Marwar Supergroup Research Articles

Shallow crustal imaging beneath NW Indian terrane from teleseismic P-wave coda using a Bayesian approach

Deciphering the crustal architecture of the Cretaceous Barmer-Sanchore Basin (BSB) and Neoproterozoic provinces in the NW Indian Shield presents significant challenges due to extensive sediment deposition and widespread felsic igneous rocks. To address such intricacies, we employ a transdimensional Bayesian joint inversion of teleseismic P-wave polarizations and receiver functions to resolve the detailed structure of the upper 10 km of the crust beneath 29 seismic stations deployed in the study area. The new data is analyzed separately within each of the three different backazimuthal groups to identify any strong variations in the shallow subsurface structure and derive a more robust, averaged model for every station site. The resulting 1-D models reveal heterogeneous sediment cover in BSB and Marwar Basin, with respective thicknesses ranging from ∼1.3–5.5 km and 1–1.5 km. Remarkably low shear-wave velocities (Vs < 1.0 km/s) of sediments with increased Vp/Vs (>2.3) are observed in BSB and adjacent areas, which are related to highly unconsolidated Quaternary-Tertiary deposits. The Marwar Basin is imaged to have 0.3–0.5 km of uncompacted sediments that overlie 0.5–1 km thick Marwar Supergroup sequence. The Erinpura Granites (EG) and Malani Igneous Province (MIP) are characterized by a variably thick sediment blanket, typically ranging within 1 km in thickness. The Vs of the sediments in these regions exceeds 2.4 km/s that possibly corresponds to Mesozoic and older sediments. The basement beneath EG exhibits Vs faster than 3.4 km/s, consistent with moderately metamorphosed granites. In MIP, the basement is characterized by non-uniform shear velocities, suggesting the influence of intrusions linked to magmatic episodes in NW India.

Flabellophyton: The Benthic Macroalgal Fossils in Marwar Supergroup, India

ABSTRACT Here we report numerous fossil forms of the Ediacaran Flabellophyton genus in the Sonia Sandstone of the Jodhpur Group, Marwar Supergroup, in India. They are assigned as Flabellophyton lantianense, Flabellophyton stupendum, and Flabellophyton typicum species and have been found to have both positive and negative reliefs on the bedding planes of medium- to fine-grained sandstone in the Sursagar region of Jodhpur district. The thallus of Flabellophyton lantianensis occurs in straight to slightly curved and slender forms, is closely packed, and may have thin filaments. The Flabellophyton stupendum is a conical or fan-shaped thallus containing thin bundled filaments and has a discoidal holdfast with a well-differentiated stipe. The Flabellophyton typicum species typically has a thallus with an intermediate conical shape, a globular holdfast with an acute stipe, and a fan-shaped form with bundles of thin filaments. These studied Flabellophyton fossil assemblages are well comparable to those found in South China and South Australia in their conical or fan-shaped morphologies and holdfast structures (mostly found in F. stupendum and F. typicum species) with fine and thin bundled filaments. In accordance with this study, these Flabellophyton fossil assemblages are probably benthic macroalgal fossils. Here, the fossil assemblages of Flabellophyton from India are described for the first time.

Marinoan glaciation in the Indian subcontinent - Anatomy and global implications

Detailed sedimentological analysis of the Pokaran Boulder Bed, representing the most basal unit of the Neoproterozoic-Lower Cambrian Marwar Supergroup, clearly indicates its glacial origin. The glacial sediments are interpreted as an ice-contact submarine fan deposit. Based on the detrital and inherited zircon population of the Marwar Supergroup sediments and interlayered pyroclastic deposits, a Marinoan cryochron of the Cryogenian Period is envisaged for the Pokaran Boulder Bed. The well-preserved Ediacaran elements in the post-glacial sedimentary succession also support a Cryogenian to Early Cambrian age of the Marwar Supergroup. The glacial deposition at the base of the Marwar Supergroup strengthens the regional correlation between the studied sediments with the Lesser Himalayan Blaini-Krol-Tal sediments and the Haqf Supergroup of Oman. The available zircon ages and paleomagnetic data of the Malani Igneous suite, along with the Marinoan glacial deposits, detrital zircon ages, and Ediacaran fossil elements of the Marwar Supergroup add significant information to the Neoproterozoic Earth history.

The anchor-shaped Ediacaran organism Parvancorina from Marwar Supergroup, India

The anchor-shaped Ediacaran organism Parvancorina from Marwar Supergroup, India

Assessment and Threat to Significant Geoheritage of Soorsagar Formation of Jodhpur Group of Marwar Supergroup, Western Rajasthan, India: A Geological and Remote Sensing Approach

Assessment and Threat to Significant Geoheritage of Soorsagar Formation of Jodhpur Group of Marwar Supergroup, Western Rajasthan, India: A Geological and Remote Sensing Approach

Tracing source and palaeo‐weathering conditions of quartzose sandstone in the Cretaceous Cambay Basin: A combined petrographical, geochemical and geochronological approach

Based on detrital monazite dating, mineral chemistry of tourmaline and rutile, bulk rock geochemistry, modal analysis of petrographic and palaeocurrent data, this study tracks the source of quartzose sandstone within the Cretaceous succession of the Cambay Basin primarily to rocks within the Aravalli‐Delhi Fold Belt. Monazite geochronology shows predominant peaks around 506 ± 11 Ma, 905 ± 12 Ma and a minor peak at 750 ± 20 Ma, 1485 ± 30 Ma relating sediment sources to the Aravalli‐Delhi orogeny and Pan‐African orogeny. The petrographic modal analysis of the moderate‐to‐well‐sorted Himmatnagar Sandstone indicates at least 91% quartz, with minor feldspar and rock fragments. The mineral chemistry of tourmalines in Himmatnagar Sandstone matches with Li‐ and Ca‐poor granitoid, pegmatites, metapelites and quartz tourmaline rocks. The trace element content of rutiles in sandstones corresponds to metapelitic sources. Detrital monazite dates and mineral chemistry of tourmalines and rutiles pinpoint the sediment source to the South Delhi Supergroup of rocks. The dominance of rounded zircons and tourmalines and abraded quartz overgrowth in the Himmatnagar Sandstone indicate the recycling of sediments, possibly from the Marwar Supergroup. Palaeoclimatic proxies based on mineralogy and geochemistry, particularly, the high value (93–97) of mineralogical index alteration, indicate intense chemical weathering of the source rocks under humid climatic conditions. Therefore, the combination of factors, including the quartzo‐feldspathic source rocks, intense chemical weathering under humid climatic conditions and the recycling of sediments facilitated the formation of quartzose sandstone within the Himmatngar Sandstone in the Cambay Basin.

Pb-Pb age of the Gotan Limestone, Marwar Supergroup: Implications for Ediacaran-Cambrian transition events in the peninsular India

The rocks of the Marwar Supergroup of western India are known to contain important clues for the evolution of complex multicellular life, changes in chemistry of ocean water, and changes in global climate during the Proterozoic-Cambrian transition. However, the timings of these event markers remain tentative due to insufficient radiometric ages. Here, we present dating results of the only limestone formation of the supergroup, the Gotan Limestone of the Bilara Group, by Pb-Pb method and use the existing chemo/chrono stratigraphic information to provide constraints on the age of deposition of the supergroup. The 207Pb/204Pb-206Pb/204Pb isochron yielded an age of 537 ± 19 (2σ) Ma, which is in agreement with the age estimate suggested by 87Sr/86Sr stratigraphy. Therefore, the negative excursions observed in the δ13C record of the Bilara Group should now be assigned terminal Ediacaran and early Cambrian ages, respectively. This new Pb-Pb age considered together with δ13C and 87Sr/86Sr stratigraphic records suggests that the Ediacaran-Cambrian transition in the Marwar Supergroup is likely contained within the Bilara Group, and it is the first such report from the peninsular India.

Prodigious shift in provenance across Permian-Triassic Boundary at Guryul Ravine Section, Kashmir, Tethys Himalaya, India: Evidences from Sr and Nd isotopes

The Permian-Triassic Boundary (PTB) section (Late Permian Zewan Formation and Early Triassic Khunamuh Formation) at Guryul Ravine (Kashmir, India) preserves potentially important information about the depositional conditions and provenance changes across the PTB. Several palaeobiological, sedimentological and geochemical studies have been conducted on this archetypal section to understand the causes of mass extinction at the PTB, however no integrated chemo-stratigraphic study focusing on provenance and geodynamics has been attempted. In the present study, samples from a 36 m thick interval across the PTB are analysed for major and trace element concentrations, Sr-, Nd- and Corg isotope geochemistry along with TOC (total organic carbon) contents to understand the contemporary environmental and provenance changes. The Late Permian Zewan Formation have relatively low chemical index of alteration (CIA) values (55–77) and low αAlCa (0.1–12.6), αAlNa (0.7–9.6), αAlMg (1.0–6.1) values, implying moderate weathering conditions; whereas the Early Triassic sediments of overlying Khunamuh Formation show higher CIA (69–79) and αAlCa (1.4–14.0), αAlNa (2.2–11.5), αAlMg (2.0–6.4) values indicating more intense chemical weathering conditions. The vertical profiles of δ13Corg, δ34Spyr and various redox-indicators suggest euxinic-anoxic condition during the latest Permian, and show a significant change in depositional conditions from anoxic to oxic across the PTB. The significant finding of the present study is the dramatic change of Sr- and Nd isotopic compositions across the PTB, indicating remarkable shift in provenance. The Late Permian samples show much less-radiogenic ɛNd(0) (avg. –15.27), radiogenic 87Sr/S6Sr(0) (avg. 0.72409) and older TDM ages (1.35–1.56 Ga) compared to the early Triassic samples (avg. εNd(0) = −9.49,87Sr/S6Sr(0) = 0.719282, TDM = 1.71–1.76 Ga). The εNd(0) and 87Sr/S6Sr(0) composition of Late Permian rocks overlap with the signatures of Tethyan Himalaya and Neoproterozoic-Cambrian Marwar Supergroup of NW India, indicating similar old cratonic sources. Higher εNd(0), younger TDM ages and lower 87Sr/86Sr(0) in Triassic samples suggest contribution from juvenile sources and Panjal volcanics, Cadimian arc of Cimmeria or African-Nubian shield could be the likely source terrains.

U-Pb zircon geochronology of volcaniclastics and encasing sandstones from the Chhoti Khatu section: Bearing on the Neoproterozoic Marwar Supergroup stratigraphy and its global implications

• Detrital zircon geochronology from volcaniclastic, sandstones of Khatu section. • An epiclastic origin is suggested for the volcaniclastic, instead of volcanic ash. • A ∼1000 Ma crystallization age for the igneous body that supplied the epiclastics. • From 870 Ma youngest zircon a pre-Jodhpur deposition suggested for Khatu section. • Multitude of provenances including South China Craton in ‘Gondwana’ assembly. An isolated ∼40 m thick outcrop section, namely the Chhoti Khatu section, containing an embedded volcaniclastic layer, in the southeast of the Marwar Basin, western India (erstwhile stratigraphically correlated with the Jodhpur Group of the Marwar Supergroup) has drawn attention from geoscientists in recent time for fixation of geochronologic age and time bracketing of the basin succession. A detail petrography of suggestive volcaniclastic unit reveals dominance of detrital sedimentary clasts over volcaniclastic fragments. An admixture of silt and sand-sized highly angular clasts of quartz, feldspar, volcanic crystal, and lithic fragment; delicate-shaped glass/pumice shards and mica grains in fragmentary texture either in grain-supported mode or as floating clasts within glassy, microlitic matrix represent the volcaniclastic layer present at the Khatu section. An epiclastic origin is inferred for the unit, instead of a felsic tuff, as inferred earlier. A comparison between U-Pb zircon age data from the epiclastic unit and its encasing sandstones allowed interpretation of a ∼1000 Ma crystallization age for the igneous body from where volcanic clasts were derived in the Khatu epliclastics. The youngest zircon peak of ∼870 Ma at the Khatu section indicates the maximum depositional age for Khatu sedimentation. A comparison between Khatu detrital zircon geochronology data and published zircon geochronology data from the Jodhpur Group of the Marwar Supergroup allowed us to infer a pre-Jodhpur depositional history for the Chhoti Khatu section. This raises a need to reappraise the earlier proposed stratigraphic correlation between the Khatu succession and the Jodhpur Group of rocks form the Marwar Basin.

Phenomenal Preservations of Stromatolites in Bilara Group of Marwar Supergroup, Western India: Implication for Establishment as Geosites

Phenomenal Preservations of Stromatolites in Bilara Group of Marwar Supergroup, Western India: Implication for Establishment as Geosites

Epithermal Vanadium Mineralization in Sonia Sandstone of Marwar Supergroup, India

Abstract Present study of vanadium mineralization in the Sonia sandstone of Jodhpur Group shows first hydrothermal activity in the Sonia sandstone of Marwar Supergroup. The Sonia sandstone served as a host for the mineralizing solutions. The vanadium mineralization occurred in sandstone- gritty sandstone-conglomerate along faults. Field relationship and petrological study suggests that mineralization is filled by epithermal solutions and provide a better understanding of the timing and nature of the alteration processes. Though the source of the vanadium is not well constrained, but is possibly from the partial melting of banded gneissic complex-II (Sirohi Group), the source (crustal) melt had assimilated material from the rocks of Sirohi Group in significant amount. Deposition of tuffs at top of Sonia Formation (Chhoti Khatu) and emplacement of last stage Malani dykes suggest that the last phase of Malani magmatism generated heat for the partial melting of banded gneissic complex-II (Sirohi Group). The occurrence of vanadium in sandstone–gritty sandstone–conglomerate from Sonia Formation of Marwar Supergroup has opened a new chapter to explore uranium which generally occurs after vanadium mineralization in conglomeratic sedimentation.

Tonian and Cryogenian – Early Cambrian sedimentation in NW India: Implications on the transition from Rodinia to Gondwana

The Tonian Punagarh-Sindreth and Cryogenian – early Cambrian Marwar sequences in NW India encompass a geological record that could provide vital information for working out the tectonic evolution of this region and a better understanding of the Rodinia to Gondwana transition. The Tonian Punagarh and Sindreth sub-basins received a dominantly felsic detritus with negligible sorting of heavy minerals and mild to weak chemical weathering conditions. The clastic compositions and geochemical characteristics of the Punagarh and Sindreth groups suggest a back-arc basin setting and the detritus sourced from a volcanic arc and cratonic interior region. The Punagarh basin was proximal to the craton while the Sindreth basin was close to an arc system. In contrast, the Cryogenian – early Cambrian Marwar Supergroup clastic sequence contains mature quartz arenite whose high CIA (77.8–94.8) and low ICV (0.18–1.00) values suggest a strong chemical weathering in the source region and noteworthy physical sorting during transportation and sedimentation. An abundance of quartz grains (87–94%), enrichment of Zr, and detritus predominantly derived from the cratonic basement indicate deposition of Marwar sediments in a tectonically stable basin, temporally coinciding with the Gondwana assembly. Collectively, the ∼ 760 Ma active continental margin in NW India, documented by the provenance and tectonic setting of the Punagarh and Sindreth basins, is in agreement with the subduction of the peripherical Rodinia supercontinent during its breakup. On the other hand, the passive continental margin sedimentation in Marwar Supergroup points toward an open sea between NW India and western Gondwana during the Gondwana assembly.

The early Cambrian (Series 2, Stage 3) burrows from the Nagaur Sandstone, Marwar Supergroup, Rajasthan, India: palaeoenvironmental and palaeoecological considerations

The early Cambrian (Series 2, Stage 3) burrows from the Nagaur Sandstone, Marwar Supergroup, Rajasthan, India: palaeoenvironmental and palaeoecological considerations

Hiemalora stellaris from Ediacaran Sonia Sandstone of Jodhpur Group of Marwar Supergroup, Western Rajasthan, India

Abstract The present study reports and discusses discoidal Ediacaran body fossils identified as Hiemalora stellaris from the Sonia Sandstone of Jodhpur Group, Marwar Supergroup, Western Rajasthan, India. These are preserved as positive relief on the yellowish-brown to pinkish-brown medium to fine-grained sandstone bedding surfaces in Sursagar area. Morphologically, these are circular to sub-circular, mostly flat-discoidal forms or discs surrounded by numerous radiating arms or appendages resembling tentacles. Hiemalora is reinterpreted and reconstructed as discoidal hold fast of benthic organism but not found the attached fronds or stem-like structures of the hold fasts in the present materials. The systematic palaeontology, palaeobiology, palaeoenvironment and age of the Hiemalora bearing Ediacaran Sonia Sandstone have been also discussed.

C-Sr isotope stratigraphy of carbonate formations of the late Neoproterozoic - Cambrian Marwar Supergroup, western India

The Ediacaran-Cambrian transition period was one of the most significant intervals in the Earth’s history. Widespread changes in the oceanic and atmospheric conditions characterized this interval, which likely triggered the radiation of metazoans. Much of our knowledge of these changes have come from geochemical studies of marine carbonates deposited during this time. In search of such information and to establish the true geographical extent of these events, we carried out a detailed field and geochemical investigation in the Bilara Group of the Marwar Supergroup, the youngest Proterozoic marine carbonate succession of peninsular India. The variations in the 87Sr/86Sr observed in the limestone formation of the Bilara Group (0.70810 to 0.70916) suggest an early Cambrian (520–539 Ma) depositional age for the Group. We identify two δ13C negative excursions of magnitudes ~6‰ and ~7‰, respectively, in the middle and lower parts of the Bilara Group. Since these δ13C anomalies are observed through-out the Marwar Basin that was connected to global oceans, we believe that they represent temporal changes in the chemistry of seawater. Using the principles of δ13C stratigraphy and the available geochronological information, we correlate the middle Bilara anomaly to the Shiyantou carbon isotope excursion (SHICE). Although, poor age constraints hinder a definitive correlation of the older Bilara anomaly, we speculate that it is the basal Cambrian carbon isotope excursion (BACE). These results place the Ediacaran-Cambrian boundary closer to the basal part of the Bilara Group in the Marwar Supergroup.

Age of the Marwar Supergroup, NW India: A note on the U–Pb geochronology of Jodhpur Group felsic volcanics

The Marwar Supergroup (NW Peninsular India) is thought to be of Ediacaran-Cambrian age, based on previous paleontological and geochronological studies. However, direct constraints on the onset of sedimentation within the Marwar basin are still scarce. In this study, we report U–Pb zircon, LA-ICP-MS, and SIMS ages from the Chhoti Khatu felsic volcanic rocks, interlayered with the Jodhpur Group sandstones (Lower Marwar Supergroup). The cathodoluminescence images of the zircons indicate complex morphologies, and core-rim textures coupled with the wide range of ages indicate that they are likely inherited or in the case of thin poorly indurated ash-beds, detrital in origin. The age spectra of 68 zircon analyses from our sampling display a dominant 800–900 Ma age peak corresponding to the age of basement “Erinpura granite” rocks in the region. The youngest inherited zircon from a felsic ash layer yielded a U–Pb age of 651 Ma ± 18 Ma that, together with previous studies and paleontological evidence, indicates a post-Cryogenian age for the initiation of Marwar sedimentation following a ~125 Ma hiatus between the end of Malani magmatism and Marwar deposition.

Identification of lanostanes, A-ring methylated steranes and secosteranes in late Neoproterozoic crude oils by GC×GC-TOFMS: New insights into molecular taphonomy of steroids

The late Neoproterozoic marine succession (Marwar Supergroup) deposited in the Bikaner-Nagaur Basin in western India is an excellent provenance to study steroid biomarkers. Traditional one-dimensional gas chromatography mass spectrometry (GC–MS) and metastable reaction monitoring (MRM) transitions have been previously employed for routine biomarker analyses of crude oils and sediments. The present study with GC×GC-TOFMS (time-of-flight mass spectrometer) demonstrates an improved distribution of the sterane compounds segregated from the co-eluting n-alkanes, cycloalkanes and triterpanes in terminal Proterozoic crude oils. The steranes identified here offer novel insights into the molecular taphonomic alteration of eukaryotic lipids during the late Neoproterozoic. The presence of lanostane and 3β alkyl steranes is probably indicative of a depositional environment stressed by high salinity. To the best of our knowledge, this is the oldest known record of lanostane steroids found in the geosphere. Secosteranes with an open C-ring form as a result of diagenetic cleaving of carbon–carbon bonds. The concomitant presence of 2α-, 3β - and 4α-methyl steranes (A-ring methylated steranes) reflects specific biological input and a distinct palaeo-depositonal environment. The 3β - and 2α-methyl steranes probably form by migration of methyl substituents within the steroid structure. The recognition of a diverse range of steroid compounds by GC×GC-TOFMS advocates its excellent analytical potential in the study of natural products in geological samples. Hence, this state-of-the-art technology will be worth using for re-evaluating and investigating hydrocarbon biomarkers in order to minimize the gaps that exist in the understanding of biotic evolution over geological time scales.

Authigenic δ13C-carb Negative Excursion in the Late Ediacaran-Early Cambrian Bilara Group, Marwar Supergroup, India

Abstract Late Ediacaran-early Cambrian sedimentary rocks from different palaeogeographical locations have recorded heterogeneous extreme negative carbon isotope excursions, which is commonly interpreted as a major event in the concurrent global carbon cycling. To understand the inorganic and organic carbon sourcing and type of the depositional environment that led to the negative δ13C-carb excursion, this study has re-assessed the high resolution inorganic and organic isotopes (δ13C-carb, δ18O-carb, and δ13C-org) and total organic carbon (TOC) data from the late Ediacaran-early Cambrian carbonate section of the Bilara Group, Marwar Supergroup, India. Statistical correlation analysis among δ13C-carb, δ18O-carb, δ13C-org and TOC data suggest that the Bilara carbonates were mainly deposited in a closed/semiclosed oligotrophic palaeobasin that was intermittently connected to the open ocean during eustatic sea-level rise. Steered by the water-level/volume fluctuations in the Bilara palaeobasin, the epicenter of carbonate precipitation shifted between the surface water column and sediment-water interface/sedimentary column. The negative δ13C-carb excursion was a result of increased authigenic carbonate precipitation, fuelled by anaerobic oxidation of organic matter at the sediment-water interface/ in the sedimentary column during the high water-level/volume in the Bilara palaeobasin.

On Chhoti Khatu volcanics of Rajasthan and its relationship with the Malani magmatism: A geochemical study

Malani Igneous Suite represents the largest felsic volcanic province in India. Despite a number of studies, the origin and the temporal extent of the Malani magmatism remain elusive. Adjacent to the Malani Igneous Suite, there exists a calcareous felsic tuff deposit at Chhoti Khatu within the younger Marwar Supergroup. It is stratigraphically separated from the Malani Igneous Suite by the Sonia Formation, the bottom-most formation of the supergroup, but falls within the temporal range of the Malani magmatism. In order to explore its genetic relationship with the Malani Igneous Suite and decipher its origin, trace element and C–O–Sr–Nd isotopic compositions of the tuff were studied. The results of the study show that the tuff differs geochemically from the MIS, and therefore, could not have been an extension of the Malani magmatism as believed by many earlier workers. On the basis of trace element patterns and Sr–Nd isotopic data, origin of the tuff is ascertained to the partial melting of Banded Gneissic Complex-II, the Archean–Paleoproterozoic basement of the region. The C and O isotopic composition of the carbonates from the tuff and a two-component mixing model reveal that the source (crustal) melt for the tuff had assimilated a significant amount of material from the rocks of the Sirohi Group. Since the timing of deposition of the tuff coincide with the emplacement of late-stage Malani dykes, it is likely that the final phase of Malani magmatism generated the heat for partial melting of the Archean–Paleoproterozoic basement.

Tracing multiple sources of sediments using trace element and Nd isotope geochemistry: provenance of the Mesozoic succession in the Kutch Basin, western India

AbstractAn integrated approach involving Sr–Nd isotope, trace and rare earth element analyses tracks multiple sources of the Mesozoic sediments of the Kutch Basin at the western continental margin of India. High (87Sr/86Sr)t (ratio at time of deposition), negative εNd and high concentrations of large-ion lithophile elements (LILEs) indicate the upper continental source. Ratios of Nb/Ta and Zr/Hf suggest sedimentary and felsic igneous sources of sediments. The moderate to high concentration of La, Th and Sc, light rare earth elements (LREE-) enrichment, weak negative Eu anomalies and the relationship between εNd(0) and Th/Sc indicate the dominantly felsic composition of source rocks. However, low contents of Th, low values of (87Sr/86Sr)t and depleted mantle model age TDM &lt; 1600 Ma indicate input from a younger mafic source. Increasing concentrations of Zr, Hf and Nd isotopes and a gradual increase in mean TDM from the older to the younger formations indicate erosional unroofing at the source terrain. The increasing (87Sr/86Sr)t through time relates to increased weathering of the source rock. The overwhelmingly southwesterly palaeocurrent direction of current-generated sedimentary structures, and the mean TDM ages trace suggest source areas of the Kutch Basin to Precambrian rocks in the north and NE of this basin. The TDM ages highlight the dominance of late Palaeoproterozoic source rocks. Nd isotope composition indicates that Proterozoic rocks of Marwar Supergroup and Erinpura Granite, in particular, served as main sediment contributors for the Mesozoic sediments in Kutch. We therefore conclude that the Mesozoic sediments in the Kutch Basin are predominantly of late Palaeoproterozoic age with lesser inputs from rocks of early Mesoproterozoic and early Palaeoproterozoic age.