The gross compositional character of the coarse fraction of each sample was 

 examined under the the binocular microscope/ and the constituent particles were 

 identified and counted. Heavy mineral separations were made using tetrabromoethane 

 (S . G . 2.95), and heavy minerals were identified and counted under the petrographlc 

 microscope . The light minerals were mounted, stained with sodium cobaltlnitrlte to 

 distinguish the feldspars, and similarly counted. Clay mineralogy was determined 

 qualitatively using standard x-ray diffraction techniques. The carbonate mineralogy 

 also was determined on total samples by an x-ray diffraction technique. All samples 

 were visually scanned for dolomite after treatment with dilute acid and use of a 

 dolomite stain . 



III. REGIONAL SETTING 



A. Coastal Geography 



The Arabian Sea Is the northern arm of the Indian Ocean located between the 

 Indian and Arabian Peninsulas. The area of study is the northern portion of the 

 Arabian Sea bounded to the south by approximately 19* north latitude (Fig. 1). 

 The northern Arabian Sea Is bordered by India, Pakistan, and Iran to the east and 

 north, and the Al Batina and Oman Coast to the west . Major seaport cities border- 

 ing the area include Bombay, India, and Karachi, Pakistan. 



The largest river in the area is the Indus; Its modern delta is located south of 

 Karachi . This river drains a large portion of the Indo-Gangetic plain and extends 

 well into the Himalayas. The Narbada and Tapti rivers of India are smaller than the 

 Indus and empty into the Gulf of Cambay . These rivers drain the mountainous region 

 of central India, including the Vindhya and Satpura ranges. South of the Gulf of 

 Cambay, drainage Is eastward, and no Important streams reach the sea . Drainage of 

 the coasts of Iran and western Pakistan Is accomplished by a few relatively small 

 rivers . The Arabian coast contributes virtually no significant drainage to the north- 

 ern Arabian Sea . 



Physiographic provinces in this area are shown by Lobeck (1945) and are also 

 Illustrated by Heezen and Tharp (1965b) . Along the Indian coast, south of and In- 

 cluding part of the Gulf of Cambay, the area is bounded by the Western Ghats. 

 These mountains rise abruptly from the sea to an average elevation of 3,000 feet. 

 The Saurashtra, or Kathiawar, Peninsula Is characterized by a relatively wide coast- 

 al lowland . The Indus River Delta area is low and swampy. The remainder of the 

 Pakistan and Iran coast consists generally of a narrow coastal lowland which rises 

 quickly to a plateau averaging 2,000 feet In elevation with Individual peaks ranging 

 up to 7,000 feet . The Arabian coast bordering the study area is generally rugged 

 and precipitous, but south of Ra's Al Hadd the relief becomes more subdued . 



