Saturday is the Coring of the Cedar Creek Mastodon Site with Dr. Lowell (University of Cincinnati) and Jacklyn Rodriguez (University of Illinois). Tom Lowell truly is the Core Boss and is remarkable when it comes to extracting high quality mud from the ground.
Tom Lowell – extracting high quality mud from the bottom of a lake.
Monday we will meet with Drs. Anderson (OWU) and Goss (OARDC) at Browns Lake Bog – we will be taking a short core from around the big lake and discussing various aspects of the science of the bog. Below is a synopsis of articles (thanks Tom and Laurie) that are pertinent to the Browns Lake trip (access to the readings are on the reading page).
Sanger and Crowl 1979 – used plant pigments – It is simple property to measure, but you had better refer to the paper for what it means. The first part of the paper is a bit heavy on biological terms, but there some interesting discussion of the changes that occurred as the lake evolved. Figure 2 gives us a decent view of the general changes we should find as we core deeper into the stratigraphy.
Shane 1987 – used pollen to contrast past environmental changes at high elevations and low elevations. The pollen assemblies change over time and the assemblies (pollen zones) and they are placed in some chronological order. Such a study today would have far more detail (samples per physical level) and more ages to generate the zones. Browns lake is only one of several sites studied for this. The raw data for Brown’s lake is in Fig 2.
Lutz 2007 – is a physical description for one event in the early Holocene, the so-called 8.2-ka event. A preliminary depth map (in feet) is shown in fig 1. You can see the bottom is flat and that reflects sediment accumulating in the bottom of the basin. Note this study took 3 cores in different parts of the lake, but only a very small part of the whole core is shown in Fig 2. In one core, 3, there are two distinct silt layers that are interpreted as wind blown silt formed during dry conditions (the 8.2 event).
Shane 1993 – is a follow up of the 1987 paper by adding more sites and then applying a transfer function (calibration) to extract more quantitative estimate of temperature and precipitation. Lots of detail in this and it is a bit thick. Data from Browns Lake is included in the analysis, but it is not identified specifically. This is a general framework for climate changes over the last 18000 yr.
Glover, 2011 – takes a different approach. It also is a regional view, but for deglaciation or when the basins formed. There is only limited analysis of what happened after that. Again Browns Lake is included but it is only one of many. The take home from this paper is that the ice sheet left the Ohio region about 18,000 yr ago showing that Brown Lake is similar to other lakes.
Irleland and Booth 2012 – Described the influence of anthropogenic disturbance to bog sites and the cascading ecosystem responses. Remarkable – we can see this strongly in the short cores at BBL.