Rift-associated ultramafic lamprophyre (damtjernite) from the middle part of the Lower Cretaceous (125 Ma) succession of Kutch, northwestern India: Tectonomagmatic implications
Mineralogical, geochemical and isotopic (Sr and Nd) studies on the recently reported ca. 124 Ma ‘anorogenic lamproite’ dyke from the Palanpur area, Kutch seismogenic rift zone, northwestern India, are presented. We propose a new classification for the dyke as a damtjernite (ultramafic lamprophyre; U...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2018-11-01
|
| Series: | Geoscience Frontiers |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S1674987117301949 |
| _version_ | 1797716180489732096 |
|---|---|
| author | Rohit Pandey N.V. Chalapathi Rao Prashant Dhote Dinesh Pandit A.K. Choudhary Samarendra Sahoo B. Lehmann |
| author_facet | Rohit Pandey N.V. Chalapathi Rao Prashant Dhote Dinesh Pandit A.K. Choudhary Samarendra Sahoo B. Lehmann |
| author_sort | Rohit Pandey |
| collection | DOAJ |
| description | Mineralogical, geochemical and isotopic (Sr and Nd) studies on the recently reported ca. 124 Ma ‘anorogenic lamproite’ dyke from the Palanpur area, Kutch seismogenic rift zone, northwestern India, are presented. We propose a new classification for the dyke as a damtjernite (ultramafic lamprophyre; UML) based on its porphyritic-panidiomorphic texture, abundance of phlogopite, presence of nepheline in the groundmass, and the composition of liquidus phases such as olivine, phlogopite, magnetite, and clinopyroxene (diopside). The Palanpur UML is primitive (Mg# = 74–77), silica-undersaturated (SiO2 <40 wt.%), potassic to slightly sodic in nature, and is strikingly similar to the ∼69 Ma UML dykes and sills of the Tethyan Indus suture zone, which are considered as the earliest yet known manifestations of the Deccan Large Igneous Province (LIP). Bulk-rock (87Sr/86Sr)i (0.70460–0.70461) and ɛNd(t) (+2.56 to −0.69) of the Palanpur UML signify derivation from a slightly depleted mantle source similar to that of asthenospheric magmas such as OIB. This is further attested to by the high incompatible trace element ratios (viz., La/Ba, Nb/U, Nb/La and Ta/Yb) that are typical of plume-type magmas. However, the Neoproterozoic TDM depleted mantle Nd model ages (∼655–919 Ma) also necessitate some involvement of a lithospheric mantle component in its genesis. High bulk-rock Fe2O3t and TiO2 contents require the involvement of a fertile peridotitic mantle source, whereas high La/Yb (60–80) implies a control by residual garnet. Higher Rb/Sr and lower Ba/Rb suggest phlogopite as a residual phase and high Nb and lower La/Sm favour carbonatite, rather than silicate melt as metasomatising agent. Low degrees of partial melting of a primitive garnet lherzolite mantle can account for the observed REE patterns in the Palanpur UML. The Palanpur UML shares a temporal similarity to the Kerguelen plume-derived Rajmahal basalts and associated alkaline rocks from the eastern India. The tectonomagmatic significance of its emplacement during the mid-Cretaceous vis-à-vis various models involving the timing of eruption of the Deccan and the Rahmahal Traps and the rifting in the Kutch basin induced by far-field plate reorganization is evaluated. Keywords: Tectonomagmatism, Cretaceous, Ultramafic lamprophyre, Rift, Kutch, India |
| first_indexed | 2024-03-12T08:17:45Z |
| format | Article |
| id | doaj.art-51a7806fc3b34f6394e61688c26a36f8 |
| institution | Directory Open Access Journal |
| issn | 1674-9871 |
| language | English |
| last_indexed | 2024-03-12T08:17:45Z |
| publishDate | 2018-11-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Geoscience Frontiers |
| spelling | doaj.art-51a7806fc3b34f6394e61688c26a36f82023-09-02T18:44:36ZengElsevierGeoscience Frontiers1674-98712018-11-019618831902Rift-associated ultramafic lamprophyre (damtjernite) from the middle part of the Lower Cretaceous (125 Ma) succession of Kutch, northwestern India: Tectonomagmatic implicationsRohit Pandey0N.V. Chalapathi Rao1Prashant Dhote2Dinesh Pandit3A.K. Choudhary4Samarendra Sahoo5B. Lehmann6Electron Probe Micro Analyzer Laboratory, Department of Geology, Centre of Advanced Study, Banaras Hindu University, Varanasi 221005, IndiaElectron Probe Micro Analyzer Laboratory, Department of Geology, Centre of Advanced Study, Banaras Hindu University, Varanasi 221005, India; Corresponding author.Bhumi Geoservices, 1 & 2, Maa Bamleshwari Nagar, Godhani Railway, Nagpur 441111, MS, IndiaElectron Probe Micro Analyzer Laboratory, Department of Geology, Centre of Advanced Study, Banaras Hindu University, Varanasi 221005, IndiaInstitute Instrumentation Centre, Indian Institute of Technology, Roorkee 247667, IndiaElectron Probe Micro Analyzer Laboratory, Department of Geology, Centre of Advanced Study, Banaras Hindu University, Varanasi 221005, IndiaMineral Resources, Technical University of Clausthal, 38678 Clausthal-Zellerfeld, GermanyMineralogical, geochemical and isotopic (Sr and Nd) studies on the recently reported ca. 124 Ma ‘anorogenic lamproite’ dyke from the Palanpur area, Kutch seismogenic rift zone, northwestern India, are presented. We propose a new classification for the dyke as a damtjernite (ultramafic lamprophyre; UML) based on its porphyritic-panidiomorphic texture, abundance of phlogopite, presence of nepheline in the groundmass, and the composition of liquidus phases such as olivine, phlogopite, magnetite, and clinopyroxene (diopside). The Palanpur UML is primitive (Mg# = 74–77), silica-undersaturated (SiO2 <40 wt.%), potassic to slightly sodic in nature, and is strikingly similar to the ∼69 Ma UML dykes and sills of the Tethyan Indus suture zone, which are considered as the earliest yet known manifestations of the Deccan Large Igneous Province (LIP). Bulk-rock (87Sr/86Sr)i (0.70460–0.70461) and ɛNd(t) (+2.56 to −0.69) of the Palanpur UML signify derivation from a slightly depleted mantle source similar to that of asthenospheric magmas such as OIB. This is further attested to by the high incompatible trace element ratios (viz., La/Ba, Nb/U, Nb/La and Ta/Yb) that are typical of plume-type magmas. However, the Neoproterozoic TDM depleted mantle Nd model ages (∼655–919 Ma) also necessitate some involvement of a lithospheric mantle component in its genesis. High bulk-rock Fe2O3t and TiO2 contents require the involvement of a fertile peridotitic mantle source, whereas high La/Yb (60–80) implies a control by residual garnet. Higher Rb/Sr and lower Ba/Rb suggest phlogopite as a residual phase and high Nb and lower La/Sm favour carbonatite, rather than silicate melt as metasomatising agent. Low degrees of partial melting of a primitive garnet lherzolite mantle can account for the observed REE patterns in the Palanpur UML. The Palanpur UML shares a temporal similarity to the Kerguelen plume-derived Rajmahal basalts and associated alkaline rocks from the eastern India. The tectonomagmatic significance of its emplacement during the mid-Cretaceous vis-à-vis various models involving the timing of eruption of the Deccan and the Rahmahal Traps and the rifting in the Kutch basin induced by far-field plate reorganization is evaluated. Keywords: Tectonomagmatism, Cretaceous, Ultramafic lamprophyre, Rift, Kutch, Indiahttp://www.sciencedirect.com/science/article/pii/S1674987117301949 |
| spellingShingle | Rohit Pandey N.V. Chalapathi Rao Prashant Dhote Dinesh Pandit A.K. Choudhary Samarendra Sahoo B. Lehmann Rift-associated ultramafic lamprophyre (damtjernite) from the middle part of the Lower Cretaceous (125 Ma) succession of Kutch, northwestern India: Tectonomagmatic implications Geoscience Frontiers |
| title | Rift-associated ultramafic lamprophyre (damtjernite) from the middle part of the Lower Cretaceous (125 Ma) succession of Kutch, northwestern India: Tectonomagmatic implications |
| title_full | Rift-associated ultramafic lamprophyre (damtjernite) from the middle part of the Lower Cretaceous (125 Ma) succession of Kutch, northwestern India: Tectonomagmatic implications |
| title_fullStr | Rift-associated ultramafic lamprophyre (damtjernite) from the middle part of the Lower Cretaceous (125 Ma) succession of Kutch, northwestern India: Tectonomagmatic implications |
| title_full_unstemmed | Rift-associated ultramafic lamprophyre (damtjernite) from the middle part of the Lower Cretaceous (125 Ma) succession of Kutch, northwestern India: Tectonomagmatic implications |
| title_short | Rift-associated ultramafic lamprophyre (damtjernite) from the middle part of the Lower Cretaceous (125 Ma) succession of Kutch, northwestern India: Tectonomagmatic implications |
| title_sort | rift associated ultramafic lamprophyre damtjernite from the middle part of the lower cretaceous 125 ma succession of kutch northwestern india tectonomagmatic implications |
| url | http://www.sciencedirect.com/science/article/pii/S1674987117301949 |
| work_keys_str_mv | AT rohitpandey riftassociatedultramaficlamprophyredamtjernitefromthemiddlepartofthelowercretaceous125masuccessionofkutchnorthwesternindiatectonomagmaticimplications AT nvchalapathirao riftassociatedultramaficlamprophyredamtjernitefromthemiddlepartofthelowercretaceous125masuccessionofkutchnorthwesternindiatectonomagmaticimplications AT prashantdhote riftassociatedultramaficlamprophyredamtjernitefromthemiddlepartofthelowercretaceous125masuccessionofkutchnorthwesternindiatectonomagmaticimplications AT dineshpandit riftassociatedultramaficlamprophyredamtjernitefromthemiddlepartofthelowercretaceous125masuccessionofkutchnorthwesternindiatectonomagmaticimplications AT akchoudhary riftassociatedultramaficlamprophyredamtjernitefromthemiddlepartofthelowercretaceous125masuccessionofkutchnorthwesternindiatectonomagmaticimplications AT samarendrasahoo riftassociatedultramaficlamprophyredamtjernitefromthemiddlepartofthelowercretaceous125masuccessionofkutchnorthwesternindiatectonomagmaticimplications AT blehmann riftassociatedultramaficlamprophyredamtjernitefromthemiddlepartofthelowercretaceous125masuccessionofkutchnorthwesternindiatectonomagmaticimplications |