I have heard many a person saying that they live in a city, and will never see any fossils, or that they cannot physically get to fossil sites in the Dales as they are not able. Well, no need to worry, there is plenty to see in the city of Leeds itself. This EarthCache is suitable for the disabled, those with strollers and children. It is meant to be interesting and educational.
So what are we here to see, well first look for the limestone pillars with the golden owls on top. We are here to look for a type of fossil.
A fossil is trace or remains of a plant, animal or other organisms. However, there is more to fossilization than just bones, or remains of a T Rex.
There are many EarthCaches which can teach you about the whole process of fossilization, what we are concerned with is this certain type of fossil - Solenopora portlandica, also known as Red Algae.
What we have here is fossilised red algae. Red algae are important builders of reefs, and living examples can be seen on reefs around the world today. Coralline Algae, secrete calcium carbonate, and thus play a major role in the natural contruction of coral reefs. Over time, limestone formed as a sedimentary rock, by the accumulation of coral and sea shells.
Algae give coral reefs their colours, and also supply nutrients, whilst the coral provides shelter to the algae. A study has found evidence of this coral-algae relationship in fossilized coral dating back more than 210 million years to the late Triassic period. Some algae live inside the corals' tissues. The algae use photosynthesis to produce nutrients, many of which they pass to the corals' cells. The corals in turn emit waste products in the form of ammonium, which the algae consume as a nutrient. This relationship keeps the nutrients recycling within the coral rather than drifting away in ocean currents and can greatly increase the coral's food supply. This symbiosis helps in the construction of reefs—corals that host algae can deposit calcium carbonate, the hard skeleton that forms the reefs, up to 10 times faster than non-symbiotic corals.
So what do you need to look for, well, this type of fossil, tends to be like a bunch of flowers, or a cauliflower. It has growth lines on it, which are evdience of seasonal growth. It you look at the corner of one of the pillars you will soon see one, but you need to look closely. There is also another on one of the flat profiles of one of the pillars.
This is an earthcache. In order to log it, I ask that you answer the below questions. Please send them to me, and do not include them in your log. You can send them to me by using the message facility or email, both of which can be found by looking at my profile. Alternatively, you could also talk about your answers over a pint at one of the great monthly Leeds cachers meets - well recommended.
1. Please find the Solenopora portlandica fossil on the corner of the pillar. Please describe it length and width (at its widest aspect) in cm.
2. How many seasonal growth lines does it have?
3. Please describe its colour compared to the rest of the rock.
4. Please find the Solenopora portlandica fossil on the flat profile of the pillar - how wide is it, and now long is it (measuring along its central axis) in cm?
5. How many seasonal growth lines does it have?
6. Please compare both Solenopora portlandica fossils, which one has the narrowest gaps between its seasonal growth lines?