Australia: Western Australian – Lake Clifton Thrombolites

🌍 A Little Background — What on Earth Are We Looking At?

There are moments in life when you find yourself standing in front of something that makes you feel genuinely, profoundly small. Not in a bad way — more in the way that a very old cathedral does, or the first time you see the Grand Canyon and realise that photographs have been lying to you your whole life. Lake Clifton, tucked inside Yalgorup National Park about 90 kilometres south of Perth in Western Australia, does exactly that. The park itself sits on the Yalgorup Plain between the Indian Ocean and the Darling Scarp, a stretch of coastal wetland that looks, at first glance, like rather a lot of not very much. Scrubby trees, shallow lakes, the occasional bird doing something aerobatic. Nothing to get particularly worked up about. And then you walk down a modest timber boardwalk to the edge of a lake and see them — the thrombolites — and you think, right, well, I was not expecting that.

Thrombolites are, in the very plainest terms, living rocks. They are microbial structures built up over extraordinarily long periods of time by communities of cyanobacteria — microscopic organisms that are, quite frankly, the oldest form of complex life on this planet. The cyanobacteria trap and bind sediment particles and also precipitate calcium carbonate, slowly accumulating into mound-like formations that can take centuries to grow just a few centimetres. The ones at Lake Clifton are reckoned to be among the largest and most significant living thrombolite communities in the world, and some of the structures in the lake are thought to be around 2,000 years old. Two thousand years. While the Romans were arguing about who should run the empire, these lumpy grey things were quietly getting on with being alive in a lake in Western Australia, and they have not stopped since. It is, if you stop to think about it, rather humbling.

🪨 The Science Bit — Stick With It, It’s Worth It

Cyanobacteria — formerly called blue-green algae, though they are not algae at all, which tells you something about how science occasionally gets ahead of itself and then has to apologise — have been around for somewhere between 2.7 and 3.5 billion years. To put that in perspective, the dinosaurs only showed up about 230 million years ago, had their moment, and then largely disappeared. Cyanobacteria were ancient news by then. These organisms are credited with one of the most consequential events in Earth’s history: the Great Oxidation Event, which occurred roughly 2.4 billion years ago, when cyanobacterial photosynthesis began pumping oxygen into what had previously been a largely oxygen-free atmosphere. In other words, the reason you can breathe right now is, in no small part, down to the ancestors of the organisms sitting in Lake Clifton. You are welcome to feel grateful.

The thrombolites at Lake Clifton were first formally documented by scientists in the 1980s, though the Bindjareb Noongar people, the traditional custodians of this land, had known of them long before any scientist turned up with a clipboard. The Noongar connection to the Yalgorup region stretches back tens of thousands of years, and the wetlands held considerable cultural and spiritual significance. The name Yalgorup itself is understood to derive from the Noongar language, broadly meaning “land of the swamps.” Lake Clifton is a coastal plain lake that sits above a thin freshwater lens floating over a base of hypersaline groundwater, and it is this particular hydrological peculiarity — the mixing of freshwater and saline conditions — that creates the chemistry in which thrombolites can form. It is a remarkably precise set of circumstances, and the thrombolites are therefore quite picky about where they live. They do not, for example, grow in places where humans have fiddled excessively with the hydrology. Which is, of course, exactly what has been happening in parts of the Yalgorup system for several decades, as agricultural drainage and urban development have altered the groundwater balance. The thrombolites, being rather set in their ways after two millennia, have not found this helpful.

🚶 Getting There and Being There — The Actual Visit

Yalgorup National Park was formally gazetted in 1973, which in geological and biological terms is the equivalent of someone putting up a small sign that says “do not touch” about thirty seconds before closing time. The park covers around 13,000 hectares and contains ten lakes, but it is Lake Clifton and its thrombolites that bring most visitors down the Old Coast Road through Mandurah and into the park’s northern section. The drive itself is pleasant without being spectacular — flat, coastal, the kind of landscape that Australia does very well and that takes a little while for a person used to England’s insistence on hills and drama to properly appreciate. You park in a small, unremarkable car park, follow the signs, walk along the boardwalk, and then there they are. Hundreds of dark, rounded, barnacled-looking lumps sitting in the shallows of a lake that is not deep enough to drown a determined labrador. They sit between a few centimetres and about a metre above the lake bed, and in the right light — particularly morning light — they have an eerie, ancient quality to them that no photograph ever quite manages to capture.

The boardwalk stretches for around 350 metres along the lake’s eastern shore and was constructed specifically to allow visitors to get close enough for a proper look without actually stepping into the lake, which would be both ecologically catastrophic and, one imagines, rather frowned upon by the park rangers. There are information panels along the way, written in that upbeat but earnest style that national parks the world over have apparently all agreed upon, and they do a good job of explaining what you are looking at without making you feel as though you are doing homework. The thrombolites here were the subject of significant scientific interest in the late 1980s and through the 1990s, with researchers from institutions including the University of Western Australia studying their microbial communities and their geological significance. Studies published in that period helped establish Lake Clifton as one of the most important thrombolite sites on Earth — a distinction it shares with places like Hamelin Pool in Shark Bay, several hundred kilometres to the north, where the structures are stromatolites rather than thrombolites, a distinction involving their internal fabric that is deeply meaningful to microbiologists and essentially invisible to everyone else.

🧬 Why It Matters — The Bigger Picture

The thrombolites of Lake Clifton matter for reasons that go well beyond the fact that they are ancient, which is already reason enough. They represent a functioning, living example of a biological system that was responsible for making the Earth habitable, and they are doing it today, right now, in a shallow lake beside a road in Western Australia. Photosynthesis is happening. Calcium carbonate is being precipitated. Tiny organisms are going about their business in the same way they have for billions of years, largely indifferent to the fact that a retired English bloke is standing on a boardwalk looking at them with a slightly bewildered expression. There is something genuinely philosophical about that, if you are in the mood for philosophy, which standing by a quiet lake in the Australian morning air rather encourages.

The threats to the Lake Clifton thrombolites are real and have been the subject of increasing concern since at least the 1990s. Changed hydrology, altered nutrient levels from surrounding agricultural land, the invasion of exotic fish species — particularly the mosquitofish, Gambusia, introduced to Australia in the 1920s ostensibly to control mosquitoes and which has since made itself extremely unwelcome in virtually every freshwater system it has entered — and the broader effects of a drying climate in south-western Australia have all placed pressure on the lake’s ecosystem. The region’s rainfall has declined measurably since the mid-1970s, and the groundwater levels that sustain the lake’s unique chemistry have fallen accordingly. The Western Australian government and various research bodies have undertaken monitoring programmes over the years, and the thrombolites remain, for now, alive and active. But they are not invulnerable, and the combination of pressures they face is a reminder that things which survived two billion years of geological upheaval can still be undone by a century of human carelessness. The lake has outlasted almost everything. It would be a considerable shame to be the generation that finally got to it.

🌅 Leaving Lake Clifton — A Final Thought

We left Lake Clifton mid-morning, having spent what felt like a long time standing at the end of the boardwalk saying nothing very much, which is a sure sign that something has genuinely got through. It is not a place that announces itself loudly. There is no gift shop, no dramatic scenery, no obvious attraction in the way that a waterfall or a canyon is an obvious attraction. It asks a little something of you — a willingness to stop, to look at something that does not immediately explain itself, and to recalibrate your sense of what is old and what is remarkable. The drive back up through Mandurah was quiet, in the way that drives sometimes are after you have seen something that needed thinking about. The thrombolites were still there behind us, as they were before us, doing what they do, which is essentially nothing visible and everything important, at roughly the pace of geological time. It seemed right to leave them to it.

Planning your visit to Yalgorup National Park

🌿 Overview

Yalgorup National Park is the largest national park on the Swan Coastal Plain in Western Australia, covering approximately 13,140 hectares of coastal lakes, tuart woodlands, paperbark swamps and limestone ridges. Its name derives from two Noongar (Nyoongar) Aboriginal words — yalgor, meaning swamp or lake, and up, meaning place — making it, quite simply, the “place of lakes.” The Pinjarup people are recognised as the Traditional Owners of this land, and their deep connection to it stretches back thousands of years.

The park was first gazetted as a national park in 1968, with additional lake systems incorporated in 1971. It is home to a chain of ten hypersaline and brackish lakes, including Lake Clifton, Lake Preston, Lake Pollard, Lake Hayward and Martins Tank, whose depressions lie between a series of ancient coastal dunes running parallel to the Indian Ocean shoreline. The park is an internationally recognised Ramsar wetland of global importance, supporting migratory waterbirds and numerous threatened plant and animal species.

🪨 The Thrombolites of Lake Clifton

The undisputed highlight of Yalgorup National Park is the remarkable thrombolite reef at Lake Clifton — one of the most significant and scientifically important natural features in Western Australia, and among the rarest on Earth.

Thrombolites are living, rock-like structures built by communities of micro-organisms, primarily cyanobacteria, that are too small to be seen with the naked eye. They form through the precipitation of calcium carbonate as the micro-organisms photosynthesise, slowly building mineralised dome or column-shaped mounds. The thrombolites at Lake Clifton are around 2,000 years old, yet the organisms responsible for creating them trace their ancestry back more than 3,500 million years — to a time when microbial life first began releasing oxygen into the Earth’s primordial atmosphere, paving the way for all subsequent life. They are, in the truest sense, living relics of the dawn of life on our planet.

The Lake Clifton thrombolite reef is the largest in the southern hemisphere, extending in a strip roughly 30 metres wide over five kilometres along the eastern shoreline. The individual formations typically measure between 40 centimetres and one metre in diameter, and support their own ecosystem — providing food and shelter for invertebrates such as crustaceans and molluscs, as well as protected frog and tortoise species. Scientists believe the thrombolites flourish here because Lake Clifton receives upwellings of fresh groundwater that is naturally high in calcium carbonate.

Because the thrombolites are extraordinarily fragile, a dedicated timber observation boardwalk has been constructed at the lake’s edge, allowing visitors to view these formations at close quarters without causing damage. Interpretive signage along the boardwalk explains the science, the geological significance and the Aboriginal cultural connections of this place. The thrombolites are most visible when lake water levels are lower, typically between January and May, though the site is rewarding to visit year-round.

📍 Location

Yalgorup National Park lies on the Swan Coastal Plain between Mandurah and Bunbury, approximately 80 minutes south of Perth, 45 minutes south of Mandurah and 45 minutes north of Bunbury. The park stretches south from the Dawesville Channel to Myalup.

The thrombolite viewing area at Lake Clifton is accessed via Old Coast Road, heading south from Mandurah. Turn right onto Mount John Road and follow it to the car park just past Cape Bouvard Winery. The site is signposted from the main road. A standard two-wheel-drive vehicle is suitable for all main access routes.

A Park information bay is also located at the beginning of Lake Preston Road, Myalup, at the southern end of the park.

🌐 Website

Full visitor information, trail maps, campsite bookings and park alerts are available through the official Explore Parks WA website:

https://exploreparks.dbca.wa.gov.au/park/yalgorup-national-park

📞 Contact

The nearest Parks and Wildlife Service office is the Mandurah Work Centre, managed by the Department of Biodiversity, Conservation and Attractions (DBCA):

Mandurah Work Centre 423 Pinjarra Road, Mandurah WA 6210 PO Box 1266, Mandurah WA 6210 Telephone: (08) 9303 7750 Office hours: Monday to Friday, 8:30 am to 4:30 pm (closed weekends and public holidays)

For general enquiries to the Department of Biodiversity, Conservation and Attractions: Telephone: (08) 9219 9000 (Monday to Friday, business hours)

🎟️ Entry Fees

Entry to Yalgorup National Park is free of charge. There are no vehicle entry fees applicable to this park.

Camping at Martins Tank Campground does incur a fee, and bookings are essential. Campers must have a confirmed booking; day-use without a booking is not permitted at the campground. Bookings can be made through the Explore Parks WA website.

🕐 Opening Times

Yalgorup National Park is open to day visitors at all times. There are no set opening or closing hours for the park itself or the thrombolite boardwalk at Lake Clifton.

The Martins Tank Campground operates on a bookings-only basis; contact the Mandurah Work Centre or book online for availability.

🚶 Walking Trails

The park offers several well-maintained walking trails suitable for a range of abilities:

Lake Clifton Loop Trail — An easy 5-kilometre loop running alongside the eastern shore of Lake Clifton, passing paperbarks, melaleucas, peppermints and tuarts. The thrombolite boardwalk is accessed at the start of this walk.

Lake Pollard Loop Trail — A 6-kilometre, approximately two-hour circular walk beginning near the Martins Tank Campground entrance. The trail passes tuart, peppermint and grasstree outcrops and includes access to a bird hide overlooking Lake Pollard.

Heathlands Walk Trail — A 4.6-kilometre loop featuring a gentle climb over a limestone ridge with views across Lake Preston, before descending through a tunnel of trees to the water’s edge.

Lime Kiln Lake Trail — A short 1.4-kilometre return walk tracing the remnants of a lime kiln operation from the early 1920s, leading through peppermint and melaleuca woodland to the edge of Lake Clifton.

🐦 Wildlife and Nature

More than 134 bird species have been recorded within the park, making it exceptional for birdwatching. Visitors may encounter black swans, kingfishers, parrots and various species of dotterel, as well as migratory waterbirds from across the Asia-Pacific flyway. A bird hide at Lake Pollard offers a sheltered vantage point for observation.

Kangaroos are commonly seen throughout the park. The chuditch (western quoll), southern brown bandicoot and ringtail possum also inhabit the area. Several orchid species flower in the swampy ground during late winter and early spring. Lake Preston is notable for being approximately nine times more saline than the ocean.

⚠️ Visitor Information and Rules

There is no access to the lakes for swimming, canoeing, kayaking, boating or fishing. The lake-shore environment is fragile, and contact with the water is discouraged for health reasons.

No rubbish bins are provided throughout the park; visitors must carry all waste out with them.

Pets are not permitted anywhere in the park.

The Department of Biodiversity, Conservation and Attractions undertakes ongoing 1080 baiting within the park to control feral cats and foxes. The 1080 poison is lethal to domestic animals and hazardous to humans; visitors should heed all warning signs.

Fire restrictions apply throughout the park. Fires are only permitted in communal fire pits and only outside the declared fire ban season.

Visitors are encouraged to download the free Emergency+ app before their visit and to consider carrying a personal location beacon (PLB) when exploring more remote areas of the park.

⛺ Camping

Martins Tank Campground is nestled amongst peppermint woodland and tuart forest on the banks of Martins Tank Lake. It caters for tent campers as well as caravan and camper trailer users. Bookings are essential and must be made in advance through the Explore Parks WA website. Picnic facilities are not provided at the campground itself, but a picnic area is located approximately one kilometre away at the Lake Pollard Walk Trail car park.

Best Time to Visit the Northern Coasts of Western Australia

The northern coasts of Western Australia span an extraordinary stretch of coastline running from Kalbarri and Shark Bay in the south through the Coral Coast, Ningaloo Reef, and Exmouth, all the way north to the Pilbara and the Kimberley. This is a region of enormous geographical variety — from the Mediterranean-tinged climate of Kalbarri’s red-gorge coast to the full tropical drama of Broome and the Kimberley — and no single set of rules applies uniformly across the whole stretch. What they share, however, is a broad seasonal logic: the further north you travel, the more sharply the Wet and Dry seasons dominate; the further south, the more the climate modulates into something warmer and drier, but more manageable year-round. Understanding how each season plays across these different areas is the key to planning a well-timed journey.

🌧️ Wet Season — Summer (November to April)

Summer brings the full force of the tropics to the upper northern coasts. Across Broome, the Kimberley, and the Pilbara, temperatures regularly exceed 35°C and can climb well into the low 40s, accompanied by high humidity, monsoonal downpours, and the genuine threat of cyclones from December through to March. Many unsealed roads, including those accessing remote gorges and coastal areas, become impassable. Some resorts and tour operators in the remote Kimberley close entirely.

Further south, Kalbarri and Shark Bay feel the summer heat differently. Kalbarri sits in a warm Mediterranean climate and experiences its hottest, driest months from November through February, with temperatures regularly exceeding 35°C and occasionally touching 40°C, particularly inland and within the gorges of Kalbarri National Park. Hiking the Loop, Z-Bend Gorge, or visiting the Kalbarri Skywalk in full summer is inadvisable — gorge temperatures can be brutal and dangerous. The beach and snorkelling at Blue Holes Marine Sanctuary remain accessible, and the town maintains a lively summer holiday atmosphere during school breaks. Shark Bay is similarly hot and dry in summer, with Monkey Mia’s famous wild dolphin encounters continuing year-round regardless of season. The heat can make daytime exploration of the peninsula’s more exposed areas uncomfortable, and the Francois Peron National Park’s unsealed tracks require a high-clearance 4WD at all times.

Across the full northern coastal stretch, stinger (jellyfish) season is active from October through May, significantly restricting safe ocean swimming in many locations. Turtle nesting at Ningaloo peaks between November and February, and whale shark activity at Ningaloo can begin as early as mid-March.

What to pack: Lightweight, moisture-wicking clothing, a waterproof rain jacket or poncho, SPF 50+ sunscreen and SPF lip balm, DEET insect repellent, a wide-brimmed hat, waterproof sandals or quick-dry footwear, a dry bag for electronics, rehydration sachets, a stinger suit if swimming, and a cyclone-tracking app for travel north of Exmouth.

🍂 Dry Season — Autumn (March to May)

April and May are among the most rewarding months to visit the northern coasts, striking the ideal balance between warmth, accessibility, and wildlife spectacle. The rains ease from March onwards, humidity drops markedly, and the landscape remains lush from the wet season — particularly in the Kimberley, where waterfalls are still flowing strongly and the red-rock country is at its most vivid.

Kalbarri is at its absolute best in autumn. Locals and experienced visitors consistently cite April as the sweet spot: temperatures of 26–30°C with little wind, calm waters on the Murchison River ideal for kayaking and paddleboarding, and the gorge trails of Kalbarri National Park comfortably walkable again. Wildflowers begin their season in the surrounding countryside from around late June, but even in April the Kalbarri area offers exceptional birdlife and a noticeably relaxed, uncrowded atmosphere. Accommodation is easier to book than in peak winter, and prices are more competitive.

Shark Bay in autumn is similarly excellent. April and May bring warm, manageable days with temperatures between 24°C and 30°C, perfect for kayaking the turquoise shallows of Denham, visiting the ancient stromatolites at Hamelin Pool, and watching the bottlenose dolphins wade ashore at Monkey Mia. The seagrass beds that sustain Shark Bay’s enormous dugong population — thought to number around 10,000 individuals, the largest concentration in the world — are best explored by boat or kayak in the calm autumn conditions. Humpback whale migration passes through Shark Bay from around May as whales begin tracking northward.

Further up the coast, whale shark season at Ningaloo hits full stride from mid-March through to late July, with guided snorkel tours from Exmouth and Coral Bay filling rapidly. Booking well in advance is essential.

What to pack: Light cotton or linen clothing for warm days, a warmer layer for cool evenings, sunscreen, a hat, polarised sunglasses, reef-safe sunscreen for Ningaloo snorkelling, a rash vest or stinger suit, sturdy hiking shoes for gorge walks, a portable water supply for remote areas, and a camera with underwater housing.

❄️ Dry Season — Winter (June to August)

Winter is the undisputed peak season across the full length of the northern coast, and with good reason. From Kalbarri in the south to Broome in the north, conditions during these months are warm, reliably sunny, and almost entirely rain-free — the very definition of ideal travelling weather.

Kalbarri in winter settles into days of around 20–24°C with cool evenings and nights that can dip towards 10°C — considerably cooler than the tropical north, but perfectly comfortable for gorge walking, coastal exploration, and camping. The wildflower season, which runs from late June through October, adds extraordinary colour to the surrounding landscape. Humpback whales migrate along the coast from June through November, and spotters on Kalbarri’s clifftops regularly sight them from June onwards. The Kalbarri Skywalk — a cantilevered viewing platform extending 100 metres over the gorge — is best experienced in the comfortable winter temperatures.

Shark Bay in winter can be notably cooler than the tropical north, with daytime temperatures of around 20–25°C and nights that occasionally fall below 15°C — warmer clothing is worth packing. The Monkey Mia dolphin encounters continue daily. The World Heritage-listed area’s birdlife reaches its peak diversity in these months, with over a third of Australia’s total bird species represented in the region. Dugong boat tours from Monkey Mia and Denham operate reliably. The main concern in winter is the wind: Shark Bay can experience strong southerly winds in June and July, which makes some water activities uncomfortable and choppy.

Further north, the entire Kimberley coast, Ningaloo Reef, Exmouth, and the Pilbara are all open, accessible, and operating at full capacity. Whale sharks continue at Ningaloo into late July. Karijini National Park — one of Australia’s most dramatic gorge systems — offers cool swimming holes and comfortable hiking. Broome’s famous Cable Beach and the Kimberley’s gorge country draw large crowds in July, which is Western Australia’s main school holiday month.

What to pack: Light daytime clothing (shorts, T-shirts, light shirts), a fleece or lightweight down jacket for cool evenings and Shark Bay nights, long trousers for cooler nights and gorge walks, sturdy closed-toe walking shoes, sandals, sunscreen, polarised sunglasses, swimwear, a dry bag, binoculars for whale watching, a headtorch for gorge exploration, and any prescription medication (pharmacies are limited in remote areas).

🌸 Shoulder Season — Spring (September to November)

Spring is a tale of two halves across the northern coast. September and early October offer some of the most enjoyable travelling conditions of the year: warm but not brutal temperatures, open roads, continued wildflower displays, active wildlife, and noticeably thinning crowds following the July–August peak.

In Kalbarri, spring is the second-best period for a visit. Wildflowers are at their most spectacular throughout September and into October, with the surrounding Kalbarri National Park and the roadsides of the Midwest blanketed in everlarts, banksias, and dozens of endemic species. Whale watching from the cliffs continues until November. Temperatures climb through October, and by late October the heat begins to reassert itself; the flies also return in force. The gorge trails become increasingly uncomfortable as the month progresses, and most experienced hikers finish major walks by morning to avoid the worst of the afternoon heat.

Shark Bay in spring is lively and scenic. September through October sees warm, pleasant conditions for water activities, and the area’s turtles — green turtles and loggerhead turtles both nest in the region — begin their season from around November. Monkey Mia’s dolphins are reliably active, and dugong boat tours continue throughout. October can still be excellent, but November marks the beginning of the heat build-up that makes summer here less comfortable.

Further north, the tropical build-up arrives earlier and more aggressively. By November, humidity is rising sharply across Broome and the Kimberley, and the pre-wet-season atmosphere — known locally as “the Build-up” — can be wearing. Cyclone risk increases from November. September is the last truly ideal month for the northern Kimberley, while October is still manageable in the Pilbara and Coral Coast areas with the right preparation and heat tolerance.

What to pack: Light breathable clothing, heavy-duty SPF 50+ sunscreen, a hat, polarised sunglasses, light rain protection from October onwards, insect repellent (flies are persistent in spring), swimwear, reef-safe sunscreen, a cooling towel, electrolyte supplements, a stinger suit from November, and flexible travel insurance covering weather disruption.

🌟 Overall Best Time to Visit

For travellers covering the full sweep of the northern coast — from Kalbarri and Shark Bay through the Coral Coast and Ningaloo to the Kimberley — the window from late April through to August represents the strongest overall recommendation, with June and July standing out as the definitive sweet spot. During these months, every destination along this extraordinary coastline is open and performing at its peak: Kalbarri’s gorges are walkable and wildflower-fringed, Shark Bay’s waters are calm and its wildlife abundant, Ningaloo’s whale sharks and humpbacks are both in residence, and the remote northern reaches of the Kimberley and Karijini are fully accessible under brilliant, rain-free skies. Those who can avoid the July school holiday peak — travelling in May, June, or the first half of August — will encounter the same remarkable conditions with fewer fellow visitors, lower accommodation prices, and a little more of the vast, unhurried solitude that makes this coastline one of the finest in the world.