Pollen zone

Helianthus annuus pollen

Pollen zones are zones that can be distinguished by the different distribution of pollen at different depths of the deposits in lakes or bogs. In this way, temporal vegetation developments can be identified.

Research history

This branch of research was founded by the work of the Swedish scientists Axel Blytt (1876) and Rutger Sernander (1908). At first they only subdivided the Holocene into a proto or preheating phase, a meso or warm phase and a telocratic or post-heating phase, the so-called Blytt-Sernander sequence, based on the decomposition phases of the peat at different depths .

In the following, the research was extended into the late glacial period and refined through more precise analyzes of the pollen layers to the actual palynology and carried out separately for different areas:

In Sweden v. a. Nilsson (1935, 1964) and Lennart von Post (1944) continued to work for Denmark v. a. Knud Jessen (1935) and Johannes Iversen (1954), for the British Isles Jessen (1949) and Harry Godwin (1956), for Germany Franz Firbas (1949) and Fritz Overbeck (1975).

Heike Schneider's dissertation (2002) provides an excellent overview of German research history up to the present day.

Palynology is now used worldwide.

Working method

Using a hollow core drill, drill cores are extracted from bogs or lake deposits (sediments). These are suspended in fine layers and the pollen and mineral components they contain are isolated and counted.

meaning

For the respective study area, the palynology provides a series of statements about the vegetation and mineral inputs that allow conclusions to be drawn about the local climate (so-called climate proxies). The number of pollen diagrams available today is hardly manageable.

Palynological research makes a significant contribution to the bio- and climatostratigraphic structure of your study area, but is unsuitable for a continental or even global chronostratigraphic structure because of its spatial and temporal validity .

In addition, the pollen zones of different researchers often do not match in terms of content or time, even for comparable regions (e.g. there are different dates for Meiendorf, Elder Dryas, Bølling, or the Atlantic Ocean around 1000 (!) Years). This is due not only to the locally different conditions, but also to the various dating methods of the last few decades, which are also often insufficiently described, v. a. for quotations from other sources.

Example British Isles

Godwin (1940) found the following pollen zones for the British Isles:

Zone	Biostratigraphic subdivision	Period	dominant plant type	Archaeological period
IX	Subatlantic	500 BC to date	Extensive grasslands, pines and beech forests	from the Iron Age on
VIII	Subboreal	3000-500 BC	Mixed oak forest	Bronze Age and Iron Age
VII	Atlantic	5500-3000 BC	Mixed oak forest	Neolithic and Bronze Age
V & VI	Boreal	7700-5500 BC	Pine and birch forest	Mesolithic
IV	Preboreal	8300-7700 BC	Birch forest	late Paleolithic and early to middle Mesolithic
III	Younger dryas	8800-8300 BC	Tundra	late Paleolithic
II	Allerød-Interstadial	9800-8800 BC	Tundra and park tundra	late Paleolithic
Ic	Older dryas	10000-9800 BC	Tundra	late Paleolithic
Ib	Bølling-Interstadial	10500-10000 BC	Park tundra	late Paleolithic
Yes	Eldest dryas	13000-10500 BC	Tundra	late Paleolithic

Individual evidence

1. ^ Fritz Overbeck: Botanical-geological moor knowledge. With special consideration of the moors of northwest Germany as sources for the history of vegetation, climate and settlement. Wachholtz Verlag, Neumünster 1975, ISBN 3-529-06150-6 .
2. ↑ Heike Schneider: The late and postglacial vegetation history of the upper and middle Werra valley. Paleobotanical studies with special consideration of anthropogenic influences. Cramer in the Gebrüder-Borntraeger-Verlags-Buchhandlung, Berlin a. a. 2006, ISBN 3-443-64315-9 ( Dissertationes botanicae , 403; also: Jena, Univ., Diss., 2002).