Researchers have determined that prolonged periods of drought intensify tectonic activity within the East African Rift Zone. A study of sediment cores from the region’s major lakes, published in the journal Scientific Reports, revealed that water level decreases over the last five millennia have spurred tectonic processes that could eventually cause the separation of East Africa.
Professor Christopher Scholz from Columbia University pointed out that climatic shifts not only follow tectonic movements but also exert an influence upon them. The research focused on Lake Turkana in Kenya, a body of water stretching 250 kilometers with a maximum depth reaching 120 meters. During a wetter era, approximately five thousand years ago, the lake’s water level stood 30 meters higher.
The African Humid Period spanned from 9,600 to 5,300 years ago, after which the climate transitioned to a drier state. Analysis of lakebed sediments and evidence of ancient earthquakes demonstrated that the drop in water levels amplified the tectonic forces along the rift faults.
The eastern portion of the African lithospheric plate is gradually diverging, a process that conceivably could lead to the creation of a new oceanic basin. Deep lakes in the area, such as Turkana and Malawi, owe their existence to these tectonic motions. Scholz commented that the reduction in hydrostatic pressure expedites the movement of the Earth’s crust. Furthermore, an active volcano with a magma chamber resides beneath Lake Turkana, and lower water levels facilitate an increase in its activity and a strengthening of tectonic processes.
The scientists calculated that the rate of fault displacement has increased by approximately 0.17 mm per year. The overall rate of lithospheric plate separation is around 6.35 mm annually. The investigators concluded that current tectonic activity exceeds the levels witnessed eight thousand years prior.
Future stages involve investigating how climatic variations have affected geological processes in Lake Malawi over the preceding 1.4 million years.
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