults, and hot spots. 1. (3 points total) a). South America – Andes Mountains:  There is a very long river shown on your World Map that carries sediment from the central Andes Mountains all the way to the Atlantic Ocean. What is the name of this river? _________________  What is the average thickness of sediment along South America’s east coast (Atlantic)? _____________ km  What is the average thickness of sediment along South America’s west coast (Pacific)? _____________ km  Please give a reason why sediment thickness is so different (east vs west)? _____________________ __________________________________________________________________________  What mountain building process formed the Andes Mountains? ____________________________________  What type of rock would you expect to find in the Andes Mountains? _____________________ b). India: Himalaya Mountains  What mountain building process formed the Himalaya Mountains? __________________________________  What is the name of the river on your World Map that empties into the Bay of Bengal? __________________  The Bay of Bengal has the thickest sediment anywhere on the ocean floor. Why is there so much sediment here? __________________________________________________________________________  ____________________________________________________________________________ ____________________________________________________________________________ c) North America – Rocky Mountains & Appalachian Mountains:  There is one river shown on your World Map that could carry sediment from the Rocky Mountains to the Gulf of California. What is the name of this river? ____________________  There is a very long river shown that carries sediment from the northern Rocky Mountains to the Mississippi River. What is the name of this river? _____________  Which river carries sediment from the Appalachian Mountains to the Mississippi? _____________  What is the maximum thickness of sediment in the Gulf of Mexico? _____________ km  What is the maximum thickness of sediment in the Gulf of California? ___________km  What mountain building process formed the Appalachian Mountains? ____________________________

2. (3 points) On the diagram below, showing the profile view from the Andes Mountains, across the Amazon Basin, and extending into the deep ocean, please indicate and label the following: The location where you find boulders (B) One location where you find clay (C) The location of the delta (D) The location of the flood plain (F) The location where the crust is made of granite (G) One location where you find living coccoliths (L) One location where you find calcite skeletons (S) The location where you find turbidites (T) The location where freeze/thaw happens (W) What is the depth of the continental shelf? ____________ meters 3. (2 points) Several different techniques were used during the 1800’s to determine the age of the Earth. One technique was to determine the volume of the ocean basins (km 3 ) and divide this by the rate that sediment is being delivered to the oceans each year (km 3 /yr, by rivers, glaciers, wind, etc.). This calculation indicates that the earth cannot be more than 3 million years old, or else the oceans would now be full of sediment! Why does this technique give an age that is much too young? (Note: there are at least 2 reasons that we discussed in class – either one will do) ____________________________________________________________________________ ____________________________________________________________________________ ____________________________________________________________________________ ____________________________________________________________________________ ____________________________________________________________________________ ____________________________________________________________________________ ____________________________________________________________________________

5 4 3 2 1 0 0.0 0.1 0.2 0.3 0.4 Li 5 4 3 2 1 0 0 200 400 600 800 Na 0 1 2 3 4 H 5 4 3 2 1 0 0 10 20 30 40 Be 0 20 40 60 80 Mg 5 4 3 2 1 0 0 1 2 3 4 5 Al 0 1 2 3 4 C Inorganic 0 100 200 300 Si 0 20 40 60 80 N NO3 0 1 2 3 4 5 P 0 100 200 300 O Dissolved O2 0 20 40 60 80 S 0.0 0.1 0.2 0.3 0.4 F 0 200 400 600 800 Cl 0 5 10 15 Ne 0 1 2 3 4 He 0 10 20 30 Ar 5 4 3 2 1 0 0.0 0.5 1.0 1.5 2.0 B 5 4 3 2 1 0 0 10 20 30 40 K 5 4 3 2 1 0 0 1 2 3 4 Rb 0 1 2 3 4 5 4 3 2 1 0 Cs 0 10 20 30 40 Ca 0 50 100 150 200 Ba 0 10 20 30 40 Sc 0 1 2 3 4 (57-71) Lanthanoid L 0.0 0.4 0.8 1.2 1.6 Sr 0 1 2 3 4 (89-103) Actinoid A 0 100 200 300 Ti 0 100 200 300 Zr 0 40 80 120 160 W 0 100 200 300 400 Y 0 2 4 6 8 Nb 0.0 0.1 0.2 0.3 Ta 0.0 0.2 0.4 0.6 0.8 Hf 0 2 4 6 Cr III VI Total 0.000 0.001 0.002 Ir 0.0 0.2 0.4 0.6 Pt 0.0 0.2 0.4 0.6 0.8 Au 0.00 0.03 0.06 0.09 Os 0 4 8 12 16 Zn 0.0 0.6 1.2 1.8 Cd 0.0 0.5 1.0 1.5 2.0 Hg 0 10 20 30 40 Ga 0.00 0.05 0.10 0.15 0.20 In 0 40 80 120 160 Tl 0 40 80 120 160 Ge 0 10 20 30 40 Sn Atlantic data 0 20 40 60 80 Pb 0 10 20 30 40 As Inorganic 0 1 2 3 4 Sb 0.0 0.2 0.4 0.6 0.8 Bi 0 1 2 3 4 Se IV Total VI 0.0 0.4 0.8 1.2 1.6 Te Total VI IV 0 1 2 3 4 Br 0 200 400 600 800 I (-I) Total 0 2 4 6 8 Kr 0.0 0.2 0.4 0.6 0.8 Xe 0 4 8 12 16 Ni 0.0 0.2 0.4 0.6 0.8 1.0 Fe 0 20 40 60 80 V 0 50 100 150 200 Mo 0 2 4 6 Cu 0 20 40 60 80 Co 0 20 40 60 80 Re 0.0 0.4 0.8 1.2 Mn 0 1 2 3 4 (Tc*) 0 1 2 3 4 Ru <0.05 pmol/kg 0.0 0.4 0.8 1.2 1.6 Rh 0.0 0.2 0.4 0.6 0.8 1.0 Pd 0 10 20 30 40 50 Ag 0 2 4 6 8 10 Rn* (222) 0 1 2 3 4 At* (219) Short-lived 0 2 4 6 8 Po* (210) 0 1 2 3 4 (Pm*) 0 1 2 3 4 (Cm*) 0 1 2 3 4 (Bk*) 0 5 10 15 Ce 0 4 8 12 Pr 0 10 20 30 40 50 Nd 0 2 4 6 8 10 Sm 0 1 2 3 Eu 0 5 10 15 Gd 0 1 2 3 4 Tb 5 4 3 2 1 0 0 20 40 60 80 La 0 5 10 15 Dy 0 1 2 3 4 (Cf*) 0 1 2 3 4 Ho 0 1 2 3 4 (Es*) 0 5 10 15 0 1 2 3 4 (Fm*) 0.0 0.5 1.0 1.5 2.0 2.5 Tm 0 1 2 3 4 (Md*) 0 5 10 15 Yb 0 1 2 3 4 (No*) 0.0 0.5 1.0 1.5 2.0 2.5 Lu 0 1 2 3 4 (Lr*) 0.00 0.02 0.04 (Am*) (241) 0.0 0.1 0.2 (Pu*) (239+240) 0 1 2 3 4 (Np*) 0 5 10 15 20 25 U* 0.0 0.1 0.2 0.3 Pa* (231) 0.0 0.1 0.2 0.3 Th 5 4 3 2 1 0 0.0 0.1 0.2 0.3 Ac* (227) 5 4 3 2 1 0 0 1 2 3 4 Fr* (219) Short-lived 0 2 4 6 8 Ra* (226) 5 4 3 2 1 0 0 1 2 3 4 5 mmol/kg µmol/kg nmol/kg pmol/kg mBq/kg (Element*) Concentration radioactive * ( ) artificial + } speciation Key: Vertical Profiles of Elements in the North Pacific Ocean (compiled by Y. Nozaki, 2001) 1 2 3 4 5 6 7 1A 2A 3A 4A 5A 6A 7A 8 1B 2B 3B 4B 5B 6B 7B 0 L A x

Classification of Profiles Note that t R is residence time, and [X] means the concentration of the element (the concentrations of accumulated elements (yellow) are constant with depth ; recycled elements (green) increase with depth ; scavenged elements (red) decrease with depth ) (Short residence time) (Medium residence time) (Long residence time) Low  High Low  High Low  High Surface