There are times when you are going about your daily routine, enjoying life, and suddenly a thought appears! For instance, “I wonder how deep the sand on the beach is.” So, for the interest of curiosity, read on as we answer the question.
Beach sand depth can vary from location to location. Sand can reach a depth of as little as a few inches to as many as tens of meters deep. However, the volume of sand on a beach does not stay consistent. The amount of sand found on a beach can change with every season, storm, and wave.
So, now that we know that the depth of sand can vary, what is underneath all that sand? Read on to find out exactly that and how beach sand is formed.
How Deep Is Beach Sand?
This is a difficult question to address because there is no clear-cut answer. Because the depth of the beach sand varies significantly, the answers to this question for some beaches do not even nearly resemble one other. So what typically is the average depth of beach sand? One can’t say.
Beaches around the world differ significantly, and so does the depth of the sand. The surrounding geology is a huge factor in how much sand might be present on the beach. For instance, some beaches have sand that goes a depth of as little as a few inches (you can commonly find shallow sand like this at rocky beaches).
On the other hand, some beaches have a sand depth that reaches tens of meters deep. What makes it harder to determine a specific number is the amount of sand on a beach can change with every season, storm, or wave.
To give you an idea of how much sand on the beach can change, here is an example: after Hurricane Sandy in 2014, 3.5 million cub yards of sand was used in an attempt to restore the beaches in Queens. Approximately three years later, as of 2017, the ocean had eaten its way to the dunes and boardwalk in some areas.
Whether the huge shift in sand volume is due to the sand’s artificial placement on the beach is debatable. However, the primary takeaway is to be aware of the ocean’s and other forces’ ability to alter the amount of sand on a beach at any given moment.
What Is Underneath The Sand At The Beach?
Various things may lie beneath the sand on the beach. And like the answer for ‘how deep is the sand at the beach, this too is not a one-size-fits-all answer. What is underneath the sand is mainly determined by the geological location. But before we go more into that, let’s first distinguish the sand you may find at the beach.
Loose sand covers the surface of the beach, and at some beaches, the amount of loose sand is greater than others. However, underneath the loose sand, you will often find a hard, compacted layer of sand. With enough time, and the right conditions, such as the necessary cement, heat, and pressure, this sand can turn into sandstone.
Other beaches may find a myriad of sedimentary rock, bedrock, and limestone underneath the sand. If the beach is in a geologically active area, you may discover volcanic sediments and igneous rocks like granite underneath the beach sand.
What is below the beach sand varies in every part of the world to varying degrees. However, if you take into consideration the surrounding geological area, it may give you some insight into what lies beneath beach sand.
What Is Beach Sand Made From?
How beach sand is formed is, without a doubt, an intriguing process.
Each beach’s sand is unique, like a fingerprint, and is formed due to specific characteristics unique to that beach, such as the surrounding geography, weather, and so on.
One of the main contributors to beach sand is from rocks on the land. Over time, the elements erode the rocks into smaller and smaller pieces until you eventually get what would resemble beach sand.
The waves and tides also help make the smaller pebbles and rocks into sand by knocking them together, which eventually wears them down. If this happens enough, and for a long enough period, the grains will become smaller and rounder, making the sand softer and more smooth.
This is one of the reasons why some beach sand feels rough and abrasive while others feel like the epitome of paradise beach sand. However, not all beach sand is a result of this erosion process.
Some beach’s get their sand from entirely different sources. Some beaches get their sand from the ocean, such as from seashells, other marine organisms, or coral reefs. Over time, the waves have pounded these organisms together, resulting in beach sand. On the other hand, some beaches derive their sand from volcanic material.
Interestingly, this can cause the beach sand to change to unusual colors, such as the black sand found on beaches in the Hawaiian islands. There is also red and green colored beach sand found on beaches around the world.
Red beaches can be due to a rich presence of iron derived from volcanic rock, while black beaches are made from obsidian or volcanic glass. Also, green beaches result from a high presence of the mineral olivine in the sand.
It may be interesting to note that most of the sand on the world’s beaches comprises of the minerals quartz and feldspar. These minerals are more resistant and take long to erode than other minerals.
Conclusion
Sand varies in depth all over the word. Some beaches have minimal sand, while other beaches have a sand depth of tens of meters. What can be found underneath the sand varies too. The geologic environment and exposure to the elements over many, many years help to create the beaches we know and love today.
Overall, each beach is distinct, leaving us with a unique imprint of its history. So the next time you go to the beach, think about how long it took to create this remarkable and often overlooked part of mother nature.
References
- https://www.whoi.edu/know-your-ocean/did-you-know/how-is-beach-sand-created/
- https://www.nytimes.com/2017/12/15/science/beaches-sand-erosion.html
- https://www.scienceabc.com/nature/why-is-there-sand-on-beaches.html
