UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY PROJECT REPORT Pakistan Investigations (IR)PK-27 RECONNAISSANCE OF THE GEOLOGY AND ORE MINERALIZATION IN PART OF THE CHAGAI DISTRICT, PAKISTAN \ OPEN FILE REPORT This report is preliminary and has not been edited or reviewed for conformity with Geological Survey standards or nomenclature Prepared under the auspices of the Government of Pakistan and the Agency for International Development U. S. Department of State 1975 RECONNAISSANCE OF THE GEOLOGY AND ORE MINERALIZATION IN PART OF THE CHAGAI DISTRICT, PAKISTAN, 1964 by Raymond H. Nagell U. S. Geological Survey CONTENTS Page ABSTRACT.................................................. 1 INTRODUCTION.............................................. 2 Location and accessibility........................... 2 Climate and vegetation. ........................ »...... 4 Scope of the report.................................. 5-6 Previous work........................................ 7 Acknowledgments...................................... 8 GEOLOGY................................................... 9 Physiography......................................... 11 Igneous rocks........................................ 12 Sinjrani Volcanic Group*........................ 13 Chagai intrusions*.............................. 16 Dikes........................................... 18 Koh-i-Sultan Volcanic Group ..................... 19 Age of igneous rocks............................ 19 Sedimentary rocks.................................... 20 Humai Formation*........... 1 .................... 20 Rakshani Formation*............................. 22 Early Recent deposits ........................... 22 Recent deposits................................. 23 Structure 23 Structure of the Chagai Hills................... 25 CONTENTS (Cont.) Page ECONOMIC GEOLOGY........................................... 29 Mineral deposits of the western Chagai Hills.......... 31 Copper........................................... 31 Iron............................................. 40 Travertine marble................................ 40 Summary.......................................... 53 Mineral deposits other parts of the Chagai District... 54 Sulphur.......................................... 56 Travertine marble................................ 58 Iron............................................. 62 Copper........................................... 65 Lead and zinc.................................... 70 REFERENCES................................................. 72 ii ILLUSTRATIONS PLATE Page plate 1. Geologic map of the western Chagai Hills...........In pocket FIGURES Fi§ure 1* Index map showing mineral localities in Chagai District, Quetta Division, and the area covered by Plate 1........................................... 3 2. Sketch map showing distribution of igneous rocks and the trend of the major orogenic axis in the Chagai District...................................... 10 3. Sketch map of the Shambi Dik copper deposits near Zargan Nala.....................................33 4. Sketch map of the Patkan copper deposit near Amuri Nala...........................................36 5. Lower contact of the Juhli travertine marble deposit..............................................42 6. Sill-like sheet of travertine marble cutting monzonite............................................ 44 7. Hematite and calcite replacing green translucent travertine marble....................................45 8. Vuggy layer in travertine marble.....................46 9. Horizontal layers of travertine marble in contact wi£h a sloping bedrock surface.......................48 10. Juhli travertine marble depo'sit showing active quarry bench......................................... 50 11. Sketch map showing the quarry area of the Juhli travertine marble deposits...........................51 12.. Sketch map showing inferred copper-bearing zone in the Bandagan copper-magnetite deposit.............66 iii TABLES Page ble 1. Travertine marble reserves in part of the Juhli quarries............................................ 52 2. Travertine marble reserves at Mashki Chah........... 59 3. Summary of travertine marble reserves in Chagai District............................................ 61 IV RECONNAISSANCE OF THE GEOLOGY AND ORE MINERALIZATION IN PART OF THE CKAGAI DISTRICT, PAKISTAN, 1964 by Raymond H. Nagell U.S. Geological Survey ABSTRACT The Chagai District of the Quetta Division is in the north­ western part of Pakistan. % Igneous activity during the Himalayan orogeny included the extrusion of horizontally layered andesites of the Cretaceous Sinjrani Volcanic Group, emplacement of monzonitic stocks of the Cretaceous Chagai intrusions, and the extrusion of flows and tuffs of the Koh-i-Sultan Volcanic Group during the Pleistocene. The western Chagai Hills remained a stable area only intermit­ tently submergent during the Himalayan orogeny. Marine limestones are interlayered with the Sinjrani Volcanic Group. The Mirjawa- Dalbandin trough formed south of the Chagai Hills and received conglomerates and sandstones of the Cretaceous Humai Formation, and sandstones, shales, and limestones of the Paleocene Rakshani Formation. Doming and faulting are the major structural features in the western Chagai Hills; open folds developed in the sedimentary units to the south in the Mirjawa-Dalbandin trough. Mineral deposits in the Chagai District include solfataric sulphur l^^osits on the southern flank of Koh-i-Sultan volcano and scattered travertine marble (locally called onyx marble) deposits; they are related i: i-'-r.e to Pleistocene volcanism. Production from the sulphur deposits is about 20 tons per day of ore containing as much as 50 percent sulphur. T..e .~>:e is shipped by rail to a refinery in Karachi. The travertine T.arble is quarried in blocks of 16 cubic feet or more. About 20 tons v per day are shipped to Karachi for trimming and export. Hydrothermal and contact metasomatic base metal and iron deposits tor-ed during intrusive activity in the Cretaceous and Eocene. They are widely distributed through the Chagai District, but nearly all are :oo small to oe of economic importance. The Bandagan chalcopyrite- n^netite has been partly prospected by diamond drilling. Ore reserves indicated by drilling are 32,000 tons of 0.5 to 1.0. percent copper ore. Additional prospecting may increase the quantity and quality of reserves. INTRODUCTION Location and accessibility Tne Chagai District of the Quetta Division is in the northwestern r-'-r. or Pakistan; it is bordered by Afghanistan to the north and '-in to che west. The general region that includes the Chagai District * still known as Baluchistan, although it no longer is a political . An all-weather road and a standard gauge railroad traverse length of the Chagai District (fig. 1) linking the city of Quetta, Pakistan, with Zahidan, Iran. , I '*=-XNDlfong Kolol ', V .--.,,^7// Boro WESTERN CHAGAI HILLS. X T Travertine niartilo dopo&it X $ Sulphur X tu Copper X ft Iron deposit X Pb lead ami /me U«pokit Area covered by pUte 1 »r 25 0 25 50 75 100 MILES I I I I I I i i Figure 1. Index map showing mineral localities in C.hagai District, Quetta Division, and the area covered by Plate 1. The western part of the Chagai Hills (pi. 1) lies in the north- cantral part of the Chagai District. The area covered by plate 1 is bounded by Afghanistan on the north, parallel 28°N. on the south, and by the meridians 63° and 64°E. Access to the western Chagai Hills is by road from Quetta to mile- post 284.25. From this point on the main road, a tract passable for trucks and four-wheel-drive vehicles winds north across the stony and sandy desert and enters Amuri Nala at the south edge of the Chagai Hills. The road follows the nala north to Johan Karez, Shah (Sor) Karez, and to the levy post, Patkok, on the Afghanistan border. Because of the rugged terrain, access to areas away from the road is limited to foot and camel trails and boulder-strewn nalas in the hill area. The stony desert south of the hills is traversible in most places by four-wheel- drive vehicles. The sandy desert in the northwestern part of the area shoxvn on plate 1 is not readily accessible to wheeled vehicles. Climate^ and vegetation Rainfall in this arid desert varies from year to year but averages about 4 inches annually. Some years may pass with no measurable rain­ fall. Summer temperatures exceed 100°F., and in winter, fall below freezing, The term "Nala" means gully, arroyo, or dry wash. The term "Rud" is also used in this sense and appears on topographic maps of the area. Scope, of the report N'ur.erous showings of base metals have been reported from the Chagai District, especially in the area covered by this report. The associ­ ation of these deposits with the largest continuous exposure of igneous recks in Pakistan was assigned for investigation. The investigation was a joint activity of the Geological Survey of Pakistan and the U.S. Geological Survey, under the auspices of the Government of Pakistan^and "he U.S. Agency for International Development. The area included in plate 1 was examined from October 1963 through January 1964. All showings of copper, iron, and travertine marble were studied and mapped. Contacts between the Sinjrani Volcanic Grouper Chagat intrusions,* and Humai* and Rakshani* Formations were mapped on aerial photographs. Aerial photographs were used because suitable maps of Sufficiently large scale and accuracy were not available; the Survey of Pakistan is currently compiling