A Simplified Geology of the Perth Metropolitan Area

Home , Perth Basin

A Simpliﬁed Geology of the Perth Metropolitan Area

Fred Verheyde Geotechnical Principal / Branch Manager WA Geological Setting

Present

Perth 4.6 Ga: Birth of the Earth WA Geological Setting

Present

Pilbara Craton

Yilgarn P Craton

Perth 4.6 Ga: Birth of the Earth WA Geological Setting

Present

North Australian Craton WA Pilbara Craton

NA Y

Yilgarn P Craton

Perth 4.6 Ga: Birth of the Earth WA Geological Setting

Present d NUNA

Nuna North Australian Craton WA Pilbara Craton

NA Y

Yilgarn P Craton

Perth 4.6 Ga: Birth of the Earth WA Geological Setting

Present d NUNA

Nuna North Australian Craton WA Pilbara Craton SA

NA Y

Yilgarn South Australian Craton P Craton

Perth 4.6 Ga: Birth of the Earth WA Geological Setting

Present

d Gondwana Aus RHODINIA Rhodinia

Nuna North Australian Craton WA Pilbara Craton SA

NA Y

Yilgarn South Australian Craton P Craton

Perth 4.6 Ga: Birth of the Earth WA Geological Setting

Present

d Gondwana GONDWANA Aus Rhodinia

Nuna North Australian Craton WA Pilbara Craton SA

NA Y

Yilgarn South Australian Craton P Craton

Perth 4.6 Ga: Birth of the Earth WA Geological Setting

Present

d Gondwana Aus Rhodinia

Nuna North Australian Craton WA Pilbara Craton SA

NA Y

Darling Fault

Yilgarn South Australian Craton

P Exotic crust Exotic Craton

Perth 4.6 Ga: Birth of the Earth WA Geological Setting

Present

h d

Aus

Pilbara North Australian Craton WA

NA Y

Darling Fault Yilgarn.

P South Australian Craton Pinjarra Orogen Pinjarra A A' Perth 4.6 Ga: Birth of the Earth Deep Geology in the Perth Area

A A' Rot tnest Is. Perth Darling Scarp Darling Range

300 m A 60 m A' Earth Surface -30 m Ocean Perth Basin Oceanic -12 km crust Yilgarn craton Exotic crust A A' Magma -30 km

Magma Landform

Darling Range (Granitic rock of Yilgarn Craton)

Darling Scarp

(Darling Fault)

Gingin Scarp: Former foreshore

Coastal Plain: Pinjarra Plain (Guildford Formation) Bassendean Dune System (Bassendean Sand) Spearwood Dune System (Tamala Limestone and sand)

Quindalup Dune System (Safety Bay Sand) A' A Perth Ocean Perth Basin Oceanic crust Yilgarn craton

Exotic crust

Magma Geology / Landform

Surface Geology Landform

A A'

Perth Superficial Geological Formations A' A Perth Ocean A A' Perth Basin Oceanic crust Yilgarn craton

Exotic crust

Magma from upper mantle

Tamala A' Safety Bassendean Yoganup Limestone Bay Sand Sand Sand and sand Guildford Spearwood Dunes Bassendean Dunes Formation Perth A Quindalup Dunes Pinjarra Plain

0 m ocean Yilgarn Craton

-30 m Perth Basin Chronology of the Local Geology

Present 5 h d M yrs Young Old Aus 1 000 M yrs

WA Safety Tamala Bassendean Guildford Yoganup Bay Limestone Sand Formation Sand Sand and sand

200 10 000 100 000 180 000 2 500 000 Y 3 000 - - - - - M yrs 6500 420 000 800 000 1 800 000 5 000 000 ? yrs ? P Perth

Yilgarn ocean 0 m Craton

4.6 Ga: Birth of the -30 m Perth Basin 3 000 000 000 yrs Earth 65 000 000 - 300 000 000 yrs Safety Bay Sand

Quindalup Dune System

Safety Bay limestone Tamala Limestone and Sand

Quindalup Dune System

Sand derived from Tamala Limestone Tamala Limestone

Perth CBD Ocean Safety Bay Sand Bassendean Dunes Sand from Tamala Limestone Tamala Limestone

Tamala limestone Bassendean Sand Bassendean Sand

Sand derived from Tamala Limestone

Bassendean Sand

Coffee rock Guildford Formation 1,000,000 yrs ago (model) Yilgarn craton / Darling Range

Deposition of Guildford Formation in progress (Coalescent alluvial fans)

Perth coastal

plain

• Variable, alluvial Guildford Formation

• Variable, alluvial • Poor trafﬁcability, water management • Excavation • Locally blanketed by Bassendean sand The Hills

• Hard ground • Dolerite dyke • Erodibility Sea Level (Fremantle) Time before -300 000 -200 000 -100 000 present (yrs) +10 m 0 m (Present)

-50 m

-100 m -120 m -14 000 Sea Level yrs Paleo Sea Level

Humans in Perth

Modern humans on Earth

164 x earlier (-66 000 000 yrs) Extinction of dinosaurs Sea Level (Fremantle) Time before -300 000 -200 000 -100 000 present (yrs) +10 m 0 m • Fremantle: (Present) 1897-2004: 1.54 mm/yr 1992-2010: 4 mm/yr -50 m (consistent with global trend)

-100 m Global Sea Level Predictions -120 m -14 000 Sea Level yrs 'High Emission' scenario Paleo Sea Level 'Strong Mitigation' scenario

Instrumented records

Prediction

(Intergovernmental Panel on Climate Change, 2013 ) Sea Level (Fremantle) Time before -300 000 -200 000 -100 000 present (yrs) +10 m 0 m • Fremantle: (Present) 1897-2004: 1.54 mm/yr 1992-2008: 4 mm/yr -50 m (consistent with global trend)

-100 m Global Sea Level Predictions -120 m + 0.9 m ----> -14 000 Sea Level yrs Above today's level Paleo Sea Level + 0.4 m ---->

• State Coastal Planning Policy: Instrumented records • Untill 2010: 0.38 m sea rise for next 100 yrs. • 2013: 0.9 m over next 100 years, then 10 mm per year.

Prediction • Excludes extreme water levels.

(Intergovernmental Panel on Climate Change, 2013 ) Tamala Limestone - Caves

Two Rocks • Cavities occur in high strength limestone.

• Greater risk near groundwater level, in contact with acidic water, specific vegetation.

• City of Wanneroo local Planning Policy 4.13: Caves and Karstic Features

Yanchep Tamala Limestone - Karst Risk ‘Fissure Cave’ Tamala Limestone - Karst Risk ‘Fissure Cave’ Tamala Limestone - Karst Risk ‘Fissure Cave’ Tamala Limestone - Karst Risk �

200 mm

200 mm Thank you. Queries?

PILBARA KIMBERLEY

PERTH SOUTH WEST