Barite
Ribbed minerals
There were giant life forms on Earth.
Why not giant life forms on Mars?
Crinoid Stem fossil
Above is a piece of a nicely cleaned and preserved stem of an ancient crinoid
animal. These creatures have lived in Earth's seas since time out of mind.
Today there are only a few types of crinoids left. But who knows, with all the deep-sea
exploration (and discoveries) going on, maybe there are more than we suppose.
Other names for crinoids are
sea lilies or
stone lilies. But they are
not plants. This animal belongs to the phylum, Echinodermata, which includes such
things as the starfish and sea cucumber. All echinoderms have tube feet. Tube feet are
highly sensitive appendages connected to the water-vascular system, and depending
on the creature they belong to, aid in feeding, respiration and transportation.
Below is my drawing of a rather stylized crinoid. But it represents all the
basic parts. The calyx contains most of the vital organs. The arms extend out from
the head of the calyx. Tube feet, food grooves, pinnules and/or cilia located along the
arms bring food down to the mouth in the upper head. The stem supports the calyx and
the roots hold it to the sea floor, a rock or some other object. Some modern crinoids
are free swimming as adults. The cirri on the stem (exaggerated in the drawing) form an organelle made of cilia, small
hair-like appendages that add in feeding or movement.
The stem is the most interesting part of this animal.
The crinoid stem is composed of many calcareous disc-like segments, called columnals.
They are quite flexible, and when the animal dies the columnals often fall apart.
Crinoid discs are one of the Earth's most plentiful fossils, but the calyxes and softer parts
are not so well preserved. Crinoids live together.
This is why large populations of crinoid fossils are found in the same place. For
instance crinoidal limestone got its name because of the large number of crinoids
in it. Could this be the case on Mars? Is this why these "tubes" seem to come in
groups?
Larger Image -- Good Detail
This is one of my favorite rocks. I recommend clicking on the link to see all the
effects of the larger image.
A: In the upper right you can see part of
the head is preserved. These are the calcareous plates that cover and protect the
soft body parts in the calyx.
B: In the lower left it looks like the arms.
There are all kinds of crinoid parts in this rock, but I cannot say for
certain what they are.
C points to a
stem; the segments are together. It is easy to find the stems. But beware! The eye
can fool you.
C is pointing to a fossil that is actually there.
Right below it, where
D points there is no crinoid disc - only
the impression of the disc remains. In other words it is concave. But it shows up
rounded in the scan.
E points to a fossil that is
actually there, quite rounded, but my eyes fool me. In this small image it is rounded,
convex. In the larger image I see it as quite concave - inverted. I have a hard time
tricking my eyes back to convex, even though I KNOW the fossil is sticking out of the
actual rock that sits front me.
So, what are we really looking at when we view images from Mars?
Answer: We don't know for sure.
The other side of the rock has many "tubes".
Larger View
Crinoid Discs.
Larger, Clearer View
You can see some discs are still connected and some are not.
Closeup - Crinoid Discs.
Larger View
Watch out for the inversion factor.
Fingers for Scale
You can see that these stems are small. But what is to stop such a life form from
developing as the dinosaurs did on Earth? Some dinosaurs were as small as a chicken,
and some were as large as a building. What is to stop another planet, in our own solar
system, from developing life and loosing life in a similar fashion?
Comparing the Crinoids to the Martian "Tubes"
The tube structures follow the path of the fissures. Crinoid fossils are in jumbled groups.
Crinoid discs often break up. The ribs of the tubes seem to stay together. However,
some tubes look strangely out of place, as in this example on
page 2 of this essay.
