C. Geology of ocean basins

C. Geology of ocean basins

C.1 Coastal dynamics

Nature of science:

• Scientists use observed and measured patterns to form explanations and make predictions.

Understandings:

• The coastal zone has different definitions

• Physical factors that affect the coast zone are the substrate, topography, wind, waves, longshore currents and littoral drift that shift with the seasons

• Beaches, barrier islands, sandbars, barrier reefs, fringing reefs, cliffed headlands, estuaries, lagoons, bays, and salt marshes are coastal features

• Tide zones describe coasts

• Coastlines of the Pacific Rim are affected by tectonic activities

• Sediment formation, erosion, transport and deposition are active process of apparently static beaches

• Sea waves are refracted toward headlands and away from coves and bays

• Waves approaching at an angle produce beach drift

Applications and skills:

• Skill: Drawing and annotating a generalized topographic profile of a coastal zone.

C.2 Sediments and oozes

Nature of science:

• Looking for patterns, trends and discrepancies

• Scientists use classification systems to develop observations leading to generalizations

Understandings:

• Terminology that describes sources, composition, and sizes of sediments

• Characterize biogenous, lithogenous, hydrogenous and cosmogenous sediments as well as calcareous and siliceous oozes

• Rates of accumulation vary

• Accumulated sediments and oozes provide a history of the basin

• Coastal sediments shift in response to currents, waves and storms seasonally and sporadically

• Deep sea core sampling verifies seismic profiling

• Commercial importance of neritic and pelagic sediments

Applications and skills:

• Skill: examining sediments as to composition

• Skill: measuring sediments and apply Wentworth scale

• Skill: comparing sand samples from different beaches

C.3 Mining the ocean floor

Nature of science:

• Scientists analyse data and look for patterns, trends and discrepancies, attempting to discover relationships and establish causal links.

Understandings:

• Seismic profiling and deep-sea core sampling have identified mineral resources worth mining on the ocean floor.

• Among the resources identified are oil, natural gas, sulfide deposits, placer deposits of iron, tin, platinum, gold and diamonds

• Gravel, shells and sand are mined to build roads

• Ocean mining is hazardous and expensive

Applications and skills:

• Skill: Examining a seismic profile and/or core sample to find evidence of exploitable resources

• Application: Oil pollution in the Gulf of Mexico

• Application: the oil spill by the Exxon Valdez in the Gulf of Alaska

C.4 Human activity and marine disasters

Nature of science:

• Investigating the relationship between human activities to mitigate marine hazards, has taken the form of trial and error.

Understandings:

• There is increasing human development along coastlines including docks, ports, resorts, recreational facilities, growing cities, roads, etc.

• Forces of nature that are in conflict with human activity include storm surges, oceanic storms, rising sea level, and littoral drift

• Human activity has removed natural coastal features such as dunes, wetlands, mangrove forests, as well stabilizing river deltas and straightening rivers so that the original natural safeguards from ocean hazards have been removed.

• Shipping, fishing, mining and travel across oceans have lead to disasters especially during storms.

• Building of levees, dikes, jetties, groins, breakwaters, dams and sea walls has had variable success.

• Artificial replacement of beach sand is a short term solution.

Applications and skills:

• Skill: designing and testing models to explore the effectiveness of a structure to prevent beach erosion, survive an earthquake or a flooding event on a coast.

• Application: chart the movement of debris from the Japanese tsunamis of 2011 (shipping accidents or other event) and its arrival on the west coast of North America. Consider the consequences of this information.

C.5 Using science to understand marine catastrophes

Nature of science:

• Scientists work to assist with disaster preparedness by creating models to solve problems and improve man's lot.

Understandings:

• In coastal communities likely to be affected by tsunamis, procedures are in place to avoid loss of life and property.

• Warning systems are in place to predict the arrival time and magnitude of tsunamis yet some areas of the world are under-served by these systems.

• Steps to prepare for or limit damage vary from community to community

• Disasters are measured, risks analysed, interventions are made

• Structures such as sea walls have limits to their effectiveness.

Applications and skills:

• Skill: developing testable models to alleviate components of coastal disasters.

• Application: Choose a place with tsunami damage and describe the nature of the tsunami event(s), what was done to prepare for the disaster, what relief was provided, and what plans have been made for the future.