Calcareous nannofossil zonation of the Jurassic-Cretaceous boundary interval and correlation with the geomagnetic polarity timescale

Bralower, Timothy J.; Monechi, Simonetta; Thierstein, Hans R.

doi:10.1016/0377-8398(89)90035-2

Cited by 185 publications

(173 citation statements)

References 27 publications

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“…Therefore, Cores 8O1B-31R through -21R are assigned to an undifferentiated Kimmeridgian to middle Tithonian. A diverse nannofossil assemblage was recovered in Section 801B-25R-CC, enabling assignment to the Hexalithus noelae Subzone of Bralower et al (1989), which spans magnetic polarity chrons of upper M20r through lower Ml9n of middle Tithonian. The presence of the short-ranging nannofossil Umbria granulosa minor further limits the age assignment in this sample to the upper half of this subzone, corresponding to upper M20n through lower M19n .…”

Section: Middle Oxfordian To Lowest Tithonian (439-4125 Mbsf; Cores mentioning

confidence: 99%

Jurassic through Early Cretaceous Sedimentation History of the Central Equatorial Pacific and of Sites 800 and 801

Ogg¹,

Stattegger²,

Behl³

1992

Proceedings of the Ocean Drilling Program

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Sedimentation in the central Pacific during the Jurassic and Early Cretaceous was dominated by abundant biogenic silica. A synthesis of the stratigraphy, lithology, petrology, and geochemistry of the radiolarites in Sites 801 and 800 documents the sedimentation processes and trends in the equatorial central Pacific from the Middle Jurassic through the Early Cretaceous. Paleolatitude and paleodepth reconstructions enable comparisons with previous DSDP sites and identification of the general patterns of sedimentation over a wide region of the Pacific.Clayey radiolarites dominated sedimentation on Pacific oceanic crust within tropical paleolatitudes from at least the latest Bathonian through Tithonian. Radiolarian productivity rose to a peak within 5° of the paleoequator, where accumulation rates of biogenic silica exceeded 1000 g/cm 2 /m.y. Wavy-bedded radiolarian cherts developed in the upper Tithonian at Site 801 coinciding with the proximity of this site to the paleoequator. Ribbon-bedding of some radiolarian cherts exposed on Pacific margins may have formed from silicification of radiolarite deposited near the equatorial high-productivity zone where radiolarian/clay ratios were high. Silicification processes in sediments extensively mixed by bioturbation or enriched in clay or carbonate generally resulted in discontinuous bands or nodules of porcellanite or chert, e.g., a "knobby" radiolarite. Ribbon-bedded cherts require primary alternations of radiolarian-rich and clay-rich layers as an initial structural template, coupled with abundant biogenic silica in both layers. During diagenesis, migration of silica from clay-rich layers leaves radiolarian "ghosts" or voids, and the precipitation in adjacent radiolarite layers results in silicification of the inter-radiolarian matrix and infilling of radiolarian tests. Alternations of claystone and clay-rich radiolarian grainstone were deposited during the Callovian at Site 801 and during the Berriasian-Valanginian at Site 800, but did not silicify to form bedded chert.Carbonate was not preserved on the Pacific oceanic floor or spreading ridges during the Jurassic, perhaps due to an elevated level of dissolved carbon dioxide. During the Berriasian through Hauterivian, the carbonate compensation depth (CCD) descended to approximately 3500 m, permitting the accumulation of siliceous limestones at near-ridge sites. Carbonate accumulation rates exceeded 1500 g/cm 2 /m.y. at sites above the CCD, yet there is no evidence of an equatorial carbonate bulge during the Early Cretaceous. In the Barremian and Aptian, the CCD rose, coincident with the onset of mid-plate volcanic activity.Abundance of Fe and Mn and the associated formation of authigenic Fe-smectite clays was a function of proximity to the spreading ridges, with secondary enrichments occurring during episodes of spreading-center reorganizations. Callovian radiolarite at Site 801 is anomalously depleted in Mn, which resulted either from inhibited precipitation of Mn-oxides by lower pH of interstitial waters in...

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Section: Middle Oxfordian To Lowest Tithonian (439-4125 Mbsf; Cores mentioning

confidence: 99%

Jurassic through Early Cretaceous Sedimentation History of the Central Equatorial Pacific and of Sites 800 and 801

Ogg¹,

Stattegger²,

Behl³

1992

Proceedings of the Ocean Drilling Program

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“…The rare Jurassic nannofossils observed in sediments recovered during Leg 129 occur in the Oxfordian-Tithonian interval, in addition to sparse specimens of Watznaueria in older layers. For the Late Jurassic we used the scheme proposed by Bralower et al (1989), who calibrated nannofossil events with magnetic anomalies.…”

Section: Biostratigraphymentioning

confidence: 99%

Calcareous Nannofossil Biostratigraphy of Mesozoic Sediments Recovered from the Western Pacific, Leg 129

Erba¹,

Covington²

1992

Proceedings of the Ocean Drilling Program

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Calcareous nannofossils were studied from Jurassic and Cretaceous sediments drilled in the western Pacific during Ocean Drilling Program Leg 129. Mesozoic sediments at Sites 800, 801, and 802 are dominated by volcaniclastic turbidites, claystones, porcellanites, and radiolarites. Pelagic limestones are limited to the middle Cretaceous, and a few calcareous claystones were recovered in the Upper Jurassic section at Site 801.We documented the distribution of nannofossils, their total abundance, preservation, and relative species abundance based on semiquantitative and qualitative studies. Preservation of the calcareous nannofloras is poor to moderate, and the total abundance fluctuates from rare to very abundant. Marker species proposed for the middle and Late Cretaceous were recognized, allowing the application of standard nannofossil biozonations.At Site 800 calcareous nannofloras are abundant and moderately preserved in the Aptian-Cenomanian, and nannofossil biostratigraphy constitutes the basic stratigraphic framework for this interval.Radiolarians are the most abundant and persistent group throughout the sequence drilled at Site 801. Long intervals are barren of nannofloras and assemblages are usually characterized by low abundance and poor preservation. Nannofossil biostratigraphy was applied to the upper Aptian-Cenomanian interval and a few marker species were recognized for the late Tithonian.At Site 802 Cretaceous biostratigraphy is mainly based on calcareous nannofossil biozones corroborated by radiolarian and palynomorph events in the late Aptian-Coniacian age interval. A hiatus was indicated between the Santonian and the late Campanian, and another is suspected in the interval between the Cenomanian and the Coniacian.

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“…As sample G-56 was taken from the lower part of the Lower Tithonian Malmica Zone, the pres ence of N. globulus mi nor changes the known strati graphi cal range of this nannofossil. Ac cord ing to Bralower et al (1989), N. globulus mi nor ap peared in the Up per Tithonian (M19n magnetozone). Michalík et al (2009) have shown the first oc cur rence (FO) of this taxon in the M18r magnetozone (bed C27E, above their J/K bound ary).…”

Section: Microfossil Zonesmentioning

confidence: 94%

Integrated biostratigraphy and carbon isotope stratigraphy of the Upper Jurassic shallow water carbonates of the High-Tatric Unit (Mały Giewont area, Western Tatra Mountains, Poland)

Pszczółkowski

Grabowski²,

Wilamowski³

2017

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Calcareous nannofossil zonation of the Jurassic-Cretaceous boundary interval and correlation with the geomagnetic polarity timescale

Cited by 185 publications

References 27 publications

Jurassic through Early Cretaceous Sedimentation History of the Central Equatorial Pacific and of Sites 800 and 801

Jurassic through Early Cretaceous Sedimentation History of the Central Equatorial Pacific and of Sites 800 and 801

Calcareous Nannofossil Biostratigraphy of Mesozoic Sediments Recovered from the Western Pacific, Leg 129

Integrated biostratigraphy and carbon isotope stratigraphy of the Upper Jurassic shallow water carbonates of the High-Tatric Unit (Mały Giewont area, Western Tatra Mountains, Poland)

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