Figure 1.
A, B. Peregrinella multicarinata (Lamarck, 1819) from Rottier, southeastern France (EM 36190). C. Field image showing the mass occurrence of Peregrinella whitneyi (Gabb, 1866) at the Wilbur Springs seep site in California, USA.
Figure 2.
Distribution of the Peregrinella occurrences discussed herein, plotted on a paleogeographic map of the late Berriasian (140 m.y.a., [98]).
Gray stars indicate occurrences for which new data are available: 1, Bonanaza Creek, Alaska; 2, Rice Valley and Wilbur Springs, California; 3, Incoronata, Italy; 4, Châtillon-en-Dois, Curnier and Rottier, southern France; 5, Musenalp, Switzerland; 6, Raciborsko, Poland; 7, Zizin Valley, Romania; 8, Planerskoje, Crimean peninsula. White stars indicate occurrences known from the literature: 9, Guanajuato seamount, Mexico; 10, Bohrung Werle, northern Germany; 11, Kuban, Russia; 12, Xainza County, Tibet.
Figure 3.
SEM images of well preserved Peregrinella shells with unaltered shell microstructure.
The examples are from: A: Incoronata (GZG.INV.82745); B: Planerskoje (GZG.INV.82739); C: Musenalp (GZG.INV.82737); D: Curnier (FSL 425078).
Table 1.
Sr-isotope data and possible stratigraphic ages derived from the LOWESS 5.0 curve [52].
Figure 4.
Strontium isotope curve for the Early Cretaceous and its upper and lower confidence interval [52].
Dashed lines indicate our measurements on Peregrinella shells; shaded areas indicate the error margins (vertical: Sr isotope ratio; horizontal: geologic age) of those ages that fall within the biostratigraphically possible age range.
Figure 5.
Petrography of Peregrinella limestones.
Images are ordered by an increasing proportion of seep cements (light colored), compared to microcrystalline carbonate (micrite; dark colored). A: Incoronata (GZG.INV.82754); B: Musenalp (GZG.INV.82734); C: Rottier (FSL 425077); D: Curnier (GZG.INV.82728); E: Rice Valley (GZG.INV.82748); F: Wilbur Springs (GZG.INV.82753); G: Bonanza Creek (USNM 603602), H: Raciborsko (ZPAL Bp.III).
Figure 6.
Carbon and oxygen isotope values of Peregrinella-bearing limestones.
All values are reported relative to the PDB standard. * Data from [99].
Table 2.
Summary of ecologic and environmental characteristics of Peregrinella-bearing localities, compiled from our own data and the literature.
Table 3.
Summary of the stable carbon and oxygen isotope data.
Figure 7.
Hydrocarbon fractions (total ion currents) of the Curnier and Musenalp limestones with Peregrinella.
Circles: n-alkanes; white triangles: regular isoprenoids; black triangles: irregular isoprenoids; Pr: pristane; Ph: phytane; PMI: pentamethylicosane; istd.: internal standard; UCM: unresolved complex mixture; compound-specific δ13C values are indicated in per mil relative to the Peedee belemnite standard.
Table 4.
Peregrinella and chemosymbiotic bivalves at Cretaceous seep deposits.
Figure 8.
Shell sizes of chemosymbiotic bivalves at late Mesozoic methane seeps.
Figure 9.
Geologic ranges of seep-inhabiting mollusk genera and Peregrinella during the Late Jurassic – Early Cretaceous.
Data from [8], [25], [30], [41], [61], [67], [74], [100], [101]; absolute ages from [64].
Table 5.
Numbers of species at seep deposits from the Peregrinella interval; a = absent, p = present.
Figure 10.
Paleotemperatures derived from δ18O values of Peregrinella shells.
Localities ordered from oldest (left) to youngest (right).