Western RajasthanWestern Rajasthan, located in northwestern India, represents a pivotal component of the Indian Shield, preserving an extensive geological record that extends from the Archaean era to contemporary times. The area’s supracrustal formations encompass the Banded Gneissic Complex (BGC), along with the Aravalli, Delhi, and Vindhyan Supergroups, covering a temporal span of approximately 3500–800 million years ago (Ma), delineated by significant regional unconformities. During the late Proterozoic, the region experienced the voluminous Malani Igneous Suite, a prominent felsic volcanic episode featuring rhyolites, tuffs, and granitic intrusions across an expanse of roughly 55,000 km2. Overlying this suite is the Marwar Supergroup (Neoproterozoic to Cambrian), composed of sandstones, limestones, and evaporites, with ichnofossils suggesting a Lower Cambrian affinity. Paleozoic deposits are sparse, highlighted by the Carboniferous Bap Boulder Bed and Permian Badhaura Formation, which document limited glacial and marine sedimentation. Mesozoic strata, predominantly Jurassic, include the Lathi and Jaisalmer Formations, exhibiting fluvial and marine deposits enriched with fossilized wood and trace fossils. Tertiary sequences in the Jaisalmer, Barmer, and Palana-Ganganagar basins illustrate transitions from marine to continental environments, represented by formations such as Sanu, Khuiala, and Bandha. The Quaternary deposits of the Thar DesertThar desert, influenced by Neogene tectonic activities, comprise fluvial, fluvio-lacustrine, and aeolian sediments, alongside calcretes and soils reflective of persistent arid conditions. This multifaceted geological tapestry, shaped by multiple orogenic cycles, tectonic upheavals, and climatic fluctuations, highlights the critical role of western RajasthanWestern Rajasthan in elucidating India’s geodynamic history. Recent investigations, including paleomagnetic analyses and geochemical studies have refined the timing and petrogenetic models of the Malani Igneous Suite, linking it more robustly to global Neoproterozoic tectonic events such as Rodinia’s fragmentation. Furthermore, contemporary climate studies reveal ongoing greening trends in the Thar DesertThar desert due to enhanced monsoon precipitation and anthropogenic groundwater extraction, increasing vegetation coverVegetation cover by up to 38% since 2000. These developments underscore the interplay between ancient geology and modern environmental dynamics, with implications for sustainable resource management in arid zonesArid zone.

An Overview of the Geology of Western Rajasthan, India

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发表日期：

2026年

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Arun Vyas,
Mahesh K. Gaur,
Komal Vyas

摘要

Western RajasthanWestern Rajasthan, located in northwestern India, represents a pivotal component of the Indian Shield, preserving an extensive geological record that extends from the Archaean era to contemporary times. The area’s supracrustal formations encompass the Banded Gneissic Complex (BGC), along with the Aravalli, Delhi, and Vindhyan Supergroups, covering a temporal span of approximately 3500–800 million years ago (Ma), delineated by significant regional unconformities. During the late Proterozoic, the region experienced the voluminous Malani Igneous Suite, a prominent felsic volcanic episode featuring rhyolites, tuffs, and granitic intrusions across an expanse of roughly 55,000 km2. Overlying this suite is the Marwar Supergroup (Neoproterozoic to Cambrian), composed of sandstones, limestones, and evaporites, with ichnofossils suggesting a Lower Cambrian affinity. Paleozoic deposits are sparse, highlighted by the Carboniferous Bap Boulder Bed and Permian Badhaura Formation, which document limited glacial and marine sedimentation. Mesozoic strata, predominantly Jurassic, include the Lathi and Jaisalmer Formations, exhibiting fluvial and marine deposits enriched with fossilized wood and trace fossils. Tertiary sequences in the Jaisalmer, Barmer, and Palana-Ganganagar basins illustrate transitions from marine to continental environments, represented by formations such as Sanu, Khuiala, and Bandha. The Quaternary deposits of the Thar DesertThar desert, influenced by Neogene tectonic activities, comprise fluvial, fluvio-lacustrine, and aeolian sediments, alongside calcretes and soils reflective of persistent arid conditions. This multifaceted geological tapestry, shaped by multiple orogenic cycles, tectonic upheavals, and climatic fluctuations, highlights the critical role of western RajasthanWestern Rajasthan in elucidating India’s geodynamic history. Recent investigations, including paleomagnetic analyses and geochemical studies have refined the timing and petrogenetic models of the Malani Igneous Suite, linking it more robustly to global Neoproterozoic tectonic events such as Rodinia’s fragmentation. Furthermore, contemporary climate studies reveal ongoing greening trends in the Thar DesertThar desert due to enhanced monsoon precipitation and anthropogenic groundwater extraction, increasing vegetation coverVegetation cover by up to 38% since 2000. These developments underscore the interplay between ancient geology and modern environmental dynamics, with implications for sustainable resource management in arid zonesArid zone.