Unveiling Earth's Ancient Secrets: A Geological Exploration of Naukluft Park in Namibia

Naukluft Park, located in the south-central part of Namibia, is a geological wonder, showcasing some of the most intricate geological structures in the region. Within this natural wonder is the Naukluft Nappe Complex (NNC), a testament to the dynamic processes that shaped the Earth during the formation of the supercontinent Gondwana.

Figure 1. Geological map of the study area with inset of the Naukluft Nappe Complex.

Figure 2. Satellite image of the Naukluft Nappe Complex (highlighted in red).

Key Geological Features

The Naukluft mountains, which form a klippe of the NNC, bear witness to the last stages of the Damara Orogeny, that took place approximately 500-550 million years ago. This orogeny was produced by the convergence of two continents that resulted in the formation of mountain belts forged from shallow water marine deposits. The NNC appears as a thrust and fold belt, comprising distinct layers of rock, with the "sole dolomite" as the lowermost stratum. Identified by (Korn & Martin, 1959) as the gritty dolomite, this layer represents a geological boundary, separating the older sediments of the nappe complex from the younger sediments of the Nama Basin below.

Figure 3. Field photographs of folded cap layers in Naukluft Park.

Figure 4. Outcrops showcasing parasitic fold found in the limbs of the bigger Folded cap dolomite and phyllite units.

Geological History

The sediments that constitute the NNC originated in a Neo-Proterozoic foreland basin, forming an integral part of the Southern Margin Zone (SMZ) of the Damara Orogen. Notably, these geological formations were later displaced approximately 50-100 km from their original location, a dynamic process described by Gray et al. (2008); Miller et al., 2009). This motion highlights the ever- changing nature of Earth's crust and the enduring impact of tectonic forces.

Distinctive Rock Formations

Among the remarkable features within the thrust sheets of the Naukluft Park is the ptygmatic folded cap carbonate, an iconic rock found in the Blässkrans Formation. This unique geological structure, studied by Morris et al. (2018) and Morris & Grotzinger (2023), unveils a fascinating chapter of Earth's history, providing information on the environmental conditions and geological events that led to its formation. It contains nice structures such as fold, faults and boudins that are found in different lithologies in the Naukluft.

Figure 5. Thrust faults found at the contact between the dolomite and the phyllite rock in the Blässkrans Formation.

Figure 6. Boudin structures in a mylonite rock which are sausage like structure normally formed by extension.

In summary, Naukluft is an area of great geological importance, with complex and well-preserved geological structures. It is a testament to the wonders of the Damara Orogeny, with its distinctive feature of older rock strata overlain by younger formations. This unique geological juxtaposition within Naukluft encapsulates a pivotal chapter in the broader narrative of Earth's history, making it a noteworthy repository of the Damara Orogeny's enduring legacy.

References

• Gray, D. R., Foster, D. A., Meert, J. G., Goscombe, B. D., Armstrong, R., Trouw, R. A. J., & Passchier, C. W. (2008). A Damara orogen perspective on the assembly of southwestern Gondwana. Geological Society, London, Special Publications, 294(1), 257–278.

• Korn, H., & Martin, H. (1959). GRAVITY TECTONICS IN THE NAUKLUFT MOUNTAINS OF SOUTH WEST AFRICA. Geological Society of America Bulletin, 70(8), 1047.

• Miller, R. McG., Frimmel, H. E., & Will, T. M. (2009). Chapter 5.8 Geodynamic Synthesis of the Damara Orogen Sensu Lato. In C. Gaucher, A. N. Sial, H. E. Frimmel, & G. P. Halverson (Eds.), Developments in Precambrian Geology (Vol. 16, pp. 231–235).

• Morris, D., Sanders, C. B., Grotzinger, J. P., Busch, J., Cury, L. F., Daoust, P., Fischer, W. W., Howes, B., Jones, D. S., Sheppard, R., Nelson, L. L., Pu, J. P., Quinn, D. P., Wilcots, J., & Swart, R.

• (2018). Cap Sequence Post-dating Marinoan Glacial Deposits, Naukluft Mountains, Namibia. 2018, PP53E-1238.

• Morris, F. K., & Grotzinger, J. P. (2023). Facies and stratigraphy of the basal Ediacaran cap carbonate, Naukluft Mountains, Namibia. Precambrian Research, 394, 107113.