Geological Maps

Geological maps are topographic maps that show the layers and structures of the earth's crust. The world's first geological map is dated back to the year 1644 in France. Geological maps are prepared using various divisions of geology such as petrology, metallurgy, geology, structural geology and paleontology (fossils).

The Geological Survey Department in YGSMRB is responsible for the preparation, collection and storage of geological maps containing basic information on various types of rocks and their formational status. Geological survey projects have gained a considerable weight since the 1970s with the issuance of geological maps for several areas and in various scales. Yemen had also worked, prior to the reunification of Yemen in 1990, on the preparation of unified maps for the country that included geological, topographic, hydrological, magnetic and radioactivity measurement maps along with seismic and volcanic maps using scales of 1,000,000:1, 500,000:1, 250,000:1 and 100,000:1. In accordance with the activity of the geological survey, mineral and hydrological maps of Yemen were issued in a scale of 1,000,000:1 from 1993 to 1994.

Since the year 2000, YGSMRB has been designing geological maps on a scale of 100,000:1 and thematic maps on 50,000:1. A table summing up all the maps prepared until December 2010 is presented hereunder.





الخــرائــط الجيــولــوجيــة مقياس رسم 1: 100,000 (2010م)



تابع الخــرائــط الجيــولــوجيــة مقياس رسم 1: 100,000 (2010م)




دليل الخرائط الجيولوجية مقياس رسم 1: 100,000



Thematic Maps

A thematic map is a topographic map depicting a purpose or a theme it was compiled for such as appraisal of water basins, spotting the sites and numbers of drilled wells and defining some natural characteristics such as the water electric conductivity. Some maps are also prepared to show the urban development of a specific city or to study and assess the environmental impact in the quarries areas…etc. The Geological Mapping Department in YGSMRB has drawn thematic maps on a scale of 50,000:1 in cooperation with the German Federal Institute for Geosciences and Natural Resources (BGR) involving 12 quality thematic maps for Sana'a basin as follows:

1. A geological map;
2. A hydrological map;
3. Wells spotting map;
4. Water electric conductivity map;
5. Nitrates water ratio map;
6. Dams positioning map;
7. A map of the pollution around the water treatment plant;
8. The sites of rock breakers around the city of Sana'a;
9. A map of hospitals and healthcare units.
10. A map of the potential forestation sites, and
11. A map on hydrocarbon pollutants.

What are the benefits of geological and thematic maps?

Gold• Exploring natural resources like minerals, energy and water sources.
• City planning, definition of the sites of construction projects, settlements, roads and dams and assessment of the areas geologically to avoid potential natural disasters such as landslides, where there is a risk of such disasters due to combination of geological features.
• Spotting the proper sites for wastes disposal.
• Determining the potential sites that are vulnerable to natural hazards such as earthquakes, volcanoes and rock slides and consequently minimizing the physical and human losses that are likely to result from such hazards.
• With regard to water, the geological maps provide information that may improve the efficiency of water drilling sites by providing information on the stratigraphic sequence of rocks and their relation to geological structures.
• As far as agriculture is concerned, the geological map contributes to improving agricultural efficiency by identifying areas with volcanic soils that contain beneficial minerals for agricultural crops and identifying areas with poor with lime-rich soils.
From the above, it becomes obvious that the geologic and thematic maps are important for various applications. The following parties are likely to be the key beneficiaries of the geological and thematic maps:
• Ministry of Public Works and Roads.
• The General Authority for Lands, Surveys and Urban Planning.
• The General Authority for Environment Protection.
• Companies that wish to invest in the mining sector.
• Ministry of Water and Environment
• Ministry of Agriculture and Irrigation.
Geological Maps