revision

Reminders: 

Reminders Course work on notice board Consultation Hours (9-11am) Student evaluation form of GE306 course (SOLS) Exam 26 November Monday (2nd week of exams) 9.00am Vodafone Arena

Exam Format: 

Exam Format Three sections: Section A - Illustrated Answers 2 parts (6 questions each) Answer 8 questions at least 3 from each part Section B – Calculations (calculator allowed) Section C – Essay 4 essay questions Answer only 1 All SECTIONS are compulsory

Revision: 

Revision Chapter 1 Definition of Oceanic Islands Classification of islands 1st level classification 2nd level classification

Chapter 2: 

Chapter 2 Diagram (Layering of earth) figure 2.1 Sial, Sima, Moho Evolution of theories Steady state theory Earth surface mobility theory Alfred wegener (Continental drift theory, evidence, fall of this idea) Harry Hess (Sea floor spreading hypothesis, evidences, fall of the idea) Plate tectonics Model (theory, evidence)

Chapter 2 cont’d: 

Chapter 2 cont’d Plate Tectonics Divergent plate boundaries -MOR ( Iceland, MOR above ocean surface, hotspot, volcanism) -back arc basin (Niuafo’ou, triple junction, different from other Tongan Islands, how back arc basin) Convergent plate boundary -Terms (trench, accretionary prism, buoyant plate, down going plate, oceanic crust, benioff zone, island arcs) -volcanism (andesitic and basaltic) -volcanic arc and non volcanic arc (Tonga, ‘Eua) -Vanuatu (Fig 2.12)

Chapter 2 cont’d: 

Chapter 2 cont’d Transverse plate boundary (why, flower structure) Intra plate Boundaries Linear (hotspot hypothesis, age distance relationships, Samoa) Isolated and cluster (not included)

Chapter 3: 

Chapter 3 Terms (oceanic islands, seamounts and guyots) Under water volcanism (overburden squeeze) -MOR (Why not in the axes/ axial rift zone of MOR), seamounts, Laki fissure -Intraplate (sediment) Upward growth of underwater volcanoes Overlying water pressure, Extrusive products- (pillow lavas, breccias, sediment apron), Intrusion- (sills and plutons, La Palma) Characteristics of underwater volcanoes Summit and flank eruption, explosive and non explosive (why?), Hydroexplosive zone, change in eruptive products

Chapter 3 Cont’d: 

Chapter 3 Cont’d Formation of oceanic islands (Icelandic volcano of Surtsey) -Ocean surface eruption /shallow water eruption -critical factors( change in eruptive products, volume of material produced, rate of production of lava, marine and sub aerial processes of erosion)

Chapter 3 Cont’d: 

Chapter 3 Cont’d Erosion of oceanic volcanoes (intact volcano, planeze stage, Residual volcano, Volcanic skeleton) examples

Chapter 4: 

Chapter 4 Vertical movement (Uplift, subsidence) and tilting Isostacy Isostacy disturbed by Lithospheric temperature variation, Lithospheric flexure, lithospheric loading Vertical movement- Plate Boundary ( convergent and divergent) -Lithospheric flexure- C.P.B, Atoll Islands, coral cap, guyots, Niue, loyalty Islands -Lithospheric thrusting- C.P.B, frontal arc, underplating, Barbados Islands -Lithospheric temperature variation- D.P.B, Lau Islands

Chapter 4 cont’d: 

Chapter 4 cont’d Vertical movement- Intra Plate Boundary -Lithospheric temperature variation- lithospheric thickness, Tuamotu atolls -Lithospheric loading- moat, arc, cook islands, Tahiti, Hawaii Islands Uplift - Aseismic, seismic

Chapter 7 : 

Chapter 7 Types of reefs Fringing, barrier, atoll reefs Types of low reef Islands Cays, motu, low emerged reef islands Cays to Motu- beach rocks, vegetation Stabilization of Motu (kapingamarangi Atoll, Nui Atolls, Diego Garcia Atoll) -Resistance to erosion (beach rocks, conglomerate limestone, phosphate rock), no storms, vegetation

All the Best: 

All the Best