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Geologic Survey of Kapoeta County:

Report on the Reconnaissance Fieldwork in Kapoeta County

Prepared By:

John Ariki, John Caesar, and Patrick Legge, members of the Geology Working Group of the Strategic Analysis and Capacity Building (SACB) Activity in Agriculture and Natural Resources

July 2002 Supported by the USAID-USDA PASA in collaboration with the University of Missouri, Tuskegee University and the University of Maryland Eastern Shore

This report is made possible by the generous support of the American people through the United States Agency for International Development (USAID). The contents are the responsibility of the authors and do not necessarily reflect the views of USAID or the United States Government.

International Agriculture Programs University of Missouri

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Table of Contents

Table of Figures ............................................................................................................II I - Introduction ..............................................................................................................1 1- Background .............................................................................................................1 2- The Study Area........................................................................................................1 3- Objectives of the Fieldwork ....................................................................................3 4- Constraints...............................................................................................................4 II - Results of the Fieldwork .........................................................................................5 1- Geology ...................................................................................................................5 i- Regional Geology ................................................................................................5 2- Geomorphology.......................................................................................................6 3- Hydrology................................................................................................................7 4- Petrology (Rocks of the area)..................................................................................9 5- Tectonic and Volcanism........................................................................................11 6- Mineralization .......................................................................................................12 7- Mining activities in the area ..................................................................................15 III ­ Conclusion and Recommendations ...................................................................16

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Table of Figures

Figure 1: Simplified map showing the study area ...........................................................2 Figure 2: Livestock Market in Narus...............................................................................3 Figure 3: Narus Market - most of the items are imported from Kenya ...........................3 Figure 4: Tobacco sold in the market in Narus ...............................................................3 Figure 5: Typical forms of intrusions. A dyke extending about 8 km ...........................5 Figure 6: The Dyke of small Naita Hill north of Narus ..................................................6 Figure 7: Vegetation west of Lopua - note the change in soil and vegetation and the Didinga Hills at the background..............................................................................6 Figure 8: Landscape and typical Vegetation in the study area ........................................7 Figure 9: River Narus flooding with runoff water from the Didinga Hills .....................7 Figure 10: River Narus 10 minutes later .........................................................................7 Figure 11: Soil erosion near Narus town .........................................................................8 Figure 12: The water hole (Lorus) in Narus ....................................................................9 Figure 13: Basalt and lava flow in River Loyoro ............................................................9 Figure 14: Typical weathering in the Lava flow ...........................................................10 Figure 15: Thick Lava beds exposed at R. Loyoro........................................................10 Figure 16: Alluvial Sediments exposed at R. Narus......................................................11 Figure 17: Alluvial Sediments underlying the thick Soil cover ....................................11 Figure 18: Pillow Lava near Narus................................................................................12 Figure 19: Quartz vein in Lava rocks ............................................................................13 Figure 20: Geode filled with a layer of quartz crystals from the study area ................13 Figure 21: Various types and colored Quartz and Ilmenite (black) ..............................13 Figure 22: Calcite crystallizing in the weathered Lava flow.........................................13 Figure 23: Petrified Wood showing the original wood structures.................................14 Figure 24: Petrified Wood from another perpective......................................................14

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I. 1.

Introduction Background

The geology team is one of the six Strategic Analysis and Capacity Building (SACB) in Agriculture and Natural Resources working groups assigned with the task of studying the geology and mineral resource potentials of the New Sudan. The New Sudan, especially Southern Sudan, is one of the least geologically investigated areas of the world. Apart from a few exploration activities in search of gold by the Belgian Mineral Exploration Team (BMET), mica and marble by the then Regional Government, and oil by Chevron and its successors, very little effort has been exerted to understand the geology of the region. Specifically, for the last two decades nothing has taken place except the controversial exploitation of oil in Upper Nile Region by the GoS and the mining of gold in Southern Blue Nile. Due to the civil strife in Southern Sudan it has been impossible to carry out any research to systematically study the geologic and mineral resources potential of the New Sudan. In light of this situation, the Geology Working Group launched its first ever fieldwork in April 2002. The authorities on the ground were very supportive of the work of the geology team. The Commissioner for Industry and Mining was present in Narus at the time of the fieldwork and contributed greatly through advice and discussions over the mineral resources ­ especially gold in the New Sudan. His observations as a hobby geologist in the field of gemstones were also very valuable. Similarly, members of the local population were good sources of information on types, quantities and uses of minerals, especially in those areas not visited by the team. 2. The Study Area

The area studied during this fieldwork is located in the southern part of Kapoeta County, which extends from near the borders with Kenya in the south up to Lolim in the north (see map). The Toposa ethnic group inhabits the area, which has been under the control of the SPLM since 1987.

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Figure 1: Simplified map showing the study area

Narus is the largest town in the area and is the administrative headquarters of Kapoeta County (before the recapture of Kapoeta town). Other towns and villages include Nadapal, Lolim, Napotpot and Nakodok. Over 5,000 people inhabit Narus, the majority of whom are students from neighboring Budi and Torit counties as well as from Kakuma refugee camp in Kenya. The rest of the population is composed of internally displaced persons (IDP), the staff of the New Sudan Council of Churches, SRRA and the Diocese of Torit (DOT), which run all the schools in the area, and a few indigenous people. The Toposa live in their respective villages near Narus and throughout the areas controlled by the SPLM. The people living in the study area are mainly pastoralists and depend very little on subsistence agriculture. The nature of soil and climate does not encourage extensive 2

agricultural activities except in limited areas around River Kuron, where it is possible to grow crops most of the year. They trade with neighboring Kenya where they sell their livestock and gold for other needed commodities such as salt, soap and clothes. Other item such as grains and tobacco come from Budi and Torit counties.

Figure 2: Livestock Market in Narus

Figure 3: Narus Market - most of the items are imported from Kenya

The area is dominated by thick thorny bushes and various species of acacia (Ipoto, 1983). Larger trees are concentrated along the riverbanks and on top of the hills where deep-seated fissures contain some water even in the dry season.

Figure 4: Tobacco sold in the market in Narus

3.

Objectives of the Fieldwork

This reconnaissance fieldwork was intended to be the beginning of a series of field activities to survey and produce geological maps of the areas under study. The main objective was to develop a general overview of the geology of the area and to identify areas of interest for any future mineral prospecting and exploration. The secondary objective was to review topographic maps from the 1930s and 1940s and to match them with the surface features of the day. This step is necessary because topographic maps are generally updated every five to ten years to take into account human developments, i.e., infrastructure or new buildings, or natural activities that affect the topography such as earthquakes, landslides, etc. 3

Another objective of the study was to gather local knowledge, views, practices and beliefs about minerals and natural resources in general and to determine how consistent they are with accepted norms and practices of environmental conservation. This will be used in the preparation of strategies and materials for community sensitization and education on how to sustainably utilize and conserve these resources for the benefit of all generations. 4. Constraints

Any survey activity is never free from constraints. Due to the fact that no prior needs assessment has been conducted, the team spent some time organizing and searching for alternatives which in turn restricted the actual geological work. The following are some of the difficulties faced by the team throughout the fieldwork. (i) Security: At the time of the survey, many of the areas of interest were near the frontlines of the conflict and were not accessible. In view of this, the county authorities advised the team not to go near these areas as it could pose high security risk to the team. Furthermore, some parts of area of study are known for cattle rustling activities between the Toposa and the Turkana tribes. Due to the unpredictable nature of these raids it was unadvisable to carry out any work in those areas.

(ii) Rains: Rains were a major constraint to the study. The black cotton soil covering the areas of the fieldwork makes mobility impossible once it had rained. Furthermore, during times of rain, the normally dry streams and rivers become flooded. Due to the absence of bridges across these rivers, vehicles as well as pedestrians can only cross to the other side after the rains have stopped and the level of water has gone down. This, however, often takes three to twelve hours depending on the amount of rainfall in the upstream areas. (iii) Communication Facilities: Communication was one of the serious problems faced by the team. Throughout the period of the fieldwork it was difficult to receive or send any information to Nairobi about the progress of the work in the field. Similarly, any information sent was received too late to act on in time. On one occasion, a team member had to travel to Lokichoggio in order to be able to communicate with Nairobi. The delay in receiving equipment for the fieldwork was mainly attributed to lack of communication facilities and the delay in receiving the relevant information.

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II. 1.

Results of the Fieldwork Geology

Intensive geological investigation was carried out on an area of approximately 60 sq. km extending 15 km to the west of Narus town, five km to the south and east, respectively, and 25 km to the north (see fig.). Most of the outcrops were investigated, samples were collected and the outcrops were documented with photographs.

Figure 5: Typical forms of intrusions. A dyke extending about 8 km

The geology of the investigated area appears at first glance to be monotonous, with a flat terrain that is interrupted by many hills of variable forms and altitudes. This, however, appears not to be the case when the rock formations and the tectonic features are critically viewed. The following are some account on the geology of the area of Narus town and the neighboring areas. Regional Geology The geology of the area is similar to that found in northern Kenya and western Ethiopia. It is representative the western limit of the volcanic terrain that extends from Ethiopia and continues southwards to northern Kenya. The western side of the region borders the granitic and metamorphic rocks that constitute the basement zone that begins with onset of the Didinga Hills, Dongotona and Imatong Mountains. It is believed to be part of the Eastern Rift Valley, which underwent uplift and volcanic activities during the Tertiary Era (65 ­ 1, 6 Ma).

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Figure 6: The Dyke of small Naita Hill north of Narus

The geologic structures, which predominantly assume east­west and north­south orientation patterns, seem to confirm some patterns known from the eastern African Rift system. 2. Geomorphology

The study area can be divided into three geomorphologic units: a) Mountains: The Didinga Hills and Mogila Mountains are between 1400m and 2700m above sea level.

Figure 7: Vegetation west of Lopua - note the change in soil and vegetation and the Didinga Hills at the background

b) Dykes and plugs: These features consist of hills that rise sharply from the plains. Heights vary between 800m and 1000m. c) Plains: Areas below 700m. 6

Figure 8: Landscape and typical vegetation in the study area

The area studied has never been properly mapped. Most of the observed topographic features were not recorded on the topographic maps from the 1930s and1940s which were referred to during the fieldwork. The present drainage patterns, for example, do not match with those on the map. The current course of the River Narus is no more what it is on the map. Furthermore, the names of some hills, villages and rivers are not the same as those given to them in the topographic map. 3. Hydrology

Surface Water The hydrology of the area is dominated by seasonal streams and rivers, which generally flow from the southwest to the northeast. The catchment area for the water is the Didinga Hills in the west, where the Nakodok, Narus and Loyoro rivers originate. These rivers discharge into the swampy area northeast of Narus where all of them end.

Figure 9: River Narus flooding with runoff water from the Didinga Hills

Figure 10: River Narus 10 minutes later

During the rainy season, these rivers are flooded, depending on the amount of rainfall upstream, with huge amount of water. The flow of water, however, stops shortly after the rains have stopped leaving behind the wet riverbed and some small water ponds 7

where the surface morphology permits. The soil cover in the area is very often carried away by the flowing water leading to the soil erosion and creation of new streams or change of the course of the river. No permanent surface water is observed in the area except the waterhole in Narus and some springs in the area.

Figure 11: Soil erosion near Narus town

Ground Water Ground water is the main water used in the area for drinking and irrigation of gardens during the dry season. The highly fractured volcanic formations are very good reservoirs for the ground water. These rocks underlie the sedimentary cover and are undoubtedly the source of the ground water in the area. The sedimentary alluvial infill of gravel, sand and silt can also be considered as aquifers, though these are often constrained by limited storage capacities and erratic recharge. No data have been acquired during this fieldwork about the hydraulic properties of these aquifers. The team, however, intends to collect relevant data from the drilling companies operating in the areas of Southern Sudan Ground Water Quality There is no observed concern about the quality of water in the area during the fieldwork. The population of the area lives entirely from the ground water for their domestic consumption and for their livestock. No data could be acquired on the quality in regards to the chemical properties, e.g., salinity and heavy metal concentration. It should, however, be noted that little variation in the taste of water occurs locally. These variations need to be confirmed through chemical analysis of the water in question. The Waterhole of Narus A waterhole is located near the river in Narus town that bears water throughout the year. The occurrence of the waterhole was not investigated by the team but can be explained as being either a local exposure of a water bearing formation or the obstruction of flow and migration of ground water due to a change in rock property, e.g., reduced porosity or permeability of the rock at that particular point. The water level is hardly affected by water that fills the nearby river, and it does not spill over its bank. The fact that the water does not drain away makes its quality questionable as far 8

as contamination is concerned. This and others springs reported on tops of some hills need thorough geological investigation to understand their origins, mode of formation and structure.

Figure 12: The water hole (Lorus) in Narus

4.

Petrology (Rocks of the Area)

The rocks of the study area are predominantly of volcanic origin. Basaltic rocks constitute most of the hills, which intruded into the thick banks of the lava flow that covered the entire area. Alluvial sediments also cover parts of the area and are mainly found in the southern part of the area (exposed along River Narus). The basaltic rocks found on the hills and exposed at Loyoro River are very hard and dense. They display different rock characteristics than those of the lava. These dense rocks are stratigraphically younger than the lava flow. The team geology group has so far no data on the age of these rocks.

Figure 13: Basalt and lava flow in River Loyoro

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While younger basaltic rocks are dark-gray to black in their fresh form, they give colors ranging from yellow to red. These colors reflect the chemical composition of these rocks. The yellow represents a bivalent iron oxide (limonite, goethite), and the red color, the trivalent variety of the iron oxide (hematite). The lava stratum is highly fractured and grayish-green in its fresh form. The rock is very susceptible to chemical weathering giving colors ranging from gray, whitish to brown. Some outcrops show concentric and pillow structures. Quartz and calcite often crystallize in the joints and fractures of lava formation but never in the basalt. Evidence of extensive chemical weathering of the rocks can be observed in the riverbeds.

Figure 14: Typical weathering in the Lava flow

Figure 15: Thick Lava beds exposed at R. Loyoro

The alluvial sedimentary formation found in the area is overlying the lava formation. The extent of this sedimentary formation could not be determined. It is, however, exposed along the banks of the Narus River, the only place where they can be observed. It is made up of conglomerate, sand and silt intercalations. The gravel and pebbles are made up of mainly well-rounded granitic, gneissic rocks, which undoubtedly explain their place of origin west of the area of investigation.

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Figure 16: Alluvial Sediments exposed at R. Narus

Figure 17: Alluvial Sediments underlying the thick Soil cover

5.

Tectonic and Volcanism

A major lava flow ­ probably submarine ­ seems to have covered the whole area. The subsequent intrusions, however, came to surface through apparently deep-seated fractures as can be witnessed by the ridge-like shapes of some of some hills in the area. Most of the hills are actually volcanic dykes that stretch north to south or east to west with dykes exposed at the ridge or centers of these hills. Some hills have rounded outlines and are composed of boulders of rock material similar to those of the dykes. The origin and direction of the lava flow needs further investigation although some observation suggests a northeast to southwest flow. Some structures (probably a lava front) show a northwest trend. Two major faults trending north­south were observed at Lotupwamurio (10 km north of Narus) and Lopua (9 km west of Narus) hills respectively. Both are dipping with 80° towards the west.

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Figure 18: Pillow Lava near Narus

Most of the fractures found in the lava formations do not show any preferred orientation. The joints between the blocks of the dense basaltic rocks at Loyoro River, however, seem to break the general rule and assume more or less southeast to northwest and southwest to northeast trends. The tectonic activities associated with the formation of the African Rift have left evidence on the general landscape and the rocks of the area. Divergent boundaries cause rifting, in which broad areas of land are uplifted or moved upward. These uplifts and faulting along the rift result in rift valleys. The African Rift Zone -- part of the Great Rift Valley ­ extends from Syria to Mozambique and out through the Red Sea. In these areas, volcanic eruptions and shallow earthquakes are common. There are still a lot of tectonic activities going on; this is evidenced by the earthquake occurrences recorded in the whole Equatoria region.

6.

Mineralization

The minerals observed by the team during the fieldwork include several varieties of quartz and calcite. Both are found crystallized in fractures, as aggregates or as debris on the ground. Quartz and Chalcedony The origin of this mineralization is believed to be from the ground water circulating inside the fractures of the host rock. Opal (SiO2.nOH) precipitates in pores of sedimentary rocks or in fractured igneous rocks through loss of water and later crystallizes into chalcedony and quartz.

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Figure 19: Quartz vein in Lava rocks

Figure 20: Geode filled with a layer of quartz crystals from the study area

In this situation, the water carrying soluble SiO2 might have penetrated the fractures of the volcanic rocks and SiO2 was then precipitated as opal. Later chalcedony and quartz crystallized from opal. The former becomes colored with green or red colors due to impurities such as iron, aluminum, and copper that is washed out from weathered host or other rocks. Opal can be the source of the colored chalcedony and quartz in the study area. One observation that seems to confirm this theory is that a relatively high population of quartz and chalcedony is encountered north of Narus town. This implies that the flow of the water carrying soluble SiO2 was predominantly north to south or northwest to southeast and saturation with SiO2 decreased before it was finally exhausted near the borders with Kenya.

Figure 21: Various types and colored Quartz and Ilmenite (black)

Figure 22: Calcite weathered Lava flow

crystallizing

in

the

The different forms of chalcedony and many of the crystalline varieties of quartz are used as gemstones and other ornamental materials. The many colors and the high luster of polished chalcedony render it valuable for brooches, necklaces, and other ornaments. Pure rock crystal is used in optical and electronic equipment. In the form of sand, quartz is used extensively in the manufacture of glass and silica brick and is also 13

used in cement and mortar. Ground quartz is used as an abrasive in stonecutting, sandblasting, and glass grinding. Powdered quartz is used in making porcelain, scouring soaps, sandpaper, and wood fillers. Large amounts of quartz are used as a flux in smelting operations. Almost all natural high-grade quartz crystal, which is an important raw material in the electronics industry, is imported from Brazil, the only country with large deposits of the mineral in commercial quantities. Agate This is a rock or mineral composed of layers of quartz, sometimes of different colors. The composition of agate varies greatly, but silica is always predominant. Agate can be polished to a high gloss and is often used for ornamental purposes and has different technical applications due to its chemical resistance. Apart from colored chalcedony, agate is also found abundant in the study area. Petrified Wood Petrified wood is a wood that is completely transformed into a stone but maintained its original cell structure. This occurs when the organic materials overlain by sediments are dissolved through the circulating waters and later replaced by minerals especially chalcedony. Petrified wood is found in Arizona in the United States, Egypt, the Patagonia region of Argentina, and now in Southern Sudan. Apparently, a whole forest near the study area was transformed into rocks through geological processes. The type of the trees as well as the time in which the petrification took place is yet to be established through the analysis of the samples.

Figure 23: Petrified Wood showing the original wood structures

Figure 24: Petrified Wood from another perspective

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Petrified wood, though of little industrial importance, is of archaeological significance when found in large quantities (e.g., Petrified Forest National Park in Arizona). Gold According to the information from local people gold is found in three main areas, namely Napotpot and Naita in Kapoeta County and near Boma town. Gold is reported to be extracted from hard rocks or panned from alluvial deposits in riverbeds. The "gold belt" is said to extend from the Southern Blue Nile region through the Boma Plateau over Napotpot and on to the Democratic Republic of the Congo. This information, though plausible, lacks any known geologic findings. According to the information from the local people, the gold in the area near Kapoeta is panned from alluvial sediments from or near the riverbeds. The yield varies depending on the season. Rainy seasons are said to have higher yields (up to 5gm/day). So far there is no reliable information about the gold bearing rocks. The source rock of the gold, however, appears to be in the areas where the rivers originate ­ in the Didinga Hills. Through a thorough systematic sampling and analysis it will be possible to understand and document the nature of the gold deposits in the area. Other Minerals Some samples brought from the neighboring Budi and Torit counties were presented to the geology team. These were identified as pyrite and ilmenite/magnetite. Ilmenite (FeTiO3) and magnetite (Fe2O3) are the main sources of titanium and iron, respectively. Ilmenite is the chief source of titanium dioxide, TiO2, which is used in paint pigments and welding-rod coatings and in the manufacture of the metal titanium. Pyrite, also called "fool's gold", is composed of iron sulfide (FeS2), the most common sulfide mineral. It is a common mineral in sedimentary rocks and also occurs in igneous and metamorphic rocks. It is often associated with coal formations and sometimes occurs in association with gold or copper. Pyrite is not mined as an iron ore, because of the difficulty of removing the sulfur. It is used mainly in the commercial production of sulfuric acid. Pyrite, which is said to contain some gold, is being mined in the areas of their occurrence in Torit and Magwi counties; there is reportedly a market for this mineral in neighboring Uganda. 7. Mining Activities in the Area

Kapoeta County is one of the areas of New Sudan known for gold occurrences. The local population has been familiar with the activity of panning for gold for a long time. In the early 1970s and in the beginning of the 1980s, they bartered gold for food items brought to them by the northern Sudanese traders. Panning for gold was considered less lucrative than cattle keeping and, therefore, was of limited interest for the Toposa. Other factors that might have affected the mining of gold and other minerals are the beliefs and myths associated with them. The people in these areas as well as other areas of Southern Sudan believe that there are some super-natural powers and demons 15

controlling some of the mining sites. Some gold-rich sites have to be cleansed first by offering a goat each time they need to access them to deter any evil and health problems that may eventually affect them. With the exposure of the population to the rest of the country, gold acquired some more importance, though not as much as that of cattle. Those who owned few or no cattle practiced gold mining in order to buy more cattle. Today, there are increased mining activities. The gold mined is mainly sold in Kenya. The practice of small-scale mining may have adverse impacts on environment if no proper training is provided to the miners. So far, there are no reports on the effect of gold mining on the environment. Mining in the study area appears to be men's domain. No women provided any information or expressed interest in rocks or minerals. This could be attributed to the social structure of the local population where certain activities and responsibilities are clearly defined. III. Conclusion and Recommendations

The fieldwork has been a success despite the constraints mentioned previously. It has been an eye-opener for the local population and authorities, who were unaware about the presence of minerals other than gold. Years previous some foreign geology specialists came to the area and took large amounts of rocks and stones under the pretense of sending them for tests to determine their market value. These specialists were never heard from again, however. The experience of this team shows that there are more minerals in the areas of the New Sudan than have been reported up to now. The occurrence of ilmenite/hematite and the gold-bearing pyrite, for example, have never been documented before. The lack of equipment during the fieldwork made it impossible to uncover minerals beyond that visible to the naked eye. Additional tools, electronic equipment and personnel would help to detect radioactive minerals that might be buried in shallow depths or associated with some rocks in the area. In order to effectively carry out survey activities in future, there will be need to: 1. Work with the drilling companies operating in the areas to access information about the rocks in the subsurface. NGOs could also provide data and geological information uncovered while drilling boreholes. 2. Training and education of the local population on the importance of mineral resources and on environmental awareness. 3. Provision of a small laboratory for initial testing and preparation of samples for further analysis. 4. Foster co-operation with other scientific institutions through participation in conferences and workshops.

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