Science : Year 8 - Geological Formations in Western Australia: Home

Deformation of rock involves changes in the shape and/or volume of these substances. Changes in shape and volume occur when stress and strain causes rock to buckle and fracture or crumple into folds. A fold can be defined as a bend in rock that is the response to compressional forces. Folds are most visible in rocks that contain layering.

There are usually only a few possibilities when two plates come up against each other, faulting, folding, a dip slip, and a strike slip. All of these events happen when two large pieces of land begin to move. Each type of interaction will give a unique geographical result that helps scientists understand earth movements deep below the surface.

You can trace the deformation a rock has experienced by seeing how it differs from its original horizontal, oldest-on-bottom position. This deformation produces geologic structures such as folds, joints, and faults that are caused by stresses.

Soil erosion remains a key challenge for Ontario agriculture. Many farmers have already made significant progress in dealing with soil erosion problems on their farms. However, because of continued advances in soil management and crop production technology that have maintained or increased yields in spite of soil erosion, others are not aware of the increasing problem on farmland. Awareness usually occurs only when property is damaged and productive areas of soil are lost.

Soil is the earth’s fragile skin that anchors all life on Earth. It is comprised of countless species that create a dynamic and complex ecosystem and is among the most precious resources to humans.
Half of the topsoil on the planet has been lost in the last 150 years. In addition to erosion, soil quality is affected by other aspects of agriculture. These impacts include compaction, loss of soil structure, nutrient degradation, and soil salinity. These are very real and at times severe issues.

With soil erosion, the top layer of soil is worn away due to factors such as water, wind and tillage of farmland. Learn about soil erosion and how natural elements and human activities break up and transport soil.

Travel two million years back in time and position yourself 200 km northeast of Shark Bay on the present-day Kennedy Ranges. All around you the sediments of an ancient long-dry seabed are weathering away and being carried to sea by a network of tributaries and rivers, or blown there by strong winds.

STRATIFICATION refers to the way sediment layers are stacked over each other, and can occur on the scale of hundreds of meters, and down to submillimeter scale. It is a fundamental feature of sedimentary rocks.

Stratification
Horizontal layering in sedimentary rocks is called bedding or stratification. It forms by the settling of particles from either water or air (the word sediment comes from the Latin sedimentum, meaning settled). Layer boundaries are natural planes of weakness along which the rocks can break and fluids can flow. As long as the sequence of layers has not been deformed or overturned, the youngest layers are at the top and the oldest are at the bottom

A few hours north of Perth, a cluster of ancient limestone rocks rise from the sand dunes as The Pinnacles Desert in Nambung National Park.

How were Pinnacles formed ?

The range is about 70 km long and 15 km wide, running east-west, separating the dry Wheatland to the north from the southern fertile agricultural land. Most of the high ground in the area are composed of granite, but the Stirlings are composed of sedimentary rocks such as sandstone, quartzite, slate and shale.

The Stirling Range or Koikyennuruff is a range of mountains and hills in the Great Southern region of Western Australia, 337 km south-east of Perth. It is over 60 km (37 mi) wide from west to east, stretching from the highway between Mount Barker and Cranbrook eastward past Gnowangerup

The Pinnacles are limestone formations within Nambung National Park, near the town of Cervantes, Western Australia.

The raw material for the limestone of the Pinnacles came from seashells in an earlier era that was rich in marine life. These shells were broken down into lime-rich sands that were blown inland to form high mobile dunes.

Click on each step to follow the process of the formation of the Pinnacles.

The surging power of the Southern Ocean is evident at The Gap, a spectacular channel in the 40m high coastal granites of Torndirrup National Park.

The Natural Bridge is a granite formation that looks just like a giant rock bridge! This 'bridge' is caused by the gradual wearing away of the granite rock by the Great Southern Ocean.

The Gap is an impressive rugged granite channel carved by the waves of the Great Southern Ocean crashing against the granite coastline forming a spectacular sheer drop of almost twenty five metres.

The area is composed of three major rock types, one of these being gneiss. The oldest of these was formed 1300-1600 million years ago. This rock type can be seen along the cliff walls of the Gap

Background to The Natural Bridge – For over one billion years Australia and Antarctica were actually joined together, forming part of a supercontinent called Gondwana.

Cave formations
Not only are the caves created by dissolving the limestone, they are decorated by it, too. Ground water that seeps back into the caves also has dissolved lime in it, and, as the water drips off the cave walls, and as it hits the floor below, it leaves a small deposit of lime, which, over thousands of years creates a range of fantastic forms

Speleothems, sometimes referred to as formations or decorations, are cave features formed by the deposition of minerals. The word speleothem is derived from the Greek words spelaion meaning "cave" and thema meaning "deposit". The speleothems with which most people are familiar are stalactites and stalagmites. Stalactites grow down from the cave ceiling, while stalagmites grow up from the cave floor. It’s easy to remember which is which: Stalactites have a "T" for top and stalagmites have a "G" for ground.

The island is characterised by alternating limestone headlands and bays with white sandy beaches. The coast is fringed by shoreline platforms and offshore ‘reefs’ formed by marine planation (levelling out of land surfaces)

Did you know that as well as sun, sand, and surf, the little rocky island of Rottnest has some geological features of international significance?

Contains photographs of the geological formations on Rottnest Island.

A quick introduction to igneous rocks including the ways in which they form and their identifiable physical characteristics like inter grown crystals and vesicular gas pockets.

Igneous Rocks are created from molten rock that is either on the surface (lava) or inside the Earth ( magma)

In-depth video about rock cycle and types of rocks. You will gain detail rock information and facts. We will also see the uses of rocks and minerals in our lives.

A brief introduction to sedimentary rocks including a look at how they form and the physical characteristics that they display, including layering, fossils, and compacted and cemented sediments.

Year 8 Sedimentary Rocks Video

A brief introduction to metamorphic rocks including a look at how they form as a result of exposure to intense heat and/or pressure. We will also look at their identifiable physical characteristics including foliation and banding.

in this video: we review the different ways metamorphic rocks forms and how that makes differences, as well as the rock cycle

How igneous, sedimentary, and metamorphic rocks are formed.

David Flannery explains the formation of living fossils known as stromatolites

This educational (non-profit) video was produced by Professor Drew Muscente for the Historical Geology course

The spectacular scenery of the Murchison River gorge is the result of many millions of years of geological activity. Hidden beneath the vast sandplain lies the ancient Tumblagooda Sandstone that formed 400 million years ago. The river has worn away this sandstone over millions of years, and carved out a stunning 80km gorge

Day walks in the Inland Gorges, Kalbarri.

Kalbarri is a 6 hour drive (590km) north of Perth. Kalbarri National Park's inland gorges can be accessed from both the west and east. Western access is from Kalbarri town, via Ajana-Kalbarri Road. Eastern access is off of the North West Coastal Highway, via Ajana-Kalbarri Road. The National Park's coastal cliffs are accessible off George Grey Drive.

Geology
The spectacular scenery of Kalbarri National Park is the result of many millions of years of geological formation. Beneath the landscape are deep, horizontal bands of multi-coloured sands which were deposited in layers some 400 million years ago.

Sedimentation, in the geological sciences, process of deposition of a solid material from a state of suspension or solution in a fluid (usually air or water). Broadly defined it also includes deposits from glacial ice and those materials collected under the impetus of gravity alone, as in talus deposits, or accumulations of rock debris at the base of cliffs. The term is commonly used as a synonym for sedimentary petrology and sedimentology.

Erosion is the transport by wind, water and ice of soil, sediment and rock fragments produced by the weathering of geological features. Sedimentation occurs when eroded material that is being transported by water, settles out of the water column onto the surface, as the water flow slows.

Deposition is the laying down of sediment carried by wind, water, or ice. Sediment can be transported as pebbles, sand & mud, or as salts dissolved in water. Salts may later be deposited by organic activity (e.g. as sea-shells) or by evaporation.

Weathering processes crack, wear away, and weaken rocks. Over time, it may cause large changes to the landscape. Physical and chemical weathering degrade rocks in different ways. While physical weathering breaks down a rock's physical structure, chemical weathering alters a rock's chemical composition. Physical weathering works with mechanical forces, such as friction and impact, while chemical weathering takes place at the molecular level with the exchange of ions and cations.

The primary difference between physical weathering and chemical weathering is that physical weathering occurs landforms like rocks, minerals and likewise substances are broken down by physical factors in the environment while chemical weathering occurs as a result of changes in the chemical composition of the minerals or rocks from exposure to the environment.

Quentin discovers Perth’s premier island getaway, Rottnest.

Adventure Awaits at Rottnest Island, just a 30 minute ferry ride from of Perth. Well known for its furry inhabitants, and world’s happiest animal – the quokka – you can also cycle around this car free paradise, visiting beautiful beaches and maybe spotting a whale or two!

Hyden Rock is an inselberg made up of variably textured, medium and coarse-grained porphyritic granite (igneous rock with embedded crystals). Inselbergs are created by the erosive action of wind and water over millions of years, and Wave Rock’s distinctive shape has been caused by erosion of the softer rock, which has undercut the base and left an overhang.

“Wave Rock is an upstanding part of a huge ancient crustal mass called the Yilgarn Craton,” says David Newsome, Professor of Geotourism at Murdoch University.

Stromatolite deposits are formed by sediment trapping and binding, and/or by precipitation activities of the microbial communities.

Stromatolite, layered deposit, mainly of limestone, formed by the growth of blue-green algae (primitive one-celled organisms)

Stromatolites, the commonest type of microbialites, are abundant in rocks older than 500 million years (which cover nearly two-thirds of the State), and are key fossils for understanding the origin and evolution of life

Stromatolites or stromatoliths are layered accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms of microorganisms, especially cyanobacteria (commonly known as blue-green algae). Stromatolites provide some of the most ancient records of life on Earth by fossil remains which date back more than 3.5 billion years ago.

The mountain was formed as the result an uplift which buckled, folded and tilted the rocks as it raised the ancient beds.

Mount Augustus is an ‘asymmetrical anticline’. Anticline means that rock layers have been folded into an arch-like structure – with the oldest layers at its core. Asymmetrical means that each side of the arch-like structure is not physically even or symmetrical, with Mount Augustus being steeper on its north-eastern side than the south-west side.

Mt. Augustus is a monocline (an asymmetrical anticline).

Metamorphic rocks are formed from other rocks that are changed because of heat or pressure. They are not made from molten rock – rocks that do melt form igneous rocks instead.

Metamorphic rocks are the rocks formed from other rocks. They are sedimentary or igneous rocks that have undergone changes as a result of extreme pressure and heat. The name defines their formation whereby ‘meta’ means change and ‘morph’ means ‘form.’ Hence, metamorphic rocks are those whose forms have been changed through geological process such as large tectonic movements and magma intrusions.

Metamorphic rock, any of a class of rocks that result from the alteration of preexisting rocks in response to changing environmental conditions, such as variations in temperature, pressure, and mechanical stress, and the addition or subtraction of chemical components. The preexisting rocks may be igneous, sedimentary, or other metamorphic rocks.

Purnululu (the Bungle Bungles) is by far
the most outstanding example of cone karst
in sandstones anywhere in the world. It owes its uniqueness to several interacting geological, biological, erosive and
climatic phenomena.

Bungle Bungle Range composed of Devonian-age quartz sandstone eroded over a period of 20 million years into a series of beehive-shaped towers or cones, whose steeply sloping surfaces are distinctly marked by regular horizontal bands of dark-grey cyanobacterial crust (single-celled photosynthetic organisms).

The story of the Bungle Bungles begins about 360 million years ago with a river not so different from the Ord River that flows nearby today. That river flowed downhill towards the ocean until it hit a broad low basin. There, it spread out, slowed down and deposited its load of sediment before drying up.