A new method of rock disintegration and foraminiferal extraction with the use of liquid nitrogen [LN2]. Do conventional methods lead to biased paleoecological and paleoenviromental interpretations?

Abstract

An extremely fast, easy, and clean method of rock disintegration and foraminifera extraction from variously lithified porous rocks with the use of liquid nitrogen [LN 2 ] is proposed. This method markedly limits the time of rock disintegration from days to only minutes, is safe for foraminifera, and does not require special chemical labs. In the experiment, the LN 2 method was used to decompose rock samples and simultaneously to extract the foraminifera hidden within. The proposed method disintegrates the rocks to a finer fraction than conventional methods such as the Glauber's Salt method, allowing to collect more smaller planktonic and benthic foraminifera, resulting in marked changes in foraminiferal assemblages e.g., the planktonic/benthic ratio [P/B defined as P/P+B], leading to new conclusions. The comparison between the LN 2 and Glauber's Salt [GS] methods and obtained results are provided. ► Fast and easy microfossil extraction with use of liquid nitrogen is proposed. ► The time needed for rock disintegration is limited from days to only minutes. ► The new method gives more reliable results e.g. P/B ratio. ► New perspectives and possibilities in paleoenvironmental interpretations. ► The method seems to be applicable for variously lithified porous rocks.