Droser, M., Bottjer, D.J., A semiquantitative field classification of ichnofabric. Journal of Sedimentary Petrology 56,

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1 GSA Data Repository Chemosymbiont-dominated seafloor communities in modern and Cretaceous upwelling systems support a new, high-productivity variant of standard low-oxygen models Y. Edelman-Furstenberg and S. M. Kidwell REFERENCES CITED Bailey, G.W., 1991, Organic carbon flux and development of oxygen deficiency on the modern Benguela continental shelf south of 22 S: spatial and temporal variability, in Tyson, R.V., and Pearson, T.H., eds., Modern and Ancient Continental Shelf Anoxia: Geological Society [London] Special Publication 58, p Bremner, J.M., 1978, Sediments on the continental margin off South West Africa between latitudes 17º and 25ºS [Ph.D. thesis]: Cape Town, University of Cape Town, 300 p. Droser, M., Bottjer, D.J., A semiquantitative field classification of ichnofabric. Journal of Sedimentary Petrology 56, Edelman-Furstenberg, Y., 2008, Macrobenthic community structure in a high-productivity region: Upper Campanian Mishash Formation (Israel): Palaeogeography, Palaeoclimatology, Palaeoecology, v. 261, p Edelman-Furstenberg, Y., 2014, Distribution and paleoecology of molluscan skeletal remains along an upwelling tract: Benguela system, Namibian shelf: Marine Geology, v. 353, p Kidwell, S.M., and Holland, S.M., 1991, Field description of coarse bioclastic fabrics: Palaios, v. 6, p Savrda, C.E., and Bottjer, D.J., 1991, Oxygen-related biofacies in marine strata: an overview and update, in Tyson, R.V., and Pearson, T.H., eds., Modern and Ancient Continental Shelf Anoxia: Geological Society, London, Special Publication 58, p

2 Fig. DR1. Molluscan biofacies based on cluster analysis for the (A) modern Benguela Upwelling System (BUS) on the continental shelf of Namibia, adapted from Figure 2 of Edelman-Furstenberg (2014) and (B) Cretaceous Mishash Formation (MIS), Israel, adapted from Figure 5 of Edelman-Furstenberg (2008). In each study area, biofacies were discriminated on the basis of cluster analysis of sample-level data on species abundance, using Euclidean distances (in R). The clusters here are revised slightly from those of Edelman-Furstenberg (2008, 2014) based on (i) additional faunal data about biofacies MIS-1 and (ii) including, qualitatively, samples that contained no mollusks (biofacies 0a and 0b).

3 Table DR1. A. Benguela Upwelling System (BUS) Biofaces BUS-0a BUS-1 BUS-2 BUS-3 BUS-4 Number of samples (no. 4 (0) 5 (146) 2 (199) 3 (605) 3 (477) of mollusk individuals) Shell packing density; % shells by volume (Holland and Kidwell, 1991) none Dispersed; 3 11% Dispersed; 10% Densely packed; 50 76% Shell condition NA Up to 64% are Up to 19% are Up to 3% are, up to 17% are rounded Densely packed; 61-74% Up to 1.5% are, up to 69% are rounded Richness (Margalef d) NA (zero species) Evenness (PIE) NA % pooled dominant NA 100 Lucinoma 87 Lucinoma 60 Carditella 25 Dosinia bivalve % chemosymbiont NA % deposit feeder NA % mixed feeder NA % suspension NA Body size of chemosymbiont bivalves (mm) % epifauna+epifauna/semiinfaunal (not nestlers) Gastropods (% of all mollusk individuals) TOC (wt%) (Bremner, 1978) Lithology NA Up to 45 mm No data Up to 16 mm mix of small & large NS (?mytilid) 2 (mytilid, pteriid) 6.4 (malleidae, mytilid) 0 1 (Gastropoda sp. 1) 4.5 (Gastropoda sp. 1) 5, Nassarius most abundant (carnivore/scavenger) 10, Nassarius most abundant (carnivore/scavenger) < 7 < 7 Organic-rich opal ooze, no shells Organic-rich opal ooze, some shells Moderate-organic & -opal ooze Carbonate ooze Phosphate-rich shelly debris, scant mud % opal % phosphate >20-49 % calcium carbonate >75% 22 50

4 (mud fraction) Bottom-water oxygen < 0.5 < <O 2 <1 >1 >2 (ml/l) (Bailey, 1991) Water depth (m) , 321 B. Cretaceous Mishash Formation Biofacies MIS-0a MIS-0b MIS-1 MIS-2 MIS-3 MIS-4 Number of ~10 (0) ~10 (0) 2 5-m units 8 (854) 4 (416) 8 (963) samples (no. of mollusk individuals) (no counts) Maximum shell None None Rare, loosely Dispersed Loosely packed Densely packed packing density packed patches Shell condition NA NA Diagenetic ghosts, mostly Up to 74% are ; some in life position Up to 36% are Up to 8% are, some abraded or rounded Richness NA (zero NA (zero 0 (one species , (Margalef s d) species) species) present) Evenness (PIE) NA NA NA Dominant bivalve, % abundance NA NA Lucina Mesosacella (49%), deposit feeders Mesosacella (22%), deposit feeder Caestocorbula (27%), suspension feeder % NA NA chemosymbiont % deposit feeder NA NA (Mesosacella) 16 (Mesosacella) % mixed feeder NA NA % suspension NA NA (Meretrix) 77 (Caestocorbula) Body size of chemosymbiont bivalves (mm) NA NA Up to 45 mm No data Up to 25 mm mostly small, rare large % epifauna NA NA (Nanonavis only) Gastropods (% %, dominantly of all mollusk carnivorous individuals) 5 (Nanonavis only) 8 (mostly Nanonavis,) 23%, carnivorous 15% (half Turritella, dominate half carnivorous (Undiscala) Foraminifera None Extremely None Extremely low Diverse benthic & NA (no fine matrix)

5 low diversity diversity (1-2 rare planktic spp (1-2 spp) spp) Ichnofabric Index Ichno 1 Ichno 1 Ichno 1 Ichno 1-2 Ichno 2-4 Ichno 3-4 Dominant trace None noted None noted One burrowed Some Planolites Planolites Thalassinoides layer Lithology Massive porcelanite Suggested O2 ml/l of Savdra & Bottjer, 1991; ratio = overlying water / pore water Laminated organic-rich carbonate (ORC) Massive porcelanite with rare shells Laminated ORC, thin beds of chertified micrite 0 / 0 <0.1 / 0 >0.1 <1 / 0 >0.1 <1 / localized >1 5-cm to 30-cm beds of shelly chertified micrite [we infer >1 / localized >1 Phosphate-bearing, 20- to 60cm densely packed shellbeds, scant mud >1 / extensive irrigation with >1 to some depth Table DR1. Molluscan biofacies composition and associated environmental data for (A) the modern Benguela Upwelling System (BUS) on the continental shelf of Namibia, southwestern Africa, and (B) the Cretaceous Mishash Formation (MIS), Israel, elaborating upon the biofacies recognized by cluster analysis (DR-Fig. 1). Sample-level faunal data for BUS are in Edelman-Furstenberg (2014) and for MIS are in Edelman-Furstenberg (2008). NOTES: * Margalef index D = (count of species 1) divided by log/e of N, using the entire mollusk assemblage; * Evenness PIE sum of squares of proportional abundances, ranges from 0 (dominated by a single taxon) to 1 (each species represented by same number of individuals), using the entire mollusk assemblage; * Trophic groups and % abundance are for bivalve part of assemblage only; * Body size of chemosymbiont bivalves (lucinids) = includes fragments that were at least >0.5 of specimen; * Lithology and sedimentary components of BUS from Bremner (1978), reported in Edelman-Furstenberg (2014); * Ichnofabric index of Droser & Bottjer (1986); * Shell-packing density terms of Kidwell & Holland (1991).

Feet CLAY; silty, greenish gray and clayey fine sand; Color: 5Y 3/1

Feet CLAY; silty, greenish gray and clayey fine sand; Color: 5Y 3/1 -. CLAY; silty, greenish gray and clayey fine sand; Color: Y /. -. SAND; fine-medium, clayey, with sandy clay layers; very abundant broken thin, tiny shells; shell hash at several horizons, heavily burrowed;