🪨 PLANT FOSSILS: READING DEEP TIME
PAGE 1 OF 5, PLANTS FROZEN IN STONE
ROCKS REMEMBER
PLANTS THAT BECAME ROCK
Long before humans existed, forests grew, leaves fell, and pollen drifted on the wind. Most rotted away. But some were buried fast enough to survive as fossils. Today those stone plants let scientists read Earth's history like a giant diary written in rock. A single fossil leaf can reveal what a forest looked like millions of years ago.
⚡ DID YOU KNOW?
The word "fossil" comes from a Latin word meaning "dug up." Every plant fossil was once a living organism that got buried before it could decay.
DEEP TIME!
PALEOBOTANY
🔬 Paleobotany = study of ancient plants
📖 Fossils are nature's history books
📖 Fossils are nature's history books
DEEP TIME
⏳ Some plant fossils are 400+ million years old
🌍 They span almost all of land plant history
🌍 They span almost all of land plant history
PAGE 2 OF 5, HOW PLANT FOSSILS FORM
BURIED BEFORE DECAY
FOUR MAIN FOSSIL TYPES
Plant fossils form in different ways. Compression fossils flatten leaves between layers of mud that harden into shale. Petrified wood swaps organic tissue for minerals like silica, turning trunks to stone. Pollen and spores, tiny but tough, survive in sediments and ice. Coal itself is compressed ancient plant matter from Carboniferous swamp forests. Each type tells a different part of the story.
PRESERVED!
COMPRESSION
🍃 Flat leaf prints in shale
🪨 Mud layers squeeze plant remains
🪨 Mud layers squeeze plant remains
PETRIFICATION
🪨 Minerals replace wood cell by cell
🌈 Iron makes rainbow stone colours
🌈 Iron makes rainbow stone colours
MICROFOSSILS
🌼 Pollen grains survive for ages
🔬 Each species has a unique shape
🔬 Each species has a unique shape
PAGE 3 OF 5, PETRIFIED FORESTS
SILICA SWAP
💎 Dissolved silica seeps into buried logs
🪨 Organic wood slowly becomes quartz
🪨 Organic wood slowly becomes quartz
ARIZONA'S STONE TREES
🌲 Logs over 30 metres long preserved
🦕 From the age when dinosaurs walked
🦕 From the age when dinosaurs walked
PETRIFIED FOREST
WHEN WOOD TURNS TO CRYSTAL
About 220 million years ago, Triassic trees fell into river channels in what is now Arizona. Volcanic ash and mud buried them quickly, cutting off oxygen. Over thousands of years, silica-rich water soaked into the wood and crystallised inside every cell. Today Petrified Forest National Park holds one of the world's greatest collections of rainbow-coloured stone logs. You can still see tree rings in the rock!
STONE!
PAGE 4 OF 5, POLLEN, LEAVES & CLIMATE
CLIMATE DETECTIVES
FOSSILS REVEAL ANCIENT WEATHER
Scientists use plant fossils as climate clues. Fossil pollen buried in lake mud and ice cores shows which plants grew nearby, and each species prefers certain temperatures and rainfall. Fossil leaves from about 50 million years ago reveal warm, wet forests where polar regions are icy today. At the K-Pg boundary about 66 million years ago, pollen records show ferns exploding after the asteroid impact wiped out many trees. Plant fossils track mass extinctions and migrations across continents.
CLUES!
POLLEN POWER
🧊 Pollen trapped in ice cores & lake beds
🌡️ Species mix reveals past climate
🌡️ Species mix reveals past climate
LEAF IMPRESSIONS
🍃 Leaf shape hints at rainfall levels
🌴 Smooth edges often mean warm climates
🌴 Smooth edges often mean warm climates
EXTINCTION LAYERS
☄️ K-Pg layer marks dinosaur extinction
🌿 Fern spike shows forests recovering
🌿 Fern spike shows forests recovering
PAGE 5 OF 5, READING EARTH'S DIARY
FOSSILS STILL MATTER
PLANTS WROTE EARTH'S STORY IN ROCK
From Devonian mosses to Triassic stone trees, plant fossils map how life responded to a changing planet. They show when forests spread, when climates warmed or cooled, and when catastrophes reshaped whole ecosystems. Scientists compare ancient plant communities to modern ones to predict how today's forests might react to future change. Every fossil is a message from a world that no longer exists.
🎓 GENIUS MOMENT
The Wollemi pine was known only from fossils until living trees were found in Australia in 1994. Sometimes fossils help us recognise plants we thought were gone forever!
HISTORY!
WHAT FOSSILS TEACH
🌍 Past climate & plant migrations
☄️ Mass extinction recovery patterns
☄️ Mass extinction recovery patterns
REMEMBER
🌱 KEY FACTS
🪨 Compression, petrification & pollen fossils
🌲 Petrified Forest logs: ~220 million years old
🧊 Pollen in ice cores tracks ancient vegetation
🍃 Leaf fossils reveal past temperature & rainfall
📖 Plant fossils = Earth's climate diary in stone!
🧠 QUIZ TIME!
PLANT FOSSILS · 5 QUESTIONS
QUESTION 01
What happens during petrification of wood?
QUESTION 02
Why is fossil pollen so useful to scientists?
QUESTION 03
About how old are the petrified logs at Petrified Forest National Park?
QUESTION 04
How do compression fossils on shale usually form?
QUESTION 05
What can scientists learn from ancient leaf fossils?
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