Rationale

A prototype of this website had been originally launched during the first PAGES Varves Working Group Workshop 2010 in Estonia and displayed images of various types of varves and sedimentary components based on contributions from the “varve community”. It was the intention to show the compositional and structural diversity of varved sedimentary sequences as well as to summarize the existing knowledge about varves with images.

Although the scientific community has come to appreciate the paleoenvironmental value provided by annually laminated sediments, both marine and lacustrine, there remains a widespread lack of awareness about the need to carefully document and prove the truly varved character of laminated sediments before exploiting lamina counts for geochronological purposes and paleoenvironmental interpretations through time.

The misconception between varved versus finely laminated sediments might partially originate from the history of the expression “varve”. The term was introduced by the Swedish geologist De Geer (1912) to describe annually laminated and minerogenic proglacial lake sediments of Sweden. Later on, the term “varve” was extended to other lacustrine as well as marine sediment types with preserved annual successions and seasonal sub-laminae. The large diversity of sediments featuring a “varved” character sometimes led to the misconception that most, if not all finely laminated sediments must be varved, which is of course not always the case. It is the specific aim of this Varve Image Library to provide visual exemplary information about annually laminated sediments to assist, train and guide researchers for critically judging the relative timing of (sub)laminae and constraining the geochronological potential of newly recovered laminated sedimentary sequences. Additionally, examples of tree rings are documented, as this entirely biological natural archive is comparable with the structure of annual sedimentary laminae.

Each image is accompanied by metadata which include information about the study site, the image itself, and references with DOI links. Additionally, general information about varves as well as links to varve-related and methodologically relevant websites is provided.