The ocean basins receive a constant.

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• The ocean basins receive a constant.

• At depths of lt4000m the fine sediment is
  enriched
• with the remains of microorganisms,

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Avg. rate of deposition on ocean floor
tells us that the younger sediments will be
found on top, and are progressively older as you
go deeper.
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Ocean floor sediments remains of plankton and
other marine life on the ocean floor

• certain characteristics of these
• remains can give clues about
• ocean temperature and chemistry
• at the time of their formation

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3 oxygen isotopes 18O, 17O, 16O 2 isotopes of
hydrogen 1H, 2H
(thus, water has 9 different possible
combinations) 1H216O makes up 99 of ocean
water 1H218Omakes up lt1 of ocean water
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in the calcium carbonate (CaCO3) of
plankton tests species foraminifera (forams)
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• during glacials, oceans become
• during interglacials, oceans become

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• when the 18O levels were plotted with depth
  (age)
• of the ocean sediment, it was recognized that
• the
• (lecture 5)

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• these may indicate dry periods on continents,
• wind direction, or wind intensity

Dust Storm Gobi Desert
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Terrigenous sediments also include material
transported by icebergs broken off from
continental ice sheets
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• In the 1980s, layers of ice-rafted debris were
• found across the floor of the North Atlantic

as you move towards the east away from
their source in North America
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• Layers consist of
• Layers contain many
• (sand carried by rivers stays
• along the coast)

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What is the significance of Heinrich events?

• they occurred at the same time as the abrupt
  climate change of the

• They provide evidence that the North
• Atlantic was

YD
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• Ocean conveyor belt showing
• North Atlantic heat pump