Monday, September 21, 2009

Beachcombing: Sand Through My Fingers

To see a world in a grain of sand,
And a heaven in a wild flower,
Hold infinity in the palm of your hand,
And eternity in an hour.
William Blake - Auguries of Innocence

I’ve written about Beverly & Greg becoming psammophiles or sand collectors. The word psammophile can also be used to describe an animal that prefers to live in the sand ("sand loving"). I am sure that my two friends are truly missing the warm sandy beaches of Saipan so it is not too far fetched to call them as such. I’ve been collecting small samples of sand to send the two every time I beachcomb. So far I’ve about 13 samples and only missing samples from a few beaches on Saipan. Take a look at some of the samples:


Hidden Beach is the northernmost Eastern beach on Saipan located in the village of Talofofo. It is a small pocket of a beach at the end of a stream. Most of the sand is composed of broken corals and shells.


DJ, TonTon & Laurina at San Juan Beach.

San Juan Beach is the most immediate beach south of Hidden Beach but the composition of the sand is quite different.

Look at it closely and you can see sizable silica crystals. Silicate rocks (SiO2, Silicon dioxide) like Quartz and Citrine, and carbonates like Calcite and Aragonite (CaCO3, Calcium carbonate) are quite abundant here to the delight of crystal hunters.

Black sand beaches on Saipan? Sure! I found a patch of black sand at LauLau Beach, Kagman close to where the dive cut is at. I’ve had the samples for more than 3 years thinking that they were mica (aluminum silicate). Mica usually forms in flakes but looking closely at the samples, the grains are clearly many sided.

I was using a dental scraper and noticed black sand grains clinging to the metallic tool! The sand was magnetic! The black sand in LauLau is magnetite after all: an iron oxide (FeFeO4). Magnetite is 72% iron and geologists have used their natural characteristic to align themselves to the North Pole to figure out the past movement of continents. This technique is called paleomagnetism.

There are also lots of silica crystals mixed in the Lau Lau sample as well. Sifting allows the lighter crystals to move to the top while the heavier magnetite to settle at the bottom.
Oooh! Crystals!
Some Japanese islands are famous for their star sand and are marketed to the tourists that way. I noticed a star sand bloom a few weeks ago at Ladder Beach. Star sand are single-celled marine protozoans called foramineferans (forams for short). I often hear that there are more star sand at Long Beach, Tinian but I now believe that they are more common than we think on Saipan (I’ve seen them all over). All you need is a scrutinizing eye for their beige colored tests! Can you see the star sand? Look closer...

I'm pretty sure Bev & Greg will have nicer pics to share from their Leica cam!

Go to Marpi Village, pass the landfill and follow the unpaved trail to Cow Town Beach. Here are my buddies Kevin & DJ from a few months ago. At low tide, you will see a patch beach that is full of star sand, broken corals, micro shells, and Marginopora to the left of the entrance.
I like to call the Marginopora, halo sand because of their disk shape. Marginopora like star sand are forams. Can you see the halo sand?
Here they are...
Okay! If all that talk about sand was boring to you, here is a cute picture of Hayden Lucas to make up. He is becoming quite a beachcomber and psammophile himself!

I picked up a pretty crab head of what looks like a Carpilius convexus (Forskal, 1775) also known as the Variable Coral Crab. It belongs to the Xanthidae Family also known as the Coral crabs or Dark-fingered crabs.
Many Xanthids are poisonous. Sadly, I hear that they are eaten in some Micronesian islands to commit suicide.

I was surprised to see starfish in the shallow Saipan Lagoon. When I first saw one, I thought it accidental or misplaced. Then I found more. These are Linckia multifora (Lamark, 1816) or Spotted Linckia seastars. I often find them living in coral reefs rather than on sandy lagoons with sea grass. They are related to the much bigger and better known Blue Sea Star, Linckia laevigata (L, 1758). These stars have the habit of discarding an arm that often regenerates into a whole new sea star! Of course, we returned these animals to their respective spots unharmed with all their arms still intact.
Well, that was just a little story I wanted to share before I go to bed. I hope you enjoyed it and lets talk stories again soon. Take care and stay safe.

Ti napu.

The Beachcomber


Sean said...

Not boring at all! I'll be linking to this blog when my science class gets into geology/earth science.

I loved this perspective on familiar beaches. Kinda makes me want to start collecting sand too!

Forgotten said...

This is COOL! My class would love this!

Anonymous said...

Proud to say we are lucky to be involve in your hobbies. Enjoyed every moment spent. You're one great teacher, and very influential to DJ and other kids that share what you love doing most. Thanks for sharing your knowledge...

Bev said...

Oh so excited about the sand samples! Miss ya!

Deece said...

This is very cool! I never paid much attention to sand - but I think I will now.

Anonymous said...

Check out this article:

Glad to know that I do not need to go to Tinian's Chulu Beach to find star sand now that I've read your post!