Geol. Bull. Univ. Peshawar, Vo1.30, pp. 41-51, 1997.

S. NAYYER AHSAN & I. H. QURAISHI Geological Survey of Pakistan, St-17, Block-2, ~ilistan-e-~auhar,Karachi, Pakistan.

ABSTRACT: Revolution in the earth sciences mainly due to the formulation of plate tectonic or global tectonic hypothesis in early 70's has provided better understanding of ore genesis and major tectonic settings. The hypothesis has given an impetus to the search of valuable economic minerals and rocks particularly in the Lasbela and Khuzdav districts of Baluchistan, Pakistan. Igneous, sedimentary and metamorphic rocks of Mesozoic and Cenozoic ages dominate the lithostratigraphic exposures. Mineralizations are found in different tectonic settings; chrom ite, copper, manganese, magnes ite in oceanic ophiolites and barite, lead, and zinc in the continental hot spots and rifts. Beside minerals the area has signifcant potential for marble, granite, basalt, brecciated serpentinized rocks (known coinmercially as "Black Zebra1?),quartzite, and variegated textured limestone suitable for use as building and decorative stones. Zinc-lead deposits at Duddar, Lasbela district, are now in the proving stage. Australian company (PASMINCO). Afer further exploration these may turn out to be a world class ore body.

INTRODUCTION limited scope of earning livelil~ood,unskilled and semi-skilled labour is easily available. The Lasbela-IUiuzdar districts with an area of Diverse rocks of igneous, sedimentary and over 750 sq, knl are two of the richest and most metamorphic origin of early Jurassic late geological complex regions of Pakistan and Tertiaiy ages together with structural holds vast prospects of metallic and non- con~plexitiesmake the area not only unique but metallic minerals, building and decorative challenging for research and investigation. stones. The small scale mining particularly for The area lies within the arid type of barite and manganese being carried out in the climatic region. Rainfall is scanty, hence most area since long, has increased many times since of the streams remain dry for most part of the the completion of RCD highway which passes year, only a few streams such as Nar River, through the area (Fig. 1). Now a days besides Kharak River, Nal River, Porali River, Winder barite and manganese, chromite, magnesite, Nai, Kharrari Nai, Gajri Nai etc. have perennial marble, variegated and textured rocks are also flow in some sections of their course. being mined/quarried. Vegetation is scanty. GEOLOGICAL SETTINGS The population of the Khuzdar and Lasbela districts is 5,00300 and 1,70,000 The geological setting of the Lasbela-Khuzdar respectively. The main occupation of the area is related to two major orogenies. The inhabitants is sheep and goat farming. Due to earlier relates to the break up of the super- GEOLOGICAL SETTINGS Turan block (Powel, 1979). The hdo-Pakistan plate collided with the Afghan and LU~ The geological setting of the Lasbela-Khuzdar microplates during late Cretaceous-~arl? area is related to two major orogenies. The Tertiary period. The collision led to the earlier relates to the break up of the super- development of folds and thrust belt and the continental Gondwanaland during late Triassic- obduction of ophiolitic complex at the western Jurassic period (Powell, 1979; Lydon, 1990,). boundary of the Indo-Pakistan plate. The folds The key processes operating at the time were divide an eastern calcareous facies zone of the rifting and extensional tectonics. The host foreland from western arenaceous zone of the rocks of the mineralization of lead-zinc hinterland (Fig.2). The Cenozoic flysch basin sulphides and barite deposits are sediments of the hinterland is taken as an accretion? within extensional tectonics (Ahsan, 1995). prism above the active subduction zone (Arthorton et al., 1982, Farhoudi & Kraig Following the break up of Gondwanaland 1979, Stoneley 1974 and White 1979). the Indo-Pakistan plate was separated froin the Fig. 2. Geology, structural features and distrihion of sediments in Lasbela-Khuzdar area (modified after Sarwar & Dejong, 1979).

MINERAL DEPOSITS settings and the main deposit types in the region are as follows: The Lasbela-Khuzdar area hosts a variety of mineral deposits which occur in a characteristic OCEANIC SETTINGS geological settings. In Fig.3 locations of the mineral showings have been marked. However, Chromite, Magnesite and Related Minerals many of the prospects have not been Peridotites and serpentinites are common both systematically investigated. The tectonic in the melange zone and the less disturbed ophiolite complex which often contains of Khuzdar where more than fifteen pods have lenticular/podiforrn or disseminated bodies of been identified (Fig.3) (x). These are being chromite. However, occurrence of commercial mined locally by open pit methods, The chromite deposits is not common in the deposits are fairly large and the annual ultrabasic rocks. The principal deposits are in production of chromite was 7698 tonnes in Sanaro, Baran Lak, Drakalo and Greshak area 1996-97.

EXPLANATION I lcigltl:

Triangtllnlcd

i\plirmi~~~alc

Rclorics (for minerals)

Fig. 3. MineraIdRocks occurrence location map of Lasbela and Khuzdar disbicts. Showings of magnesite and to a lesser systematically prospected using modern extent asbestos occur widely. However, only a concepts and exploration techniques. few are commercially exploitable. The promising deposits are in Baran Lak, Omach Manganese Deposits cross and Drakalo which are being mined Lenticular bodies of manganese oxides occur in locally. iron and silica rich layered (Jasperoids and siliceous red shales) horizons underlain by top The nickel-iron laterite is a localized layers of basaltic pillow lavas. Many development at the unconformable contact of manganese occurrences associated with the the ophiolites and the Late Tertiary limestone volcanic rocks, mostly of pillow lavas of beds. Its detailed study to prove its potential for basaltic/spilitic composition are recognized in economic exploitation. Lasbela-Khuzdar area. However, the most proinising localities are Khai-rari Nai, Bhamani Massive Copper Sulphide Deposits Dhoro, Siro Dhore, Sanjro -Dhoro, Kohan Jhal Massive copper sulphide prospects associated and Khabri Dhoro. These are being inined by with pillow lavas in the ophiolite complex have locals on small scale by open pit mining. The been identified in the Saap and Ann Dhoros annual production of chromite was 424 tomes localities of Lasbela district but these are of no only in 1996-97. economic value. Pillow basalt is wide spread in the areas under discussion with bright A brief description of these deposits is as possibility of some promising deposits of if follows:

Name of District, Size of mineralized zone Grade Reserves deposits coordinate and toposheet Kharrari Nai Lasbela, Two separate pods having Mn 42% 34,000 long tons 25'54'N 66" an exposed surface of 70 (Nasim, 1996) (Abbas, 1980) 45'E, 35 k/9. and 7 square meters respectively. Siro Dhoro Lasbela, Manganese in irregular Mn 36% 950,000 long 26'17'N 66" 33' veinsllenses range fiom (Nasim, 1996) tons E, 35,511 1. one to six inches in (Master, 1960) thickness. Sanjro Lasbela, 26" 28' Mineralization in Mn 15% 65,000 long tons Dhoro N 60" 26' E, 35 discontinous lenticular (Nasim, 1996) (Ahmed, 1969) 517. bodies having 0.5 km strike length and 1 to 5 meters thickness. Bhampani Lasbela, 26" 1 1' The ore is exposed in a MII 41% 5,800 (H.S.C., Dhoro N 66" 33'E, 35 vertical cut, made by open (Nasirn, 1996) 1960; 5/12. cut mining. It is almost Abbas, 1980) square in shape, with each side measuring about 6 meters. Gadani Lasbela, 26" Undetermined Mn 48% Undetermined Ridge 05'N 66" 34' E (Nasim, 1996) Dadi Dhoro Lasbela, 26" Undetermined Mn 3.5% Undetermined 05'N 66" 37'E (Nasim, 1996)

45 DEPOSITS RELATED TO CONTINENTAL ~opographically, the Gunga zinc-lead HOT SPOTS AND RIFTS deposit area is rugged with slopes ranging from 30' to 60" and at places steeper on escarpment zinc-~ead-~aheDeposits sides. The local elevation difference is up to Zinc, lead and barite occur widely as veins and 200 meters. replacement deposits in carbonate rocks. The most promising, however, is the stratiform The Gunga deposit is hosted by the lower massive deposit found in association with black part of the Early to middle Jurassic Anjira shales, mudstones/argillaceous limestones and formation of the Ferozabad Group. The host pyroclastichrecciated rocks. It is interpreted as rocks are predominantly black carbonaceous an exhalative sedimentary or Mississippi valley shale, siltstone and mudstone, subordinate type deposit (Ahsan et al., 1996). Duddar in limestone and local synsedimentary breccia and Lasbela and Gunga & Surmai in the Khuzdar conglomerate. districts are the three most important deposits. There are 20 other prospects/occurrences such The inineralization is stratiform, strata- as Sekran, Malkhor & Ranj Laki in Khuzdar bound and open space filling. district and Mithi Nai, Kanrach and Dham Jal in Lasbela district already identified in the Outcrop of the ore mineralization region which require further exploration. associated with rugged hogback rides, is over 1,200 meters long and is distinguished as a silic The exploitation of zinc-lead well depend goassan. This gossan is composed of leached upon the reserves found by PASMINC. It is and silicified calcareous siltstone and yellowish stated that over 14 m tone with a combined Zn- brown-red oxides of iron. The metal content in Pb grade of 14-16% has already been proved. the silicic gossan varies from 3-4% Pb and Zn. However, barite is being mined. The annual production of barite was 2,827 tomes in 1996- 97. Based on the surface geology and information obtained from 14 drill holes, two The characteristics of the important zinc- main mineralized zones were delineated and lead mineral deposits/prospects are established in the Gunga area: summarized below: 1. The upper mineraIized zone is dominantly Gunga barite. Sphalerite and galena are

The Gunga deposit (Fig. 3) is located at about concentrated in the lower part of the barite , 3.5 km south-southeast of the village Gunga at bed. The barite bed lies between the I lat.27'44'~ and long.66'33'~. It is accessible hydrothermally altered shale in the hanging from Khuzdar by traveling 11 km to the wall and the highly silicified rocks in the southeast on an unmettaled road. The distance foot wall. The thickness of barite bearing from Khuzdar to Karachi and Khuzdar to horizon varies from a few meter to over 70 Quetta is approximately 350 km and 270 km meters (Jancovic, 1986). The lead-zinc respectively. RCD Highway connects both the mineralization in the barite s evenly cities with Khuzdar. distributed and confined to a narrow zone. !1 The lower lead-zinc mineralized zone has On the basis of drill hole data, total ore lenses and irregular veins formed along a reserves are estimated at 30.51 million tones of brecciated zone. The mineralization is which 22.7 million tons are sulphide and the dominantly stratiform relative to the balance 7.81 million tons are oxide ores. The enclosing rocks but in places epigenetic as lead-zinc ore has a grade value of 0.66% Pb, fiactureiopen space fillings. The 3% Zn and 7.4 glt Ag (JICA, 1989). mineralized bodies mostly contain over 6% Zn and 1.5% Pb and at places exceed 10% Duddar (Jancovic, 1986). The Duddar deposit is located on the eastern flank of the Mor Range at lat.26'05'~ and The mineralized bed in it lower horizon is 66'50'E. Road distance from Karachi 200 km composed of dissemination and thin layers of is (about 92 krn upto Khurkhera on Karachi- the sulphide minerals. Bela section of the RCD Highway and 108 km on the unmetalled Khurkhera-Kanrach road The estimated reserves (Pb-Zn combined) which detours north from the main highway). are as under: The Duddar mineralization occurs in two Proven6.5milliontons separate exposures known as Duddar North and Probable.3.0 m tons Duddar South. These exposums are 258 and a Possible 3.3 m tons (Jankovic 1983) 274 meters long with an average thickness of 10 meters. Its extension hrther north of Surmai approximately 700 meters in strike length The Surmai prospects are located at about 1 km under alluvial cover has been delineated by south of Ganga deposits (lat.27'43'17"~ and drill holes. long.66'3 1'27"). However, the mineralization at Surmai occupies a lower stratigraphic position. The mineralization is stratiform, hosted by It is accessible fiom Gunga by a fair weather interbedded siltstone, mudstone and shale jeepable track. sequence of Anjira formation, The hanging wall of the sulphide ore contains about 30 There are three distinct mineral showings meters thick barite with traces of marcasite. along an uplifted zone. These are called Sunnai I, I1 and I11 extending discontinuously fiom north to south for approximately 1 krn. These The sulphide mineralization below the showings are hosted in limestone of Loralai exposed barite ore body is consists of formation. These are considered to be laminated sphalerite, marcasite and galena. Mississippi Valley (MV) type which is a combination of replacement along the bedding The detailed drilling program (completing plane of the host rocks and fissure filling. The a total of 63 holes, almost 18km of core) has bedding replacement type is seen in Surmai I outlined an indicated mineral resources of 6.86 and I11 while the fissure filling type is seen in Mt grading 1 1.43% Zn and 2.10% Pb (Allen et Surmai 11. al., 1994). Other promising Occurrences The characteristics of the other promising occurrence in the area are summarized below:

Name of Dist., site, Type of Grade Size of Reserves References Prospects coordinates and mineralization Mineralized zone toposheet West Khuzdar, Sekran Stratabound Zn- Surface showing not JICA Sekran hill, E27O 52' and vein 3.15% 1.5 km x 0.5 km. estimated (1 987) N66O 52, 3545 types. P b- The mineralized 0.02% zone ranges in thickness from 1 to 5m. East Khuzdar, Sekran -do- ND Surface showing -do- -do- Sekran Hill, E27'15' 400m x 200m, N66" 33' 35-115. Bedded ore bodies, range in thickness from 31-11 to 5m Ranj Laki Khuzdar, -do- ND Surface showing Possible Jankovic malkhor, E66O 300m x 90m. The Zinc- (1 983) 26' 45" N27'52' mineralized zone lead= 3,3 JICA 30', 35-119. shows cl~angein mill. t. (1 987) meineralization from thick to massive bedded & open space filing Kundni- Lasbela, -do- Ba 40% The Fairly ah sat^, Dharn Jhal E66'3 1 ' to ZnG0 mineralization as large 1994 area E66"3 1 ' and % Pb discontinuous barite N26O 1 7' to N26O 2% exposures/bodies deposit. 25' 35-Jll I. is traceable for about 5krn in between Kundni and Dharn jha1 Kanrachzi Lasbela, E66' -do- Ba 45% The Barie Ahasn, bro 50' N26O 04', Zn max mineralization is more than 1991 & Dhoros 35-Jll I. 0.7% Pb discontinuous and 3 3,3 50ton 1994 rnax 5% restricted to a nes 700m long and an average 2.Sm wide zone Mithi- Lasbela, Mithi -do- Zn-2.7% The development Fairly Ahsan Arrara Nai, E66'26' Pb-1.6% of gossan is large (1 989) Dhoros N26" 08', 35- Ba-38%. widespread as deposits J/8, discontinuous of barite exposures traceable for about 7km in strike lenght and range in thickness from lm to 6m.

48 MISCELLANEOUS DEPOSITS stone. However, at present there is no mining activity. Industrial rocks 4. Basaltldiabase: Exposures of basalt are Igneous rocks widely distributed in the ophioiite compelx of the region. The fresh and easily Granite accessible exposures (e.g. in Gajri Nai) are Colnmercial use of the term granite is being mined locally. Basalt is used for dbnsiderably broader than geologic use. In building aggregates, riprap etc. A modern industry, the term refers to true granite, granite application is for high-density aggregate in gneiss, and the intermediate members of the the concrete shields of nuclear reactors. granite-gabbro series. Notwithstanding the broad use of the term most of the granite of commerce has composition in the range that Small amount of basalt is mined cut includes true granite and granodiorite (Bates and polished as dimension/decorative 1969). The important deposits known from the store. This rock is co~nrnerciallytermed as area under discussion are: "black granite".

1. Plagiogranite, also called trodjomite is 5. Ultramafic rocks: Sheared variety of exposed as a solitary outcrop on the RCD serpentine later cemented by calcareous Highway about 2km north of the Khabbar mateial is present as allochthons within the Jhal (35 I/8). It is pale white to white, hard melange zone. It is locally quarried for use and resistant to weathering. Pistachio as polished slabsltiles. This rock is green epidote grains, are sporadically cominercially termed as "Black Zebra" or distributed in the rock giving an appealing "Red Zebra". look. This granite can be used in facing of building and other decorative purposes. Metamorphic rocla Marble/recrystallized limestone: Blocks of 2. Pink Granite is present as an exotic block Recrystallized limestone of unidentified age are, within the melange zone. The main being mined for a long time. The blocks are outcrops of one square km is located at usually of smaller dimensions and exposed in about 5 krn south of Wad. There are few the melange zone. The main problem of these other small exposures in Wad tehsil. They blocks is their shattered nature and difficult are resistant to cl.iemica1 and physical accessibility. However, private sector has been weathering. The deposit is minable, working on these small deposits according to however, the main problem is the removal the demand in the market. This limestone is of outer weathered part of the rock. After usually pale white to light dirty white and cutting and polishing it results a pleasing normally used in mosaic tile industry. look.

3. Cumulate Gabbro: Exposures of cumulate Besides the above mentioned variety, the gabbro are present along the RCD highway relatively much less disturbed beds of grey and in the vicinity of Baran Lak and Ornach dirty off white marbles ranging in thickness Cross. In cumulate gabbro, orientation of froin few centimeters to more than one meter ~ldspar,_slivinedppxen* ifctearly +ti-~xposediwthevkirrity-of SunmoVfilagep seen. If cut across and polished the rock (35 J/5) of Khuzdar district. It is also being displays a beautiful look. This can be very quarried in big blocks and transported to suitably used as building and decorative Karachi for cutting and polishing. Orthoquartzite: The orthoquartzite The huge deposits of overall varieties of exposures found along Gajri Nai (35 518) in limestones in the area appear to have a Bela tehsil is being quarried for quit some time good reserves of high quality raw material for use as flux in the steel mills. for the establishment of huge cement industrial complex in the area for a good economic return. Sedimentary Rocks Limestone: A limestone is a valuable The reserves of good quality decorative geological resource in the region. Depending stones are huge and transport charges upon its colour, texture, composition and would not be very high due to easy hardness it is being mined for different uses. approach to the sites, cheap labour and proximity to the industrial and port city of The Limestone of Jhakker Group Karachi. (Paleocene-Eocene) which is argillaceous in nature and low in magnesium has the ideal So far as accessibility is concerned, the composition as raw material for cement. It is sites are not very far off from the RCD available in large quantities with no overburden and within 50km from Karachi. One cement Highway which passes through the ,area factory namely the "Attock cement" is already under investigation and which connects the in production and the other namely "Galadari biggest industrial area of Karachi of Cement" is being established in Hub tehsil of Pakistan. Lasbela district. The exploitation of the rocks can be Limestones of Parh and Jhakker Groups economical and a good source of foreign exposed near Karachi (toposheet no. 35 W12 exchange earning. & 16) are the main target of the mine owners for use as decorative stones. The limestone is Acknowledgments: The first author thanks typically porcellanous and sublithographic. It is Mr. Shabbir Ahrned Baloch of INDUSTRIAL variegated and in the referred area light pink, MINERAL SYNDICATE for providing latest light green and pale white varieties dominate information about the mining activities in the which exhibit lake polish. The beds are studied area. characteristically regular, smooth faced and 0.5 to 1.5 meter thick which help in easy mining. REFERENCES Rocks are excavated as blocks which are transported by trucks to factories in Karachi for Abbas, S. G., 1980. Kharrari Nai, Bhampani cutting, polishing and marketing. Dhoro and Porar Dhoro Manganese Deposits, District Lasbela, Baluchistan, Pakistan: Geol. Surv. Pakistan I.R. no. CONCLUSIONS AND DISCUSSIONS 122. Ahmed, Z., 1969. Directory of Mineral Politically the area is peaceful, the people Deposits of Pakistan. Geol. Surv. Rec. are poor, hospitable and looking forward Vol. 87.

AlisaniXN, lY8T Geology ZidrnineEl~g~of~- zinc-lead-barite . prospects, Lasbela The occurrence of metallic sulphides of District, Baluchistan, Pakistan. Geol. Sum. zinc and lead and sulphate of barium in Pakistan, I.R. no. 4 18. Early-Middle Jurassic carbonate and Ahsan, S. N., 1995. Petrogenesis of Shirinab ciastic rocks of the area appear to offer Formation, Lasbe la-Khuzdar area, high potential for the country. Baluchistan, Pakistan. Unpubl. Ph.D. dissertation, Department of Geology, Baluchistan, Pakistan (unubl.). University of Karachi. Japan International Co-operation Agency Allsan, S. N. & Khalil A. Malik, 1996. A (JICA), 1 989. Final report on co-operative genetic model for zinc-lead mineral mineral exploration in Khuzdar area of deposits, Lasbela and Khuzdar Districts, Baluchistan, Pakistan (unubl.). Baluchistan, Pakistan. GEOLOGICA, Val. Lydon, J. W., 1990. Report on examination of 2, NO.I, Geoscience Lab., Islamabad. Zn-Pb-Ba deposits of the Lasbela-Khuzdar Allen, R. Mark & Anwar, J., 1994. Geological belt, Baluchistan, Pakistan. Unpublished setting of Duddar zinc-lead deposits: An UNDTCD Mission Report, 90. exploration model for the Lasbela-Khuzdar Master, J. M., 1960. Manganese showings of belt. Proc. secod SEGMITE International Lasbela District, Pakistan. Geol. Surv. Conf., Karachi, pp. 64-71. Pak. I.R. no. 13. Arthurton, R. S., Farah, A. & Ahmed, W., Sarwar, G. & Dejong, I<. A., 1979. Arcs, 1988. The late Cretaceous Cenozoic oroclines, syntaxes: the curvatures of History of Western Baluchistan, Pakistan nlountain belt in Pakistan in Farah, A, and the northern margin of the Makran Dejong, K.A., eds., Geodynamics of subduction complex in Leggett, K. Serelny Pakistan, 34 1-349. edt. Trench Fore Arc Active Plate Margin. Sillitoe, R. H., 1975. Metallogenic evolution of Geol. Soc. Loond. Spec. Pub. No. 10, 373- a collisional mountain belt in Pakistan (a 385. preliminary analysis): Geol. Surv. Bates, L. Robert, 1969. Geology of the Pakistan, Record v. 34, 15. industrial rocks and minerals, Dever Stoneley, R., 1974. Evolution of the continental Publication Inc., New York, 23-58. margins boundings a former southern Farhoudi, G. & Karig, D. E., 1977. Maluan of Tethys. In Burk, C.A. and Darlte, C.L. Iran and Pakistan as an active arc system: (eds). The Geology of Continental Geology, 5, 664-668. Margins, Springer-Verlag, New York, Hunting Survey Corporation Limited (H.S.C.), 889-903. 1960. Reconnaissance Geology of Part of Nasim, S., 1996. The Genesis of Manganese West Pakistan, A Colo~nbo Plan Co- Ore Deposits of Lasbela, Baluchistan, operative Project Report: Toronto, Pakistan: Unpubl. Ph.D. dissertation, Government of Canada, 458-46 1. Department of Geology, University of Jankovic, S., 1983. Exploration and Karachi, 2 12-262. preliminary evaluation of the lead-zinc- Powel, C. McA., 1979. A speculative tectonic barite deposits at Gunga, Khuzdar district, history of Pakistan and surroundings: some Baluchistan, Pakistan: UNDTCD/UNDP constraints from the Indian Ocean in Final Report Pak/79/01 6, 1 60. (Unpubl.) Farah, A. and Dejong, IC.A., (eds.) Jankovic, S., 1986. The mineral association and Geodynamics of Pakistan,. Geol. Surv. genesis of the lead-zinc-barite deposits at Pakistan, Quetta, 5-24. Gunga, Khuzdar district, Baluchistan, White, R. S., 1979. Deformation of the Makran Pakistan. Geol. Surv. Pakistan, Rec. continental margin, in Farah, A. and vLXXI, 12. Dejong, I<. A., (eds.) Geodynamics of Japan International Co-operation Agency Pakistan, Geol. Surv. Pakistan, Quetta, (JICA), 1987. Report on co-operative 295-304. mir~alexploration in Khuzdar area of