Physical Geography Laboratory Manual Section Name EXERCISE 49 PROBLEMS-PART II T
ID: 304905 • Letter: P
Question
Physical Geography Laboratory Manual Section Name EXERCISE 49 PROBLEMS-PART II The following questions are based on Map T-16, the "Corpus Christi, Texas" topographic map (scale 1:250,000; contour interval 10 meters) and Figure 49-9, a satellite image you can view b going to the Lab Manual website or by scanning the QR code for this exercise. Padre Island is a prominent barrier island south of Corpus Christi, Texas (27 17'22'N, 97°24'21'w) I. What is the highest elevation sthown on Padre Iiland? 2. (a) What is the most likely origin of Baffin Bay? meters (b) What is the evidence for this? 3. (a) Does it appear that "Laguna Madre" (between Padre Island and the mainland) is filling with sediment? What is the evidence of this? What are the likely sources of this sediment? (b) (c) EXERCISE 49 PROBLEMS-PART III-GOOGLE EARTHTMExplanation / Answer
1. Elevation of Padre Island is 17 meters
2. a) Padre Island formed from offshore shoals, with later growth aided by spit accretion. After a history of shifting, abandonment and reestablishment by storm breaches, many tidal inlets were slowly closed.
b) During a sea- level fall between 120-20 ka the creeks cut an incised valley between 18-24m deep at the present coastline (Behrens, 1963) and up to 30 m deep on the shelf (Eckles et al., 2004). The incised valley has partially filled with Holocene sediments following a sea- level rise over the last 20ky. In addition to black mud facies and terrigenous clastic facies, Baffin Bay also contains coated grains, ooids, surpulinid wormtube reefs, stromatolites, and evaporates.
3. a) Yes
b) The wind-tidal flat surface at Laguna Madre is constantly changing.
C)after a history of shifting, abandonment and reestablishment by storm breaches, many tidal inlets were slowly closed. Short islands were joined to form today's longer islands. Wind, wave and current action continue to rework and shape the island.