Site 1214 yielded sediments of Neogene to Hauterivian age. The Neogene section consisted of a thin veneer of upper Pleistocene foraminiferal sands. A major unconformity separates this layer from underlying upper Albian sedimentary rocks. These sedimentary rocks primarily consist of cherts, with occasional layers of limestone and porcellanite. Sedimentation rates were relatively high throughout the Albian and Aptian. Nannofossil and radiolarian biostratigraphy suggests that at least the upper to middle portion of OAE1a was recovered in Core 198-1214A-23R. Below this interval, sediment accumulation rates decrease in the Barremian and Hauterivian.
Calcareous nannofossils are generally abundant and moderately preserved in Hole 1214A. Planktonic foraminifers are poorly preserved in both the Neogene and Cretaceous samples and few in number in the Cretaceous. Samples in the Cretaceous were commonly scraped from ooze or chalk on chert pieces.
Studies of benthic foraminifers were conducted on a few samples from Hole 1214A. They are common and well preserved in the Neogene but are poorly preserved and exhibit low abundances in the Cretaceous section. Stratigraphic ranges of benthic foraminifers are summarized in Table T3.
Radiolarians were examined from only one sample (Sample 198-1214A-23R-1, 47-49 cm) and are generally well preserved.
Calcareous nannofossils are generally abundant and moderately to well preserved throughout the section in Hole 1214A (Table T4). The section comprises a single core of upper Pleistocene overlying an Albian to Hauterivian sequence that is missing most or all of the Barremian. With the exception of the Pleistocene core, recovery was limited to chert pieces, porcellanite, and small pieces of chalk, and most nannofossil samples were scraped from the soft ooze/chalk on chert pieces. Almost all favorable lithologies were sampled, and all cores yielded nannofossils.
The Pleistocene is represented only in Section 198-1214A-1R-CC and contains Pseudoemiliania lacunosa and Gephyrocapsa parallela, indicating Subzone CN14a.
The Cretaceous section ranges from the upper Albian (lower Subzone NC10a) to Hauterivian (Zone NC4). The uppermost Cretaceous sample (Sample 198-1214A-2R-CC) contains Eiffellithus turriseiffelii and Staurolithites glaber, indicating the lower part of upper Albian Subzone NC10a. A condensed section or unconformity may exist in the middle Albian, as suggested by the co-occurrence of the FOs of E. turriseiffelii, Eiffellithus monechiae, and Tranolithus orionatus. With that exception, the Albian section is biostratrigraphically complete.
An organic-rich and noncalcareous interval was recovered toward the base of the Aptian section in Core 198-1214A-23R, and nannofossil biostratigraphy suggests that this correlates to Zone NC6, which supports the correlation of this interval with OAE1a. The green porcellanites and claystones were barren of nannofossils, but a siliceous limestone piece at the bottom of the core (Sample 198-1214A-23R-1, 120-122 cm) yields the lowest downhole occurrence (i.e., FO) of Hayesites irregularis, marking the base of Zone NC6 (lower Aptian). The core below, Core 198-1214A-24R, contains Cruciellipsis cuvillieri and Calcicalathina oblongata, indicating Hauterivan Zone NC4. Samples from Core 198-1214A-24R also contain very abundant Micrantholithus fragments and rare nannoconids and present something of a paleoecological/paleobiogeographic conundrum, as these taxa have not been recorded from stratigraphically comparable sediments recovered at Site 1213.
The sequence cored in Hole 1214A comprises a single core of upper Pleistocene sediments overlying a Lower Cretaceous sequence. The planktonic foraminifers in the Pleistocene sample (Sample 198-1214A-1R-CC) are poorly preserved and are characterized by selective dissolution and fragmentation (Table T5). The assemblage is dominated by Globorotalia inflata and Truncorotalia crassaformis. This sample is assigned to Zone N22 based on the presence of few Truncorotalia truncatulinoides and Truncorotalia tosaensis.
In the underlying Lower Cretaceous sequence, which mainly consists of chert and porcellanite with rare interbedded limestone, planktonic foraminifers are generally few in number and poorly preserved. Planktonic foraminifers were observed in only a few samples obtained by scraping the relatively soft chalk or limestone from the chert cobbles. Samples 198-1214A-2R-1, 0-9 cm, to 4R-1, 0-17 cm, yield moderately preserved uppermost Albian planktonic foraminifers, including few Hedbergella delrioensis, Hedbergella almadenensis, Hedbergella simplex, Hedbergella planispira, Costellagerina libyca, Globigerinelloides bentonensis, Globigerinelloides ultramicrus, Heterohelix moremani, and Ticinella roberti. This interval is assigned to the Rotalipora appenninica Zone (KS16) based on the presence of rare specimens of the nominal taxon. Poorly preserved assemblages are present in Samples 198-1214A-5R-1, 19-23 cm, to 7R-1, 2-4 cm, which contain rare Ticinella primula, Hedbergella delrioensis, and G. bentonensis. The presence of Biticinella breggiensis in Sample 198-1214A-9R-1, 8-11 cm, permits the identification of the B. breggiensis Zone (KS14). The underlying interval from Samples 198-1214A-10R-1, 13-15 cm, to 16R-1, 29-30 cm, belong to the T. primula Zone (KS13). The presence of very small hedbergellids from Samples 198-1214A-17R-1, 27-28 cm, to 19R-1, 35-36 cm, is indicative of the Hedbergella planispira Zone (KS12). Sample 198-1214A-20R-1, 23-24 cm, is assigned to the Ticinella bejaouaensis Zone (KS11) (late Aptian) based on the presence of few Ticinella bejaouaensis and Hedbergella trocoidea. No planktonic foraminifers were observed in Core 198-1214A-23R, which contains a noncalcareous and organic-rich interval correlated with the lower Aptian Selli horizon (OAE1a). In the oldest core recovered in Hole 1214A, the presence of Hedbergella sigali, "H. delrioensis," and Globigerinelloides sp. in the absence of leupoldinids and clavihedbergellids indicates the Hauterivian Hedbergella sigali-"H. delrioensis" Zone.
Benthic foraminifers were examined in selected samples (Table T3). They are well preserved and common in abundance in the Neogene but are generally poorly preserved (some are completely replaced by silica) and rare in abundance in the Cretaceous.
Paleodepth estimates are based on the work of Pflum and Frerichs (1976), Woodruff (1985), and van Morkhoven et al. (1986) for the Neogene section. For the Cretaceous section, estimates are mainly based on the studies of Kaiho (1998), Holbourn et al. (2001), and backtracked paleodepth curves from the DSDP and Ocean Drilling Program (ODP) data of Kaiho (1999).
The only Pleistocene sample examined (Sample 198-1214A-1R-CC) contains a benthic assemblage similar to those observed at other Shatsky Rise sites, represented by Cibicidoides wuellerstorfi, Gyroidinoides girardanus, Oridorsalis umbonatus, Pyrgo spp., abundant Uvigerina hispida, and Uvigerina hispidocostata. This assemblage is indicative of upper abyssal depths (2000-3000 m).
Because of poor core recovery, all samples were scraped from the edges of indurated lithologies. In Samples 198-1214A-2R-1, 0-9 cm, through 5R-1, 19-23 cm (uppermost Albian), benthic assemblages are generally represented by Protosangularia albiana, Dentalina spp., Nodosaria spp., and abundant agglutinated species (Dorothia gradata, Gaudryina dividens, Marssonella praeoxycona, and Spiroplectinella excolata). In addition to these benthic foraminifers, Sample 198-1214A-7R-1, 4-6 cm, contains a diverse benthic assemblage including Conorotalites aptiensis, abundant Gyroidinoides infracretaceus, Hanzawaia compressa, Pleurostomella spp., Spiroplectammina sp., and Pseudoclavulina sp. In Samples 198-1214A-9R-1, 9-11 cm, through 19R-1, 35-37 cm (upper Albian-lower Aptian), benthic assemblages are represented by Gyroidinoides infracretaceus, Protosangularia albiana, Dentalina spp., Dorothia conula, and G. dividens. Buliminella spp. are also present in Samples 198-1214A-16R-1, 28-29 cm, and 19R-1, 35-37 cm. Lenticulina spp., one of the characteristic groups in the Lower Cretaceous at other Shatsky Rise sites, has a sporadic presence and very low abundances at Site 1214. Aptian Sample 198-1214A-22R-1, 32-33 cm, contains very poorly preserved Gavelinella spp. and Gyroidinoides infracretaceus. Samples 198-1214A-23R-1, 54-66 cm, through 23R-1, 93-94 cm, from the OAE1a interval contain no benthic foraminifers. Sample 198-1214A-25R-1, 19-21 cm, (early Hauterivian) contains Gavelinella intermedia, Buliminella spp., and Marssonella praehauteriviana.
Holbourn et al. (2001) assign a "middle-lower bathyal (1000-2000 m)" depth for benthic foraminiferal assemblages dominated by diverse nodosariids, rotaliids, and agglutinated taxa with calcareous cements. Upper Albian-Aptian benthic assemblages observed at Site 1214 are generally similar to this "middle-lower bathyal" assemblage but lack the diverse nodosariids, probably because of poor preservation and the small sample size examined. Furthermore, the presence of Protosangularia albiana in this interval, one of the characteristic taxa in the Early to mid-Cretaceous, indicates depths of ~1500-2500 m (lower bathyal-uppermost abyssal), according to Kaiho (1998, 1999).
One sample was examined in Hole 1214A to help constrain the age of green and black claystones and porcellanites in Core 198-1214A-23R that were characterized by the absence of other microfossils. Well-preserved radiolarians were found in Sample 198-1214A-23R-1, 47-49 cm, taken from the greenish gray clay interval between the thin tuff layers (see "Lithostratigraphy"). This sample is characterized by the presence of Archaeodictyomitra excellens (Tan), Archaeodictyomitra(?) lacrimula (Foreman), Archaeodictyomitra chalilovi (Aliev), Cryptamphorella clivosa (Aliev), Eucyrtis micropora (Squinabol), Pseudodictyomitra carpatica (Lozyniak), Pseudodictyomitra lanceloti (Schaaf), Pseudodictyomitra leptoconica (Foreman), Sethocapsa (?) orca (Foreman), Syringocapsa sp. cf. Stylosphaera coronata Steiger sensu Erbacher (1994), Thanarla conica (Aliev), Thanarla pulchra (Squinabol), and Wrangellium puga (Schaaf). There are many nassellarian species in this sample, and dominant genera include Archaeodictyomitra, Pseudodictyomitra, Sethocapsa, Thanarla, and Cryptamphorella. Baumgartner et al. (1995) report that P.carpatica ranges from Zone UAZ11 to Zone UAZ21 (Late Jurassic to Barremian). However, more recent studies by Premoli Silva et al. (1999) suggest that this species occurs in the Selli level (early Aptian) in Italy, thereby extending its range. Furthermore, the radiolarian assemblage of this sample does not contain the genera Pantanellium or Podobursa. The last occurrences (LOs) of these genera have been reported by Erbacher and Thurow (1997) to lie in the lowermost part of the Selli level. Therefore, this assemblage indicates an age of late early Aptian and suggests that these sediments were deposited during the middle to upper part of the OAE1a.