Louisiana State University LSU Digital Commons LSU Historical Dissertations and Theses Graduate School 1963 Physical Geography of the Las Bela Coastal Plain, West Pakistan. Rodman Eldredge Snead Louisiana State University and Agricultural & Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_disstheses Recommended Citation Snead, Rodman Eldredge, "Physical Geography of the Las Bela Coastal Plain, West Pakistan." (1963). LSU Historical Dissertations and Theses. 857. https://digitalcommons.lsu.edu/gradschool_disstheses/857 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Historical Dissertations and Theses by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. This dissertation has been G4—160 microfilmed exactly as received SNEAD, Hodman Eldredge, 1931- PHYSICAL GEOGRAPHY OF THE LAS BELA COASTAL PLAIN, WEST PAKISTAN. Louisiana State University, Ph.D., 1963 G eography University Microfilms, Inc., Ann Arbor, Michigan PHYSICAL GEOGRAPHY OF THE LAS BELA COASTAL PLAIN, WEST PAKISTAN A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Geography by Rodman Eldredge Snead B.A., University of Virginia, 1953 M.S., Syracuse University, 1955 June, 1963 ACKNOWLEDGMENTS I wish to thank the many people who have aided in the completion of this study. I am particularly grateful to Dr. Richard J. Russell, Dr. William G. Mclntire, Dr. David D. Smith, William P. Agster and the staffs of the Coastal Studies Institute of Louisiana State University, Meteorological Department of the Government of Pakistan, and of the Geogra­ phy Departments of the University of Karachi and the Univer­ sity of Sind. This study was conducted by the Coastal Studies Institute of Louisiana State University under the auspices of the Geography Branch, Office of Naval Research, Contract Nonr 1575 (03), Task Nonr Order NR 388 002. During the summer and fall of 1959 William P. Agster, graduate student in geology, Louisiana State University, accompanied the writer in the field. During the fall and winter of 1960-1961 Dr. David D. Smith, who was,at that time, field investigator for Coastal Studies Institute, Louisiana State University, assisted in field research. For aid in consulting documentary material, I extend thanks to the Pakistan National Scientific and Technical Documentation Centre, Karachi and A. K. Sherwani, Assistant Meteorologist, Meteorological Office, Karachi, Pakistan. Many acknowledgments must be offered for assistance and hospitality extended by the Pakistanis in the Las Bela area and in Karachi. The United States Embassy and American Aid Programs loaned equipment for field work. Special thanks are to be given to S. M. Niazi, Under Secretary to the Government of Pakistan, and Haji Mohd. Siddiq, Deputy Com­ missioner of Las Bela, for approval to carry out field work in the Las Bela area. The following Pakistan Government officers offered most helpful aid; S. N. Naqvi, Director of the Meteorological Office, Karachi; Abdul Q. Afghan, Executive Engineer, Pakistan Works Department Roads Division; M. Rahimullah Qureshi, Central Fisheries; Agha G. Hussain, Central Fisheries; M. H. Khan, Geological Survey of Pakistan; Robert Raikes, Water and Power Development Authority of Pakistan; Mohammad Usman, Customs Post, Sonmiani. Of great assistance in the field were members of the local community and universities, particularly: Abdul Rauf Khan, geomorphologist, University of Karachi; Dr. Mushtaqur Rahman, Department of Geography, Sind University; Dr. S. Z. iii Hasnain, Department of Botany, University of Karachi; Mohammad Tasnif, botanist, Pakistan Council of Scientific and Industrial Research, Karachi; Ghulan Qadar Sherzaman, Sonmiani businessman. For aid in identification of plant specimen, I wish to thank: Dr. Jason R. Swallen, Head Curator, Department of Botany, Smithsonian Institute, Washington, D. C. For help in identification of shell specimens, thanks to: Mrs. W. S. S. van der Feen-van Benthem Jutting, Zoolo- gisch Museum, Amsterdam; Dr. Fritz Haas, Chicago Natural History Museum; A. R. Ranjha, Zoology Department, D. J. Science College, Karachi. iv TABLE OF CONTENTS PAGE ACKNOWLEDGMENTS........................................... ii LIST OF TABLES ............................................viii LIST OF FIGURES.......................................... ix LIST OF PLATES .......................................... xi ABSTRACT ........... xiii CHAPTER I. INTRODUCTION .................................... 1 • Utilization of the coastal plain by humans and animals ......................... 7 The fishing settlements.................... 10 Fishing...................................... 12 Animal life.................................. 13 II. WEATHER AND CLIMATE............................. 19 Reasons for the desert ...................... 20 Temperature.................................... 24 Relative humidity............................. 29 Precipitation.................................. 30 Winds.......................................... 36 S t o r m s ........................................ 37 Western depressions. ..... ........... 37 Eastern depressions......................... 38 Arabian Sea cyclones ...................... 40 Theory of dessication......................... 42 III. VEGETATION AND S O I L S ........................... 46 Main divisions of natural vegetation .... 47 v CHAPTER PAGE Central plain............................... 48 Riverine vegetation......................... 49 Mountains and foothills.................... 49 Swamp vegetation ........................... 51 Dune and beach ridge vegetation............ 52 Disturbed vegetation ......................... 55 Vegetation disturbed by man and animals.................................... 55 Soils.......................................... 57 IV. GEOLOGIC FRAMEWORK ............................. 63 Geological history ........................... 64 The highlands.................................. 71 Eastern mountains........................... 71 Western mountains........................... 72 Marine invasion of the Las Bela area .... 74 Uplift along the Makr5n Coast................. 7 7 V. PLEISTOCENE TERRAIN............................. 81 Alluvial gravels ............................. 85 D a t i n g ...................................... 86 Pleistocene on the east side of the coastal plain............................... 86 Seaward cliff of the main sand accumulation ............................. 90 Minor Pleistocene sand accumulations . 92 Pleistocene on the west side of the coastal plain............................... 97 VI. CENTRAL PLAIN.......................................100 R i v e r s ........................................... 104 The effect of m a n ..............................107 Silt d u n e s .......................................109 Slranda L a k e .................................... 110 Origin of the l a k e ........................... 112 Marine invasion of Siranda Lake.............. 114 VII. COASTAL ZONE .......................................117 Mountainous coast................................118 vi CHAPTER PAGE The offshore area..............................119 The headlands.................................. 119 Pocket beaches ............................. 121 Inner Dunes.......................................123 Miani Lagoon .................................... 127 Mangroves.......................................131 Beach ridges and spits ......................... 134 Beach ridges on the west side of the coastal plain........................... 135 Beach ridges on the east side of the coastal plain........................... 138 Block diagrams of the coastal plain. 140 The beach z o n e .................................. 144 SonmiAni Harbor.................................. 147 CONCLUSION ..................................................154 PLATES ...................................................... 157 SELECTED BIBLIOGRAPHY.......................................171 APPENDIX A .................................................. 178 APPENDIX B .................................................. 191 APPENDIX C .................................................. 192 VITA ........................................................ 194 vii LIST OF TABLES TABLE PAGE 1. Absolute Maximum and Minimum Temperature in °F for Selected Stations.................... 27 2. Diurnal Variation of Mean Relative Humidity for Karachi (Period: 1928- 1947)............................................. 31 3. Annual Rainfall in Inches (1931-1959)........... 32 4. Variability of Rainfall (Selected Stations in Baluchistan and Sind, West Pakistan) ................................. 34 5. Mean Number of Rainy Days........................ 35 6. Vegetation Sequence in the Las Bela A r e a ............................................. 54 7. Desert Soils of the Las Bela Area............... 58 viii LIST OF FIGURES FIGURE PAGE 1. Location M a p ..................................... 3 2. Coastal Types..................................... 4 3. Recorded Earthquakes and Location of Mud Vents in Southern Baluchistan............. 6 4. Average Annual Rainfall.......................... 21 5. Intertropical Convergence Zone ................. 22 6. Average Rainfall and