The Evolution of the Indian Ocean since the Late Cretaceous

1971/12/01 by Dan McKenzie, John G. Sclater · 936 citations
Biochemistry, Genetics and Molecular Biology · Earth and Planetary Sciences · #Geomagnetism and Paleomagnetism Studies #Geological and Geophysical Studies #Geology and Paleoclimatology Research #Lineation #Geology #Cretaceous #Paleontology #Ridge #Magnetic anomaly #Indian ocean #Continental drift #Period (music) #Upwelling #Geophysics #Oceanography #Tectonics

paper · pdf · doi:10.1111/j.1365-246x.1971.tb02190.x

published in Geophysical Journal International 24(5), 437-528 (Oxford University Press)

openalex publication_date 1971/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06

Abstract

Summary All available ship and aeroplane tracks across the Indian Ocean were searched for identifiable magnetic anomalies and transform faults, and hence the age and direction of motion at the time of formation of about two-thirds of the floor of the ocean established. The magnetic lineations show that India moved away from Antarctica at about 18 cm/y for 20 My in the Early Tertiary. This rapid motion ceased in the Eocene and was followed by a period in which little or no spreading took place west of the Ninety East Ridge. Australia separated from Antarctica during this period. The present spreading episode began about 36 My ago. This detailed study has permitted instantaneous poles of rotation to be obtained, and has established that Africa is now moving northward at 2cm/y relative to Antarctica in the South West Indian Ocean. The evolution of the triple junction between the South East, South West and Central Indian Ridges is clearly reflected in the topography and magnetic lineations. The depth of parts of the ocean formed since the Late Cretaceous increases with age in the manner expected from the temperature structure of a cooling plate, and supports the evolution determined from the magnetic lineations in a most remarkable way. Heat flow observations are more scattered but also consistent with the same thermal model. The proposed evolution agrees with the distribution of known continental fragments and with the Late Cretaceous palaeomagnetic poles from surrounding continents and one obtained from the shape of the magnetic lineations south of India. It is, however, not yet clear how to reconstruct Gondwanaland from the Late Cretaceous reconstructions.

Citations

• The fit of the continents around the Atlantic
• Magnetic Anomalies Over Oceanic Ridges
• Spreading of the Ocean Floor: New Evidence
• The Implications of Terrestrial Heat Flow Observations on Current Tectonic and Geochemical Models of the Crust and Upper Mantle of the Earth
• The North Pacific: an Example of Tectonics on a Sphere
• A New Class of Faults and their Bearing on Continental Drift
• Rises, trenches, great faults, and crustal blocks
• The Troodos Massif, Cyprus and other ophiolites as oceanic crust: evaluation and implications
• Sea-floor spreading and continental drift

Cited by

• Uncertainties and implications of the Late Cretaceous and Tertiary position of North America relative to the Farallon, Kula, and Pacific Plates
• A multiphase plate tectonic history of the southeast continental margin of Oman
• Tectonic evolution of the Southwest Indian Ocean since the Mid-Cretaceous: plate motions and stability of the pole of Antarctica/Africa for at least 80 Myr
• The Somalia plate and the East African Rift System: present-day kinematics
• Rodrigues triple junction [wikipedia]