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Annual General Meeting and Student Medal Presentations + Monthly Talk

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Kings Park Admin Centre; Botanic Gardens and Parks Authority Building

1 Kattidj Close

Kings Park

Perth, WA 6005

Australia

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Annual General Meeting and Student Medal Presentation, followed by “350 million year history of the Indian Ocean and precursor seas" by Professor David Haig (Retiring RSWA President)

Monday, 19th August 2019

5.30 pm Kings Park Administration Building, Fraser Avenue

Free admission

ITEMS OF AGM BUSINESS (Constitution clauses 50 to 52)

  1. Minutes of the previous Annual General Meeting
  2. Annual Report of the Council
  3. Treasurer’s Report presenting the Financial Statements and Auditor’s Report
  4. Election of Council for 2017-2019 (Constitution clauses 26 and 27)
  5. Presentation of the RSWA Student Medals
  6. Presentation from Retiring President David Haig

Earth is subject, on various scales, to cycles of change. One of the most profound of these is the opening and closing of an ocean, generally on a time scale of hundreds of millions of years. From a fractious but hesitant opening to the beginnings of a cataclysmic end, the Indian Ocean is reviewed from a personal Western Australian perspective. The precursor history of the Indian Ocean lies in the East Gondwana Interior Rift with axial basins along which the Ocean eventually opened, and marginal rift basins that splayed from the main rift axis. Deposits of these basins reveal a history of salty warm shallow seas followed by rapid cooling and formation of Antarctic-like ice sheets which melted in a rapid and dramatic way releasing in places methane seeps on the sea floor (at about 295 million years ago). Several major mass extinctions punctuated the ever changing habitats of the interior seas. The Indian Ocean opened first in the north (165 million years ago), and then the ocean-forming rifting progressively moved south during an interval of about 30 million years, creating the present-day margin of the Australian continent. Sea-level fluctuated with transgressions and regressions across the continental shelf, and with an extreme marine flooding covering about 60% of the present Australian mainland about 100 million years ago. At about 56 million years ago, a modern-looking subtropical to tropical marine biota first inhabited the continental shelf, and the first widespread seagrass meadows appeared at around 20 million years ago. In the north, the passive tropical continental margin of Australia collided with island arcs and microcontinents in the New Guinea region at about 23 million years ago. At about 8 million years ago, the western Australian continental margin started to collide with the leading edge of the Asian continent in a series of cataclysmic phases that represent the initial stages of the demise of the Indian Ocean.

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Date and Time

Location

Kings Park Admin Centre; Botanic Gardens and Parks Authority Building

1 Kattidj Close

Kings Park

Perth, WA 6005

Australia

View Map

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