Refine your search
Collections
Co-Authors
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z All
Balasubrahmanyan, M. N.
- Geochronology of the Jammu Limestone, Udhampur District, Jammu & Kashmir State, India
Abstract Views :186 |
PDF Views:285
Authors
Affiliations
1 Geological Survey of India, Calcutta, IN
1 Geological Survey of India, Calcutta, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 19, No 5 (1978), Pagination: 221-223Abstract
No Abstract.Full Text
- K-Ar Ages of Indian Kimberlites
Abstract Views :218 |
PDF Views:138
Authors
Affiliations
1 Geological Survey of India, Calcutta, IN
1 Geological Survey of India, Calcutta, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 19, No 12 (1978), Pagination: 584-584Abstract
No Abstract.Full Text
- Rb-Sr Chronology of the Khetri Copper Belt, Rajasthan
Abstract Views :208 |
PDF Views:3
Authors
Affiliations
1 Physical Research Laboratory, Ahmedabad 380009, IN
2 Geological Survey of India, 29, Jawaharlal Nehru Road, Calcutta 700 016, IN
3 Geological Survey of India, Bhutan Circle, Samchi, BT
4 Geological Survey of India, Geochronology and Isotope Geology Division, 29, Jawaharlal Nehru Road, Calcutta 700016, IN
1 Physical Research Laboratory, Ahmedabad 380009, IN
2 Geological Survey of India, 29, Jawaharlal Nehru Road, Calcutta 700 016, IN
3 Geological Survey of India, Bhutan Circle, Samchi, BT
4 Geological Survey of India, Geochronology and Isotope Geology Division, 29, Jawaharlal Nehru Road, Calcutta 700016, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 20, No 9 (1979), Pagination: 450-456Abstract
Rubidium and strontium determinations are reported for the Udaipur and Saladipura granites from the Khetri copper belt. The whole-rock data define a Rb-Sr isochron corresponding to an age of 1480 ± 40 m.y. and initial Sr ratio of 0.7131 ± 0.006. This age is older than previously believed, but consistent with the generally high age of post-Delhi intrusive rocks so far dated in the region. Biotites associated with these rocks give younger ages around 700 m.y, This indicates mobilisation of Sr isotopes in a later metamorphic event. It is significant that this secondary event is almost synchronous with the intrusion of granites to the west and south of the Aravalli mountains.
- Lamprophyres from Indian Gondwanas - K-Ar Ages and Chemistry
Abstract Views :177 |
PDF Views:2
Authors
Affiliations
1 Geochronology and Isotope Geology Division, Geological Survey of India, 29, Jawaharlal Nehru Road, Calcutta 700 016, IN
2 Chemical Laboratory, Geological Survey of India, 27, Jawaharlal Nehru Road, Calcutta 700016, IN
1 Geochronology and Isotope Geology Division, Geological Survey of India, 29, Jawaharlal Nehru Road, Calcutta 700 016, IN
2 Chemical Laboratory, Geological Survey of India, 27, Jawaharlal Nehru Road, Calcutta 700016, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 21, No 4 (1980), Pagination: 188-193Abstract
Lamprophyric dyke rocks occurring in the Indian Gondwanas (Permian-Lower Cretaceous) form a consanguinous suite ranging from ultrabasic mica-peridotite to micro-syenitic assemblages. Chemical characters include low SiO2 (ca. 40% or less), high (FeO+MgO) and high MgO/FeO and K2O/Na2O ratios. The petrographic and chemical characters have been discussed in a broad framework after Rock (1977). K-Ar radiometric ages on four biotite separates and one whole rock from three different localities range from 105 to 121 Ma and are believed to represent true crystallisation ages.- New Rb-Sr Age of Kanara Granite, South Kanara District, Karnataka State
Abstract Views :195 |
PDF Views:150
Authors
M. N. Balasubrahmanyan
1,
P. K. Bishui
1,
K. C. Chandy
1,
S. N. Gupta
1,
N. K. Jana
1,
D. K. Paul
1,
R. Prasad
1
Affiliations
1 Geochronology and Isotope Geology Division, Geological Survey of India, Calcutta, IN
1 Geochronology and Isotope Geology Division, Geological Survey of India, Calcutta, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 23, No 8 (1982), Pagination: 402-405Abstract
New Rb-Sr isotopic age is presented for the porphyritic phase of Kanara batholith of South Kanara, Karnataka. The porphyritic granite has a good spread of Rb/Sr ratio and indicates an isochron age of 2681 ± 236 Ma with an initial ratio of 0.7022 ± 0.004. The observed low initial Sr ratio suggests its derivation from mantle without much crustal contamination.Full Text