Day One
Lecture:
Latitude and Longitude, Bathymetric Maps and Profiles
Labwork:
Exercise 1: Latitude and Longitude
Exercise 2: Creating Bathymetric Maps & Profiles (create map)
Homework:
Exercise 3 & 4: Continental Margin & Southern California Bathymetry
Day 2
Lecture:
Review homework; The Continental Margin & Southern California Bathymetry
Labwork:
Exercise 5: Bathymetry of the Global Ocean
Homework:
Exercise 6: Direction and Distances
Bathymetric Maps: Coordinate systems
Maps have been used since ancient times to help people find their way about the land and sea. Until recently, travelers had to rely on the stars, a chart, and a compass to locate themselves. Today we use a location system that utilizes lines of latitude and longitude to locate places on a map.
Lines of latitude are also called lines of parallel, because they parallel the Earth’s equator. Latitude lines specify the angular distance north or south of the equator and are measured in degrees of arc. Thus, the equator is said to be at 0º latitude and either pole is at 90º latitude. Degrees are subdivided as follows: 1 degree = 60 minutes (or, 1º = 60’), and each minute = 60 seconds (or, 1’ = 60”). Hemisphere matters; latitudes north of the equator are denoted with an “N” for north, and latitudes south of the equator are denoted with an “S” for south. Using this system, Seattle, Washington is at 47º36’ latitude, and Adelaide, Australia is at 34°56'S latitude.
Lines of longitude, also called meridians, are also expressed as angular degrees and measure the distance 180° east or west from the prime meridian at Greenwich, England (0° longitude). As with latitude, longitudes are noted with respect to hemisphere; for example, Seattle, Washington is at 122º22’ and Adelaide, Australia is at 138°35'E longitude.
Figure 1: The graphic on the left shows the planes of meridians (also known as lines of longitude) bisecting the Earth and meeting at the poles. The graphic on the right shows the planes of parallel (also known as the lines of latitude) as they bisect the Earth at the equator and at about 30º N latitude.
Adapted from: Nathaniel Bowditch, American Practical Navigator, Hydrographic Office Publication No. 9, U. S. Naval Oceanographic Office, 1966
Exercise 1: Latitude and Longitude Name:
Objectives: The purpose of this exercise is to familiarize you with the latitude-longitude coordinate system.
Materials Needed:
1. Pencil / Pen
2. Ruler / Straight Edge
3. Computer with Internet access (for part C)
Part A
Directions: Using the World Map on the following page, find the latitude and longitude for the following locations:
A. New Orleans, LA, USA Lat: 30ºN Long: 90ºW
B. Durban, South Africa Lat: 30ºS Long: 30ºE
C. South Pole Lat: 90ºS Long: 0º
D. St. Petersberg, Russia Lat: 60ºN Long: 30ºE
E. Hangzhou, China Lat: 30ºN Long: 120ºE
F. Palu, Indonesia Lat: 0º Long: 120ºE
Part B
Directions: Using the Oceanography Base Map on the following page, plot the latitude and longitude for the following locations:
A. Reservation Point Lat: N 33° 43.2’ Long: W 118° 15.8’
B. San Pedro Canyon Lat: N 33° 38.8’ Long: W 118° 16.9’
C. Rock Pile Lat: N 33° 40.0’ Long: W 118° 13.9’
D. Relict Beach Lat: N 33° 41.1’ Long: W 118° 12.4’
E. Los Angeles River Lat: N 33° 45.2’ Long: W 118° 11.9’
F. Redondo Canyon Lat: N 33° 49.5’ Long: W 118° 26.5’
G. Redondo Knoll Lat: N 33° 40.5’ Long: W 118° 35.0’
H. Santa Monica Canyon Lat: N 33° 55.0’ Long: W 118° 37.5’
I. Point Dume Lat: N 34° 00.5’ Long: W 118° 48.7’
Part C
Directions: Go to any digital atlas or search engine and find the latitude and longitude for the following locations. Be as precise as you can.
A. Washington D.C., USA Lat: 38°53′ N Long: 77°02′ W
B. Kathmandu, Nepal Lat: 27°42′ N Long: 85°20′ E
C. Perth, Australia Lat: 31°58′ S Long: 115°49′ E
D. Rio de Janeiro, Brazil Lat: 22°54′S Long: 43°14′ W
E. Los Angeles, CA, USA Lat: 34°03′ N Long: 118°14′ W
F. Settlement of Edinburgh (hint: It’s not in Scotland, but it is a part of the United Kingdom!) Lat: 37º05’ S Long: ~12º21’ E
Exercise 2: Creating Bathymetric Maps & Profiles Name:
Objectives: to create a bathymetric map of the sea floor using spot elevation points
Materials Needed:
1. Pencils
Directions: The map shown below has survey spot elevations indicating the elevation of the sea floor at that location. Using a contour interval of 50 feet, construct a reasonable bathymetric map of this area. Start with the 50 contour line and proceed to the 350 line.
- Bathymetric Maps: The Continental Margin & Southern California Bathymetry
Continental margins are located at the edge of every continent, where the land meets the sea. There are four parts to the continental margin.
1. The Continental Shelf is a relatively flat region of land located just offshore from the continent proper. Continental shelves average 65-100 km in width and are formed by erosion and transport of sediment (primarily sands and muds)
2. The Shelf Break marks the end of the continental shelf and the beginning of the continental slope.
3. The Continental Slope extends from shelf break to rise and is the steepest part of the continent. Submarine canyons are major features of the continental slope. These undersea canyons are formed via two methods: River erosion and turbidity currents. Sediments on the continental slope are mostly muds, although sand, brought down from the continental shelf through the submarine canyons, can also be found.
4. The Continental Rise bridges the continental slope and the abyssal plain. Muds and coarser sediments “pile up” at the base of the continental slope; it is this pile of sediments that creates the continental rise.
5. The Abyssal Plain is also known as the ocean floor. It begins at base of continental rise and covers roughly 30% of earth’s surface (continents cover 29% of surface). Sediments are typically biogenous and terrigenous in origin, and are usually fine grained.
The abyssal plain is not a barren place. Numerous features are found on the ocean floor, including seamounts, guyots, ridges and rises, and deep ocean trenches
There are two basic types of continental margins: passive and active. The eastern seaboard of the U.S. is an example of a passive margin. Passive margins are not tectonically active. They tend to have continental shelves that are wide and relatively flat. Active margins, such as the western U.S. coastline, are tectonically active, and are characterized by a narrow shelf with irregular topography.
Continental shelf off the Southern California Coast is up to 90 miles from shoreline. Our shelf contains: basins, ridges, banks, islands, submarine canyons, and escarpments. These features are often given geographic names, such as Catalina Island or Fortymile Bank. The Southern California offshore terrain is similar to that onshore. For example, there are a series of NW trending valleys and ridges that roughly parallel the coastline from Los Angeles south to the Mexican border. North of Los Angeles to Santa Barbara, the valleys and ridge are aligned east-west, also paralleling the coast. Both are due to the tectonic activity of the Southern California region.
In 1996 the Pacific Seafloor Mapping Project surveyed the shelf and slope offshore Los Angeles, CA (between the 20 to 800-m isobaths) from Pt. Dume to the Paloes Verdes. In 1998 the project continued mapping to the south and surveyed the outer shelf, slope, and proximal basin off Long Beach and Newport. The two datasets were merged and regridded into a single database. The shaded-relief image of the land surrounding Santa Monica Bay was constructed using USGS 7.5 minute DEMs (Digital Elevation Models).
Name:
Exercise 3: Bathymetric Map & Profile Out To Edge Of The Continental Shelf
Objectives: to create a bathymetric map of the sea floor using spot elevation points
Materials Needed:
2. Colored Pencils
3. Red Pen
Directions: The Bights are a reentrant in the coastline. The Southern California Bight runs from Pt. Conception to the Mexican border and out to the Patton Escarpment. Refer to the map and the profile on the following pages to complete the project. Note that designation and colors are to go on bathymetric profile as well and do not use felt tip pens to color. Do not color so heavy that isobath lines cannot be seen or depth number cannot be read.
1. Color all land areas including the islands, light brown or orange.
2. Color all submerged areas between the shoreline, around the islands, and 100 meters water depth light blue.
3. Color all submarine areas between 100 meters and 500 meters water depth dark blue.
4. Color all area between 500 meters and 3,500 meters water depth (abyssal plain) purple or violet. Do not color the abyssal plain i.e. below 3,500 meters. The abyssal plain is the true ocean floor. All shallower areas on this map are part of the continent.
5. Note the location of following places or features on the map by placing their letter-number designation next to the name of the feature on the map. Do this with a red ballpoint pen so the designations are easily read. Be neat. It counts.
A. Basins - These are submerged valleys on the continent.
A1 – San Pedro Basin
A2 – Santa Monica Basin
A3 – Santa Barbara Basin
A4 – Catalina Basin
A5 – Santa Cruz basin
A6 – San Nicolas Basin
A7 – San Diego Trough
B. Islands - These are the tops of submerged mountain ranges on the continent.
B1 –San Miguel
B2 – Santa Rosa
B3 – Santa Cruz
B4 – Anacapa
B5 – Catalina
B6 – Santa Barbara
B7 – San Nicolas
B8 – San Clemente
B9 – Los Coronados
C. Ridges and banks - These are submerged mountain ranges on the continent.
C1 – Santa Rosa - Cortez Ridge
C2 – Tanner Bank
C3 – Patton Ridge
C4 – Cortez Bank
C5 – Thirty Mile Bank
D. Sea Mounts:
D1 – San Juan Sea Mount: This is an underwater volcano situated on the abyssal plain (the true ocean floor).
D2 – Abyssal Plain: This is the true ocean floor.
D3 – Escarpments: these are submerged linear cliff-like features that mark zones of faulting on the sea floor.
D4 – The Patton Escarpment: This marks the boundary between the true ocean basin (abyssal plain) and the continental shelf.
E. Geographic reference points
E1 – Pt. Conception
E2 – Santa Barbara
E3 – Ventura
E4 – Santa Ynez Mtns
E5 – Santa Monica Mtns
E6 – Los Angeles
E7 – Long Beach
E8 – Newport Beach
E9 – Santa Ana Mtns
E10 – Oceanside
E11 – San Diego
E12 – Mexican Border
E13 – Palos Verdes Peninsula
E14 – Huntington Beach
E15 – Malibu
E16 – Santa Monica
F. Map features
F1 – Scale
F2 – north arrow
F3 –line A-A'
Student Name ______/Date ______
Name:
Exercise 4: Bathymetric Map & Profile Out To Edge Of Continental Shelf
Objectives: to create a bathymetric map of the sea floor using spot elevation points
Materials Needed:
4. Colored Pencils
5. Red Pen
Directions: Refer to the map and the profile on the following pages to complete the project. Note that designation and colors are to go on bathymetric profile as well and do not use felt tip pens to color. Do not color so heavy that isobath lines cannot be seen or depth number cannot be read.
1. Color all land areas including the islands, light brown or orange.
2. Color all submerged areas between the shoreline, around the islands, and 100 meters water depth light blue.
3. Color all submarine areas between 100 meters and 500 meters water depth dark blue.
4. Color all area below 500 meters purple or violet.
5. Identify the following places or features on the map by placing their letter-number designation next to the name of the feature on the map. Do this with a red ballpoint pen so the designations are easily read. Be neat. It counts.
A. Basins - These are submerged valleys on the continent.
A1 –San Pedro Basin
A2 – Santa Monica Basin
A3 –Catalina Basin
B. Bays
B1 – Santa Monica Bay
B2 – San Pedro Bay
B3 – Emerald Bay
B4 – Alamitos Bay
C. Canyons
C1 – Dume Canyon
C2 – Santa Monica Canyon
C3 – Redondo Canyon
C4 – San Pedro Valley
C5 – San Gabriel Canyon
C6 – Newport Canyon
C7 – Catalina Canyon
D. Islands - These are the tops of submerged mountain ranges on the continent.
D1 – Catalina
D2 – Santa Barbara
D3 – Terminal Island (T1
E. Escarpments
E1 – San Pedro Escarpment
E2 – Catalina Escarpment
F. Knolls
F1 – Redondo Knoll
F2 – Avalon Knoll
F3 – Lausen Knoll
G. Geographic reference points
G1 – Santa Monica Mtns
G2 – Palos Verdes Peninsula
G3 – Catalina Isthmus
G4 – Santa Ana River
G5 – San Gabriel River
G6 – Los Angeles River
G7– San Juan Creek
G8– CSULA
H. Map features
H1– north arrow
H2 – Scale
H3 – Line A-A'
I. Cities and Towns
I1 – Laguna Beach
I2 – Newport Beach
I3 – Huntington Beach
I4 – Long Beach
I5 – San Pedro
I6 – Manhattan Beach
I7 – Santa Monica
I8 – Malibu
I9 – Hyperion
I10 – Avalon
J. Points
J1 – Point Dume
J2 – White’s Point
J3 – Dana Point
J4 – Point Fermin
Student Name ______/Date ______
Exercise 5: Bathymetry of the Global Ocean Name: