Elements at Muriwai Pg 16 and 17
May 20, 2015
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.