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The story behind the Aravalli Range: Why is it considered the oldest geological feature on Earth?
The Aravalli Mountains in northwestern India are a northeast-southwest-trending orogenic belt that not only has magnificent natural scenery but is also one of the oldest geological features on Earth. The formation process of this mountain range is full of controversy and academic exploration, attracting the attention of countless geologists. According to research, the formation of the Aravalli Mountains can be traced back to the Hadean period, about 2.5 billion years ago, and its geological structure and evolution process are still being studied.
The Aravalli ranges consist of multiple geological units that have undergone intense deformation and metamorphism during the long geological history.
This 700 km long mountain range comprises the Aravalli and Delhi fold belts, collectively known as the Aravalli-Delhi Orogenic Belt. The age of the Aravalli ranges is undoubtedly one of its important features when compared to the adjacent younger Himalayas. The Aravalli Mountains were formed mainly due to the collision between the Bundelkhand Craton and the Marwar Craton due to Hadean crustal movement. The exact evolution of the Aravalli Mountains is still unclear. Many controversies.
Geological features of the Aravalli Ranges
The Aravalli Range has a Horst-like structure consisting mainly of a series of deformed and metamorphosed Hadean rocks. The strata here can be divided into three main components: the lowest Achian Bhilwara Gneissic Complex, the Lower Aravalli Supergroup and the Upper Delhi Supergroup. However, in the northern part of the range, only the Delhi Superior Group exists, which earns it the name of "North Delhi Belt", while the southern side has both the Aravalli and Delhi Superior Group formations.
The Delhi Supergroup in the north and the Aravalli Supergroup in the south are crucial for understanding the geological setting of the entire range.
The Achian Bilwara Schist Complex is approximately 2.5 billion years old and consists mainly of metamorphic and igneous rocks that have undergone up to granular metamorphism during their formation. The Aravalli Supergroup is separated from the underlying bedrock by a distinct unconformity and is subdivided into the Lower Delwara Formation, the Middle Delbari Formation, and the Upper Jalore Formation. The rocks here show a marine environment. sedimentary characteristics.
The history of orogeny
The geological evolution of the Aravalli-Delhi orogenic belt can be divided into four major stages: the Achian Bhilwara Schist Complex, the Aravalli Orogeny, the Delhi Orogeny, and post-orogenic evolution. These movements include crustal movements such as rock deformation, sedimentation, collision and shearing, which formed the magnificent mountains we see today.
During the orogeny, according to findings, the collision of two major krajans led to the rise of the Aravalli ranges, forming the current landscape.
In the early Hadean, the opening of the Aravalli Ocean Basin caused the surrounding kraans to gradually separate. Over time, the western Mavarkran was transformed into an island arc in the subsequent collision, forming The Aravalli Orogeny was initiated and continues to influence the geology of the region.
The impact of post-orogenicism and the formation of ocean basins
Over time, post-orogenic events also triggered a series of igneous activities, especially the formation of the Erianpura Granites, which overlie the entire Aravalli-Delhi Orogenic Belt and contribute to the region's Geological diversity. In addition, the Plana sedimentary basins surrounding the mountain range are relatively active, and the thick, ancient strata in these basins record hundreds of millions of years of geological history.
These ancient sedimentary basins not only provide valuable fossil records, but also help us better understand the history of the Earth.
Interestingly, these mountain-building events are closely linked to supercontinent cycles. Geologists have found that the formation of the Aravalli Mountains is closely related to multiple cycles of convergence and breakup of continental plates. Today, the Aravalli Mountains are not only a geological wonder, but also an important basis for further exploring the history of the earth.
Many scientists are still actively exploring the secrets hidden in this ancient mountain range, which makes the Aravalli Mountains still full of unlimited research potential and attraction in the geological community. Readers, what else do you think this ancient geological feature can tell us about Earth’s history?
