Coring and sieving

It is a tradition that on the last day of our annual third year fieldwork, we drill a core and we do geophysics. We would split up the group in two; one group does coring and the other one geophysics, and after lunch they swap. This year I was not so sure if we could do that; we had a different coring location in mind, and it was lower down in the estuary than the previous year. I feared that we could only be there during low tide. Martin, however, thought it would be fine, and I went with that. If we can't core where we want to, we can still try coring somewhere higher up!

This year we would be a lot more flexible regarding our location, as I had requested the hand coring set and not the percussion drill that we normally use. That thing with all its accoutrements is heavy! You don't want to have to carry that around. But a hand coring set weighs very little and you can walk it anywhere.

All the students would be picked up at 8:15 on the main campus, and I had decided I would go there too. I could just hop into one of the vehicles carrying the students, and that would save another vehicle having to come all the way to the field site. And I decided to drive. It would be a long and tiring day!

While I was in the car I got a phone call, so I pulled over where I could and so that was all about. It was Katrien who explained there had been a miscommunication with Dei; he would be late. She had designed a clever plan to make sure the damage would be limited. It involved everybody leaving from Menai  Bridge. That was fine with me! Gareth, one of the technicians, picked up the students that were there and ferried them to the new meeting point, while I stayed behind in order to greet the students who were still arriving. If they wouldn't find a vehicle or a member of staff they would worry! I surely would if I were one of them. And then Gareth came, and we were on our way, but the plan had already changed and we went straight to the field. We suspected we would find Dei there, but we didn't. It turned out he had direct all the students in his vehicle to where the geophysics would take place. But he had lots of students who were supposed to come coring with me! So there was a lot of confusion and standing around.

The advantage of the standing around was that we came across Martin and Guy who had just retrieved the equipment Martin always places in the field on a fieldwork like this. I hadn't seen Guy at all, because his only day in the field had been the only day where I wasn't in it! It was good to see him. And I had seen Martin, of course, but it is always nice to see his face.

When we could finally go to the coring site we did it in a clever way; Jaco has come in his own car, and that is a lot smaller than the 17-seaters the rest of us had come in, so it could negotiate the much shallower gravel road that goes all the way to the edge of the salt marsh. So we loaded all the equipment into it, and walked in comfort. We only had to carry it where the gravel road became a path.

We had brought handheld GPSs, and I had the coordinates of the core I had sunk with Martin in May. The GPSs were not precise enough to really bring us there, but that was okay; we could just sink a few trial holes. When we hit only sand we decided to go further down towards the centre of the estuary; it was not too long after low tide, and we knew there were interesting sediments outcropping there. And we managed to core up something interesting!

The suspected fossil saltmarsh layer add guided us

Sediments description

I had requested a second person for the coring, and Jaco had got that task. And he loves his sediments! So basically, once we started coring for real (so no test core this time) I stepped back and let him take charge of the sediment description. He is good with that! I was mainly interested in taking samples of all the various sediment horizons we got. And with his eye for detail, we got quite a number, but I'd rather have too many than too few. 

We cored down to about 80 cm, and then it was almost time to pack up. We decided to briefly try out two new gauges and augers we had, but then we gathered everything and went back to the car. Time for lunch! And then doing the same with a new group.

We went to the main car park, where there are picnic benches, public toilets, and an ice cream van. And the geophysics group. By that time I was ravenous!

After lunch we took the new group to the same site. This time we decided to stay a bit higher up. It was much closer to high tide, but the water was not worryingly high. But there is nothing wrong with being a bit higher up! We managed again to core up something interesting. We described it and sampled it, and took the coordinates. But then it was time to go home!

The second core site

We drove back to Menai Bridge, and there unloaded what needed unloading. And from there we went to Bangor. When we all got out of the vehicle it was the end of the fieldwork proper!

The only thing left to do was a session in the lab the next day. The students have to hand in their field notebooks, but they need a little bit of time to process all they had done all the last day. And with this session in the lab there would be staff they could ask questions, and there would be IT facilities. I thought it was a good idea. Martin had given me the day off; not all staff needed to be there to answer questions. But I had such a big load of core samples I decided to come anyway. I wanted to get the sample processing over with! And it would be the most sociable morning in the lab ever. And Martin would provide coffee and biscuits!

When I got there, I started sieving. The samples each wouldn't take much time; most of it was sand. But there were many of them! I had made the right call, though; there was a good atmosphere in the lab. And I saw the students around me put the finishing touches on their rather good-looking notebooks. It would be a pleasure to mark that!

There was one student who had come by car, and had offered a lift to as many students as it would hold. When she was done she looked a bit bored. She couldn’t leave until her passengers were done too! I saw an opportunity, and ask her if she was willing to give me a hand with the sieving. I had taught them exactly how to do it earlier in the week! And she was so kind. And then one of her passengers was finished too, and he also joined in. This meant that when the session came to an end, all the sieving was done! That pleased me.

When the students were done, Katrien, Martin and I tidied up. Time to go home! Now the fieldwork was truly over. I think the whole trip has been a success. Of course there were things that could have been done better, and we will have a meeting about it, but I went home satisfied! And not anywhere near as stressed as I was last year. We'll see how the students do in the rest of the module; they have some data to create and/or work up, including some foram analysis to do. All of that goes into the final assessment. I hope they get it, and that they will do well! And that this will be a good memory for them forever. I would say it is for me!