Publication Date:
2021-03-29
Description:
Our paper (Arp et al. 2003) revises previous studies of Kaz´mierczak and
Kempe (1990, 1992), Kempe and Kaz´mierczak (1990a, 1990b, 1993), and
Kempe et al. (1996, 1997) on Lake Satonda reefs with regard to biofilm
calcification and microbialite formation. We confirm that the transfer of
bottom waters of increased alkalinity (due to sulfate reduction) to shallow
water layers (mixolimnion) principally can support or cause biofilm calcification
and microbialite formation in shallow waters (as suggested by
Kempe 1990). However, their two-stage model of microbialite formation
in Lake Satonda, which claims that superficial in vivo permineralization of
coccoid cyanobacterial colonies by high-Mg calcite is followed by internal
fibrous aragonite growth due to anaerobic decay of the entombed colonies
to form microstromatolites (Kaz´mierczak and Kempe 1990) as well as
Wetheredella-like structures (Kaz´mierczak and Kempe 1992) is a theoretical
construct without supporting evidence from data and observations from
Satonda crater lake. Also, the comparison of Lake Satonda stromatolitelike
encrustations on green algae with early Paleozoic stromatoporoids by
Kaz´mierczak and Kempe (1990) lacks—in our opinion—any supporting
evidence.
In their discussion, Kaz´mierczak and Kempe reiterate allegations seemingly
supported by images and data. At a closer look, results obtained from
inadequately treated samples (air drying, etching fractures, or cutting
planes), a tendentious identification of coccoid structures, analytical failures
(basic mineralogy from EDX measurements), and biased consideration of
data (supersaturation) results in theoretical misconceptions of post-mortem
calcification of degrading cyanobacterial colonies. Our positions and arguments
follow.
Keywords:
Paläontologie: Allgemeines
;
551
;
VU 000
;
38.20
;
38.2
Language:
English
Type:
article
,
publishedVersion
Format:
application/pdf
