The Basilisk: a creature so powerful that staring directly into its eyes can cause instant death. Look at it through a reflection or a lens, and you will be petrified. First introduced in Harry Potter and the Chamber of Secrets, the power of this creature is one to be feared. Rumour has it that it has been around the Magic Forest, lurking in the darkness and petrifying unsuspecting creatures. This cache brings you back into the Forest, where you can see relics of this creature’s power!
The Earthcache
The Basilisk’s powers may be unimaginably scary, but did you know that Mother Nature herself, too, has the awesome powers of turning living creatures into stone! At the published coordinates, you will find specimens which show how trees can be transformed into stones, as we explore the phenomenon of “petrified wood”
What is petrified wood?
“Petrified” is derived from the Greek word “Petros” meaning “stone” and petrified wood is basically fossilised wood: wood that has literally turned completely into stone. Do not be fooled by the stones’ looks: petrified wood look like trees, are shaped like trees but are 100% NOT wood.
How are they formed?
Many, many years ago, these stones were really what you might expect them to be: perfectly good living trees. But, some catastrophic event, like a volcanic eruption or a flood caused the trees to be buried in ashes or mud extremely quickly. Such a swift process means that the wood had no time to be broken down by bacteria or fungi on the surface, and thus, becomes preserved and locked in the form it had when it was buried. This is further bolstered by the oxygen-poor conditions of the ground itself, meaning that most bacteria and organisms that consume organic matter cannot thrive, slowing down its decomposition dramatically.
Over time, mineral-rich water in the soil seeps into the organic cells of the wood filling up the gaps in between. When the water evaporates, the minerals themselves get left behind and these minerals slowly replaces the content of the cells with harder substances and crystals like quartz or calcite. The minerals imitate their moulds so completely that they look just like the wood itself. Over the centuries, all the organic matter is slowly broken down, but the more resilient stuff, which is the minerals that have seeped and solidified in the cells, remain behind. The result is stone that looks exactly like the wood that it was formed in, just like how the jelly looks exactly like the mould it was left to cool in.
What do they look like?
The minerals that from the petrified wood are usually quartz and calcite which are normally colourless, but the actually wood themselves take on colours based on the elemental and mineral content of the surrounding earth. The following lists the common minerals and colours that they provide the petrified wood:
• carbon – black
• cobalt – green/blue
• chromium – green/blue
• copper – green/blue
• iron oxides – red, brown, and yellow
• manganese – pink/orange
• manganese oxides – blackish/yellow
Petrified wood is found all over the world where the conditions are right for the transformation from wood to stone. There have been no specimens of such stones found in Singapore to date, so the Earthcache site provides locals an opportunity to observe some of these stones up close. Petrified wood tell the story how the plants and climate of ages past, and these stones, too, tell a story of the ecology and climate of our region.
Where did these petrified wood come from?
As mentioned, Singapore lacks deposits of petrified wood, but one of our neighbouring countries have these beautiful stones in abundance. The wood you see at the site come from the Indonesian islands of Java and Sumatra and date to the Neogene geological Period (3 - 23 million years ago), found buried most often in a layer of tuff (which provides a huge clue on how they came to be buried). The climate of the islands during this period was very much like today: hot and humid tropical climate with plenty of rainfall. This was ideal for the growth of huge tracts of dense rain forests on the islands. The abundance of trees, coupled with certain conditions and natural phenomena were ideal for the creation of these petrified wood during the Neogene period. To date, thousands of tonnes of deposits of these wood have been uncovered in Indonesia.
The petrified wood you see at the site were created from the dominant family of hardwood trees in Southeast Asia, the Dipterocarpaceae. These family of trees still exist in our rain forest today, and so these wood were moulds of the ancestors of the flora that we can still see today. These show that climate in the region was not very different from that millions of years ago, and that the rain forests of the region already existed. It's truly beautiful how these stones can give us a biological window into the past
The Earthcache site
At the coordinates, you will find a set of petrified wood “trees” related to the tasks for this Earthcache. You will need to complete the following tasks to complete the Earthcache
- Describe the shape, colour and texture of the petrified wood at the coordinates. What are the different colours that are present on the wood? Where are these colours on the surface of the wood? Describe the features of the original trees that can still be seen on the petrified wood today
- Suggest the identities of the minerals present in the location where the wood were buried based on the colour of the wood.
- Based on the area of origin of the petrified wood at the coordinates (i.e. Indonesia), suggest how the wood that was to become petrified were quickly buried. In addition, why were the conditions in the Indonesian forests so ideal for the petrification of these wood?
You can log the cache once you send us the e-mail with the answers. There is no need to wait for a reply. We will let you know if there are any issues.
Feel free to post your pictures of your visit to the Magic Forest in your logs, but, PLEASE, no photos that will give away the answers to the tasks.