Elements at Muriwai

Pg 16 and 17

ELEMENTS

CURRENTS• Strong rip currents due to high energy beach• Force of waves sideways affect seafloor

TIDES• Highest tide is 4.3m (compared to 3.3m at St Leonards)• Occurs when sun and moon are in line and the gravitational pull is the greatest

(full moon)

SEDIMENT• 2 main types – black iron sand (titanomagnetite) and lighter coloured white

sand (quartz and feldspar). Only 5% produced by erosion, majority brought in by longshore drift from volcanic regions in the South

• Iron sand is smaller in diameter (0.25mm) compared to quartz grains (0.5mm) • Both are light enough to be picked up by the wind

ELEMENTS

ROCK TYPE• The headland is composed of Manuka Breccia which is a

conglomerate (mixture) of sandstone with volcanic intrusions

BIOTA• Headland vegetation is pohutukawa, manuka trees and flax

which have adapted to extreme weather conditions• Sand dunes have minimal vegetation. Spinifex, pingao and

marram grass grow on the dunes trapping sediment• Endangered tohera shellfish beds• Gannet colony on Motutara Stack• Fur seals on Oaia Island

WATER ELEMENTS

LAND ELEMENTS

CLIMATIC ELEMENTS

BIOTIC ELEMENTS

Wind Rose pg 17

• A wind rose is a diagram that tell us information about wind in an area. It tells us– Direction of wind– Force or speed of wind– How long the wind blew at that speed/direction

How to draw a wind rose pg 17

• Draw a small circle (or an octagon if you prefer) in the middle of page or area given

• Mark in your 4 main compass points with dashes• Calculate a scale e.g. 1cm = 5 knots• Draw a key e.g.

• Rule out bars in the direction wind blew for the length of time (%) it blew. Shade in bar the appropriate wind speed

3-15 knotsOver 15 knots

Climate Graph pg 18

• Plot the information given in the table at the top of page 18 on to the climate graph outline

• Look for some reminders of appropriate conventions of a climate graph on the next slide….

Rainfall is shown using a BAR graph and is shaded in BLUE

Temperature is shown using a

LINE graph and is done using RED

Title includes LOCATION and GRAPH TYPE

Left hand axis shows temp,

axis is labelled with

degrees celsius

Right hand axis shows rainfall. Axis is labelled with mm

Months are represented down the bottom with a letter

Points for the temperature are plotted in the MIDDLE of a column and joined with a SMOOTH curve

Significance of climate

• Below the climate graph write 2-3 sentences describing the significance of climate to the natural environment at Muriwai.