Lecture 7 CLIMATE DRIVERS OF THE NEOGENE: What is the Neogene: - Comprises of the Miocene, pliocene and Pleistocene. - It I difference from previous periods as has: o Changes in oceanic circulation o Configuration of the continents o Mountain building Earth's Interior o Climatic changes o Evolution of groups of plants and animals Inner Core Outer Core. Lower Mantle Plate Tectonics: Upper Mantle Crust - Earth's crust broken into at least 20 rigid plates - Each plate moves independently from others - Plates rest on a layer of heated, pliable rock called the asthenosphere - Asthenosphere: 3.3g/cm3 - it is plyable not ridged. Next slide 35 km 670 km (22 mi) (420 mi) Depth 1 2,900 km (1,800 ml) 5.200 km 6.371 km (3 200 ml) (3,959 ml) Plate tectonic forces: - Denser layers of crust sink beneath less dense layers - At edges of continents, when an oceanic plate collides with a continental plate, subduction occurs Oceanic crust (3.0 g/cm3) Continental crust (2.7 g/cm ) 0 Lithosphere 50 Rigid Asthenosphere (3.3 g/cm ) Plastic 100 150 Depth (km) Transition 200 zone Upper Mantle rigid 250 1300
- Denser oceanic crust sinks beneath lighter continental plates, this builds coastal mountain ranges Trench Slab pull Ridge Lithosphere Trench Mantle Asthenophere 700 km Outer Core Inner Core FRACTURE ZONE SHIELD VOLCANO Lithosphere Plate Asthenosphere (upper mantle) Where oceanic crust meets continental crust, the oceanic crust sinks beneath, forcing the edge of continental crust to rise and buckle t Where two oceanic plates move apart, you get fracturing o the crust, and oceanic ridges and volcanic islands form sea level continental crust trench oceanic crust volcano oceanic plate mantle (lithosphere) mantle (asthenosphere) magma generation Result of plate tectonic movements: - Supercontinents split apart - Continental pates change location on the globe - Seaways open up and close, changing oceanic circulation patterns