The Hydrologic System and the Tectonic System 2. Geologic Systems The Hydrologic System and the Tectonic System

What is a Natural System? Group of natural, interdependent parts or components Interactions between parts forms the system Forces drive the system All systems tend toward a state of lowest energy (or maximum disorder--entropy) called equilibrium Earth’s two major systems are: Hydrologic System Tectonic System

Equilibrium in Geologic Systems Analogous to gravitational potential energy All geologic systems strive to minimum energy state Winter (2001)

Hydrologic System System of moving water Hydrologic System Rivers Oceans, Lakes Glaciers Groundwater Water Vapor in Atmosphere Hydrologic System Erosion Transportation of Sediment Deposition of Sediment Creation of Numerous Landforms

Hydrologic System

What Forces Drive this System? Solar Radiation Average ~342 W/m2 = ~342 joules/sec m2 Causes evaporation Gravity Pulls water down slopes Causing erosion, transportation of sediment Atmospheric convection

Global Patterns in the Hydrologic System How does atmospheric circulation affect the movement of water in the hydrosphere? Where will air rise? Where will air sink? What holds more water vapor? Cool air or hot air

Uneven Solar Heating Dr. Kowallis -- Geology 330

Dr. Kowallis -- Geology 330

Magnitude of Hydrologic System Imagine what would happen if water delivered to the continents stopped going back to the sea Sea level would drop …..

Magnitude of Hydrologic System Imagine what would happen if water delivered to the continents stopped going back to the sea Sea level would drop 1 m/y Has this ever happened?

Magnitude of Hydrologic System Imagine what would happen if water delivered to the continents stopped going back to the sea Sea level would drop ~1 m/y Has this ever happened? During last ice age Siberia and Alaska connected England and France connected New York City 100 km inland

Where is Water Found in the Hydrologic System? Oceans 97% Of that not in Ocean Ice 80.0% Lakes 0.7% Rivers 0.005% Atmosphere 0.0001% 97% Dr. Kowallis -- Geology 330

Subsystems of the Hydrologic System River Systems Glacial Systems Groundwater Systems Shoreline Systems Eolian Systems Each creates Landforms Bodies of rocks Operation of Energy on Matter Dr. Kowallis -- Geology 330

Dr. Kowallis -- Geology 330

Hydrologic System: Summary A natural system is a group of interdependent components that interact to form a unified whole and are under the influence of related forces. The materials in a system change in an effort to reach and maintain equilibrium. Earth's system of moving water--the hydrologic system--involves movement of water in rivers, as groundwater, in glaciers, in oceans, and in the atmosphere. Heat from the Sun is the source of energy for Earth's hydrologic system. Gravity drives it downhill. The distribution of solar energy creates a vast global pattern of convective transport of water vapor. As water moves, it erodes, transports, and deposits its sediment, creating distinctive landforms and rock bodies. Earth has a dynamic hydrologic system because of its composition (i.e., water-rich), its size (able to hold out gassed vapor), and its distance from the Sun (warm enough for liquid water to exist over much of its surface yet cold enough for ice at the poles and high latitudes).

Earth’s Tectonic System

Tectonic System A system of moving plates of lithosphere sliding over the weak asthenosphere Movement driven by convection and Earth’s internal hear Radioactive decay of K, U, and Th Heat released as Earth tries to reach equilibrium with cold space

Tectonic System

Plate Boundaries

Divergent plate boundary Midocean ridge

Divergent Plate Margins Rifted continent Mid-oceanic ridge with subsiding rift margins

Divergent Plate Boundaries Continental rifts Midocean ridges New ocean basins Volcanoes Shallow earthquakes

Tectonic System: Convergent plate margins

Convergent plate margin: Ocean-Continent Andes Mountains

Convergent Plate Margins Oceanic-Continental Subduction Zone Volcanoes in a continental arc Cascade Range, NW USA

Mexican Volcano: 2003

Convergent Plate Boundaries Folded mountain belts on continents Deep sea trenches Volcanic chains on continents Volcanic island arc in oceans Abundant earthquakes—shallow to deep

Tectonic System: Transform Plate Margin

Transform plate boundaries Long, straight faults Movement is horizontal Shallow earthquakes are abundant

Dr. Kowallis -- Geology 330

Mantle plumes

Dr. Kowallis -- Geology 330

Mantle Plumes: Hot spots Not plate boundaries Rising plumes of hot mantle material Within plate volcanoes Broad flexures of lithosphere

Earth’s Tectonic System