Cretaceous-Tertiary Boundary Section Research Articles

Maastricthtian ammonite and inoceramid ranges from Bay of Biscay Cretaceous-Tertiary boundary sections

New collecting of ammonites and inoceramid bivalves from Cretaceous-Tertiary boundary sections exposed al Sopelana and Zumaya, Spain, and Hendaye and Bidart (Biarritz), France, has led to better understanding of molluscan biostratigraphy in each of these coastal exposures. Ali of these sections can be lithologically correlated. At all of the sections, ammonites have now been found within the last meter of the Cretaceous. Also, in all of the sections, inoceramid bivalves disappear near the base A . mayaronensis planktonic foram zone, the only exception being the small, enigmatic bivalve genus Tenuipteria , which ranges up to the Cretaceous-Tertiary boundary.

Field-guide excursion to the Cretaceous-Tertiary boundary section at Zumaya (northern Spain)

The Basco-Cantabrian Domain (Basco-Cantabrian Basin of some authors) represents the eastern part of the southern side of the Bay of Biscay. In Late Cenomanian, as a result of previous environmental and morphological modifications, it was composed of two approximately E-W oriented elements, which are, from north to south: A deep marine area and a marine shelf called the Navarro-Cantabrian Platform. The deep marine area comprised two major elements that were, from north to south: a) An E-W oriented and westward open depression: the Saint-lean-de-Luz Trough; b) A topographically higher region: the Biscay-Guipúzcoa Shallows. It connected at north, through a northward dipping slope, with the St-J-Luz Trough. At south, it rose up to the Navarro-Cantabrian Platform and its limit might correspond to a great structural element: the Bilbao Fault (Amiot, Floquet, Mathey, 1982; Engeser et al., 1984). The southeastern part of the B-C Shallows was a small, always E-W trending despression: the Plencia Trough. On the contrary, its eastern part was a shoal: the Basque Shoal, whose some sectors are small platforms of inner type, whereas some other are emerged. The eastern limit of the whole deep marine area could correspond with an alignment of diapirs: the. Line of Navarra Diapirs (Rat, 1983). During the Cretaceous, that line separated an Occidental and Navarro-Cantabrian domain from an Oriental and Pyrenean one.

Shiva impact event and its implications for Deccan Volcanism and Dinosaur Extinction

We have identified a buried 500 km diameter Shiva structure on the western shelf of India as a possible impact crater that formed at the Cretaceous-Tertiary (KT) boundary time. The location of the Shiva crater was initially suggested between India-Seychelles block, when Seychelles was part of the Indian Plate at its western margin around 65 Ma. This work refines previous interpretations of the structure, morphology and the extent of the Shiva crater, which now appears to be located entirely on the Mumbai Offshore Basin encircling the Bombay High area. The Shiva crater is largely submerged on the passive western continental shelf and is buried by 7 km thick strata of post-impact Cenozoic sediments. It is the largest impact crater known on Earth, about 500 km diameter and is a rich source of oil and gas. It has the morphology of a complex peak ring structure with a multiring basin configuration, thus providing an ideal structural trap for petroleum entrapment. Four different ring structures have been identified, where the inner peak ring represents the central uplift of the Bombay High area with a core of Neoproterozoic granite basement. Inside the peak ring, a series of rugged mountainous peaks tower more than 7 km above the basin floor. We speculate that the Shiva bolide (~40 km diameter) crashed obliquely on the western continental shelf of India around 65 Ma, excavating the crater, shattering the lithosphere, initiated the rifting between India and the Seychelles and triggered the acceleration of the Indian Plate northward. The Cretaceous-Tertiary boundary sections of India have yielded several proximal ejecta components linked to the Shiva event such as shocked quartz, spherules and glass shards and iridium-rich alkaline melt rocks. Other cosmic signatures at the KT boundary of India from the vapourized meteorite include iridium anomaly, natural fullerenes, nickelrich spinels and magnetic nanoparticles. Although the Reunion hotspot responsible for Deccan eruption was close to the Shiva crater in time and space, impact did not trigger the hotspot because the first phase of the Deccan volcanism preceded the Shiva impact by 400,000 years or more. Two large impacts such as Shiva and Chicxulub in quick succession on the antipodal position, in concert with Deccan eruption, would have devastating effects globally leading to climatic and environmental calamity that wiped out the dinosaurs and many other organisms at the KT boundary.

Impact and extinction in remarkably complete Cretaceous-Tertiary boundary sections from Demerara Rise, tropical western North Atlantic

Ocean Drilling Program (ODP) Leg 207, on the Demerara Rise in the western tropical North Atlantic, recovered multiple Cretaceous-Paleogene boundary sections containing an ejecta layer. Sedimentological, geochemical, and paleontological changes across the boundary closely match patterns expected for a mass extinction caused by a single impact. A normally graded, ~2-cmthick bed of spherules that is interpreted as a primary air-fall deposit of impact ejecta occurs between sediments of the highest Cretaceous Plummerita hantkeninoides foraminiferal zone and the lowest Paleogene P0 foraminiferal zone. There are no other spherule layers in the section. In addition to extinction of Cretaceous taxa, foraminiferal abundance drops from abundant to rare across the boundary. Ir concentrations reach a maximum of ~1.5 ppb at the top of the spherule bed, and the Ir anomaly is associated with enrichment in other siderophile elements. We attribute the unusually well-preserved and relatively simple stratigraphy to the fact that Demerara Rise was close enough (~4500 km) to the Chicxulub impact site to receive ~2 cm of ejecta, yet was far enough away (and perhaps sheltered by the curve of northern South America) to have been relatively unaffected by impact-induced waves.

High-resolution geochemical record of Cretaceous-Tertiary boundary sections in Mexico: New constraints on the K/T and Chicxulub events

The investigation of eight Cretaceous-Tertiary (K/T) sections in Mexico, based on major and trace element, platinum group element (PGE), stable isotope, and multivariate statistical analysis, reveals a complex depositional history across the Chicxulub and K/T boundary events. At the biostratigraphically determined K/T boundary, a minor but significant Ir-dominated PGE anomaly (0.2–0.8 ng/g) is present in most sections. This Ir anomaly originated from an impact event and is always stratigraphically and geochemically decoupled from the underlying spherule-rich ejecta deposit related to the Chicxulub event. In all sections examined, one to three glass spherule ejecta layers and one or two chondrite-dominated PGE anomalies are separated by a bioturbated siliciclastic deposit and/or hemipelagic marl, which indicates the occurrence of at least two impact events separated by a considerable amount of time. In addition, bentonite layers and Pt and Pd-dominated PGE anomalies below and above the K/T boundary indicate volcanic activity. Above the K/T boundary, reduced bioproductivity is documented by a decrease in the biogenically bound fraction of nutrients and fluctuating ratios of immobile elements (e.g., Ti/Zr). Variations in detrital elements reflect changes in the depositional environment. Carbon and oxygen isotope and trace element distribution patterns indicate a gradually changing climate during the latest Maastrichtian, an abrupt change at the K/T boundary, and a slight recovery during the lowermost Paleocene.

Dinoflagellate cyst record of the deep-sea Cretaceous-Tertiary boundary at Uzgruň, Carpathian Mountains, Czech Republic

Abstract The record of organic-walled dinoflagellate cysts in deep-sea facies across the Cretaceous-Tertiary boundary is poorly known. A detailed study of uppermost Maastrichtian-lowermost Danian Tethyan deep-sea flysch sediments deposited below the carbonate compensation depth at Uzgruň, in the Czech Republic, has yielded numerous and relatively well-preserved dinoflagellate cysts. Their distribution allows the Cretaceous-Tertiary boundary to be placed within a 73 cm interval, within which an iridium anomaly occurs. Assemblages show no major shifts within the boundary interval, but gradual changes were recorded that possibly relate to sea-level fluctuations and/or nutrient availability. High concentrations of peridinioids appear to indicate upwelling in this part of the Tethys near the Cretaceous-Tertiary boundary. The presence of thermophilic dinoflagellate cysts throughout the section points to a stable, warm-temperate to subtropical climate during the latest Maastrichtian and earliest Danian. Events, such as the Areoligera sp. acme, Manumiella seelandica acme and the Spinidinium sp. acme, known from other Cretaceous-Tertiary boundary sections around the world, were recognized within the studied material.

Marine Cretaceous-Tertiary boundary section in southwestern South Dakota: Comment and Reply

In a similar vein to what Dana posited for Hall's geosynclinal theory for the origin of mountain belts—that it presented “a theory for the origin of mountains with the origin of mountains left out” (p. 55, King, 1977)—[Terry et al. (2001)][1] promote the presence of a Cretaceous-Tertiary (K-

Marine Cretaceous-Tertiary boundary section in southwestern South Dakota

A distinctive zone of disrupted strata, which we interpret as a distal manifestation of the end-Cretaceous Chicxulub impact event, occurs over 300 km 2 in southwestern South Dakota. This disrupted zone is within the Fox Hills Formation, ranges from 0.5 to 5 m in thickness, and contains large-scale slump-roll structures, clastic dikes, flame structures, and massive, homogenized beds. The zone is ∼0.5 m above a belemnite fauna Sr dated as 67.6 ± 0.5 Ma, contains scaphitid ammonites characteristic of the Jeletzkytes nebrascensis ammonite zone of the Fox Hills Formation, and is capped by a 0.5–4-cm-thick brownish-black mudstone that contains spherules. Pollen of the late Maastrichtian Wodehouseia spinata palynostratigraphic zone occurs immediately above and below the disrupted zone. The disrupted zone is overlain by an additional 25 m of marine Fox Hills Formation. These stratigraphic relationships suggest that the upper part of the Fox Hills Formation in this part of South Dakota is Paleocene; that the Western Interior Seaway was locally present well into the Paleocene; and that scaphitid ammonites may range the Cretaceous-Tertiary (K-T) boundary.

Paleobotanical evidence for ecosystem disruption at the Cretaceous-Tertiary boundary from Wood Mountain, Saskatchewan, Canada

A continuous, subsurface Cretaceous-Tertiary boundary section, including the boundary clay within an 87 cm thick lignite, has been recovered from a core hole near Wood Mountain, Saskatchewan, Canada. The lignite-encompassed clay layer with geochemical anomaly indicates that peat deposition was continuous across the boundary. Core data indicate that, locally, a pre-boundary, conifer-dominated swamp was abruptly replaced by an angiosperm-dominated, herbaceous wetland. Sudden extermination of the dominant forest elements indicates mass kill at the level of the boundary and supports the theory of extraterrestrial impact accompanied by catastrophic destruction. Devastation of the standing vegetation may have been caused by one or more of the killing agents predicted to have accompanied impact, including freezing temperatures caused by atmospheric dust, acid rain, thermal pulse, and shock waves. There is no evidence supporting wildfires as a killing agent. Vegetational change apparent within the boundary interval is consistent with observations elsewhere in the Western Interior of North America of abrupt replacement of an ecosystem. Early Paleocene reestablishment of the cypress swamp vegetation is calculated to have taken from 1 to 5 millennia.

Geochemical Markers of the Cretaceous-Tertiary Boundary Event at Brazos River, Texas, USA

The Cretaceous-Tertiary boundary sites around the Gulf of Mexico are close to the Chixculub impact site and are relatively well studied, yet much remains to be learned about them. Therefore, the first integrated study of carbon, soot, and fullerenes in a Cretaceous-Tertiary boundary section was undertaken at the Brazos-1 site on the Brazos River in Texas at the most complete section of end Cretaceous and basal Paleocene deposits on the Texas segment of the Gulf Coast area. Up to 409 ppm of native sulfur (S o) were serendipitously discovered in a spherule-bearing unit of the BR-1 section, and lesser amounts were found in spherule-bearing units of nearby Brazos riverbed sections in a section on Darting Minnow Creek. The isotopic composition, δ 33S = −12.97‰, δ 34S = −24.89‰, and δ 36S = −46.4‰, implies that this S o cannot have come to Earth by the impactor that formed the Chicxulub crater, but, most likely, was produced by sulfate-reducing bacteria during a local, transient bacterial bloom for which the sulfate was provided by CaSO 4-bearing spherules. Carbon and soot were determined in twelve samples representing all units of BR-1 from the Cretaceous Corsicana/Kemp Formation to the Tertiary Kincaid Formation. A significant increase of C and soot contents, up to 2.2×10 4 ppm and 1.4×10 4 ppm, respectively, occurs in a sandy bed at the top of the KT complex. Fullerenes were determined in fifty-four samples from all units of the same BR-1 section. Less than 1 ppb was reliably detected at the same sandy bed where the strongest Ir anomaly of the section is known to occur. It is suggested here that the Chicxulub impact 65 Ma ago ignited local wildfires that produced C, soot, and fullerene, which settled onshore, or near-shore, whence they were transported to the Brazos site by coastal flooding and associated sediment-laden water plumes moving offshore.

Palynology and sedimentology across a new marine Cretaceous-Tertiary boundary section on Nuussuaq, West Greenland

A new northern high-latitude Cretaceous-Tertiary (K-T) boundary section has been studied at Annertuneq on the north coast of Nuussuaq, West Greenland. The boundary section is situated in a succession of homogeneous dark mudstone deposited in a marine-slope environment. Identification of the boundary is based on the presence of the latest Maastrichtian palynomorphs Palynodinium grallator , Disphaerogena carposphaeropsis , Manumiella spp., and Wodehouseia quadrispina below the boundary and on the first occurrence of the earliest Danian species Senoniasphaera inornata above the boundary. Variations in sporomorph and dinoflagellate cyst abundances indicate latest Maastrichtian regression followed by early Danian transgression. The transgressive phase can be subdivided into three high-frequency transgressive-regressive cycles. Each cycle indicates upwelling and transgression, mixing with low-latitudinal water masses, and ocean conditions suggested by the peak occurrences of Senegalinium spp., Trithyrodinium fragile , and Spongodinium delitiense , respectively.

Pseudomorphs of impact spherules from a Cretaceous-Tertiary boundary section at Shell Creek, Alabama

During a biostratigraphic investigation of a Cretaceous-Tertiary boundary section at Shell Creek, Alabama dark green spherules with distinctive morphologies were serendipitously found in the lower Danian basal Clayton sand. With the exception of in the upper 30 cm, they were found throughout the sand, upwards from an erosional contact separating the sand from the underlying upper Maastrichtian Prairie Bluff Chalk. Additional studies revealed that the spherules exhibit the morphologies of splash-form tektites and that their original composition has been altered to a smectite external layer with a calcite core. The presence of spherules with similar morphologies and size distribution in K-T boundary sections at Beloc (Haiti) and in Arroyo El Mimbral (northeastern Mexico) leads to the deduction that the Shell Creek spherules represent altered impact ejecta. Impact glasses, Ni spinels and shocked mineral grains were searched for extensively, but intense alteration and dilution by detrital quartz sand have made it unlikely that such supporting evidence of an impact origin will be found at this site. Nonetheless, the large sizes of the microtektite pseudomorphs, which are well over 1 mm in diameter, and abundance (the total fluence is about 2 g/cm 2), makes this location an important corroboration of a proximal site for the K-T impact.

Planktonic foraminiferal biostratigraphy and palaeoceanography of the Cretaceous-Tertiary boundary section at Bidart, south-west France

A planktonic foraminiferal biostratigraphy of the relatively complete Cretaceous-Tertiary (K/T) boundary section at Bidart, south-west France, is given. With the exception of Rugoglobigerina hexacamerata Brönnimann and Guembelitria cretacea (Cushman), all Cretaceous planktonic foraminifera became extinct at the K/T boundary. Thanetian age strata are for the first time reported from Bidart, and a significant hiatus representing 350-750 kyr I is detected at the Danian/Thanetian boundary. Population changes within the Maastrichtian planktonic foraminiferal faunas are generally similar to those of other K/T boundary sections but large 'globotruncanids' increase in numbers close the boundary, rather than decrease as elsewhere. This change in faunal composition 2.5 m below the boundary correlates with changes in lithology (from grey to red micrite) and 87 Sr/ 86Sr ratio, an increase in δO 18 and a decrease in δ 13C. This evidence suggests that the palaeoceanography of the Bidart region changed from a Tethyan to a North Atlantic dominated setting towards the end of the Cretaceous.

Dinoflagellate and calcareous nannofossil response to sea-level change in Cretaceous-Tertiary boundary sections

Research Article| February 01, 1992 Dinoflagellate and calcareous nannofossil response to sea-level change in Cretaceous-Tertiary boundary sections Daniel Habib; Daniel Habib 1Queens College, City University of New York, Flushing, New York 11367 Search for other works by this author on: GSW Google Scholar Shimon Moshkovitz; Shimon Moshkovitz 2Geological Survey of Israel, Jerusalem 95501, Israel Search for other works by this author on: GSW Google Scholar Cynthia Kramer Cynthia Kramer 3Hamilton College, Clinton, New York 13323 Search for other works by this author on: GSW Google Scholar Author and Article Information Daniel Habib 1Queens College, City University of New York, Flushing, New York 11367 Shimon Moshkovitz 2Geological Survey of Israel, Jerusalem 95501, Israel Cynthia Kramer 3Hamilton College, Clinton, New York 13323 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1992) 20 (2): 165–168. https://doi.org/10.1130/0091-7613(1992)020<0165:DACNRT>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Daniel Habib, Shimon Moshkovitz, Cynthia Kramer; Dinoflagellate and calcareous nannofossil response to sea-level change in Cretaceous-Tertiary boundary sections. Geology 1992;; 20 (2): 165–168. doi: https://doi.org/10.1130/0091-7613(1992)020<0165:DACNRT>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Stratigraphic sections in south-central Alabama were studied to test palynological evidence of sea-level change across the Cretaceous-Tertiary boundary. New evidence from both calcareous nannofossils and dinoflagellate cysts places the regional disconformity in Alabama (Type 1 sequence boundary) virtually at the K-T boundary. This suggests that sea-level fall may have contributed to the mass-extinction event. Dinofagellate diversity varies between systems tract components of coastal onlap. This parameter is useful for interpreting sea-level change in this part of the section, because dinoflagellates did not participate in the mass extinction. The iridium spikes in the roadcut near Braggs are of earliest Danian age and correlate in relative magnitude with the lower values reported from directly above the K-T boundary in the Gubbio stratotype section. Iridium was concentrated in marine flooding surfaces in episodes of higher productivity of algal organic matter at the time when the iridium-enriched ocean encroached on the shelf during the first Cenozoic episode of sea-level rise. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

The Cretaceous-Tertiary boundary at Gubbio revisited: vertical extent of the Ir anomaly

The classical Gubbio (Italy) Cretaceous-Tertiary boundary section has been resampled for both magnetostratigraphy and iridium. Paleomagnetic samples were taken over 7 m in the Maastrichtian and 6 m in the Paleocene. Previous results obtained a decade ago are confirmed. The reversal sequence is well defined and the individual reversals are somewhat more precisely located. A noticeable difference is the location of the position of the 29N/29R limit which may be lowered by 20–30 cm in the stratigraphic column. This would imply that the KTB occurs near the middle of chron 29R. Iridium measurements were made on samples from both shales and surrounding limestone beds from 2 m below to 3 m above the boundary: these measurements indicate that Ir is associated with clay minerals. Concentrations in the two types of samples are indeed compatible when reduced to a carbonate-free basis. Iridium concentrations stand above background over almost 3 m of section, corresponding to half a million years based on magnetostratigraphy. This is likely to indicate a protracted duration of the (external or internal) source of iridium, on top of which the main (short-lived) KTB anomaly proper stands.

Paleoceanography of the eastern Indian Ocean from ODP Leg 121 drilling on Broken Ridge

Broken Ridge, in the eastern Indian Ocean,is overlain by about 1,600 m of middle Cretaceous to Pleistocene tuffaceous and carbonate sediments that record the oceanographic history of southern hemisphere mid-to high-latitude regions. Prior to about 42 Ma, Broken Ridge formed the northern part of the broad Kerguelen-Broken Ridge Plateau. During the middle Eocene, this feature was split by the newly forming Southeast Indian Ocean Ridge; since then, Broken Ridge has drifted north from about 55° to 31°S. The lower part of the sedimentary section is characterized by Turonian to Santonian tuffs that contain abundant glauconite and some carbonate. The tuffs record a large but apparently local volcanic input that characterized the central part of Broken Ridge into the early Tertiary. Maestrichtian shallow-water(several hundred to 1,000 m depth) limestones and cherts accumulated at some of the highest rates ever documented from the open ocean, 4 to 5 g (cm 2 10 3 yr) -1 . A complete (with all biostratigraphic zones) Cretaceous-Tertiary boundary section was recovered from site 752. The first 1.5 m.y. of the Tertiary is characterized by an order-of-magnitude reduction in the flux of biogenic sediments, indicating a period of sharply reduced biological productivity at 55°S, following which the carbonate and silica sedimentation rates almost reach the previous high values of the latest Cretaceous. We recovered a complete section through the Paleocene that contains all major fossil groups and is more than 300 m thick, perhaps the best pelagic Paleocene section encountered in ocean drilling. About 42 Ma, Broken Ridge was uplifted 2,500 m in response to the intra-plateau rifting event; subsequent erosion and deposition has resulted in a prominent Eocene angular unconformity atop the ridge. An Oligocene disconformity characterized by a widespread pebble layer probably represents the 30 Ma sea-level fall. The Neogene pelagic ooze on Broken Ridge has been winnowed, and thus its grain size provides a direct physical record of the energy of the southern hemisphere drift current in the Indian Ocean for the past 30 m.y.

Magnetic stratigraphy and magnetic mineralogy at the Cretaceous-Tertiary boundary section, Braggs, Alabama

The Cretaceous-Tertiary boundary is exposed in shallow marine coastal plain sediments near Braggs, Alabama. Magnetic stratigraphy across the boundary indicates that Chron 29R is represented by a stratigraphic thickness of 2.91 (±0.48)m. The average sedimentation rate in this chron is therefore 5.1 m/m.y. The apparent macrofaunal extinction at C29.15R is significantly below the nannofossil extinction event at C29.45R. In the pelagic realm, the microfaunal extinction event is consistently found between C29.7R and C29.8R. The discordance between the microfaunal and macrofaunal extinction events at Braggs, and between the microfaunal extinctions in pelgic sections and at Braggs, may be due to local changes in sedimentary environment in the Braggs section, which culminate in an erosional uncomformity at C29.15R. The minimum estimate for the apparent time lag between the two extinction events at Braggs is about 80,000 yr. Rock magnetic experiments and the analysis of magnetic separates indicate the presence of magnetite, hematite and pyrrhotite as potential magnetic remanence carries. Two phases of magnetite one detrital titanomagnetite and one euhedral low-titanium magnetite, have been identified by electron microscopy, X-ray diffraction and electron diffraction techniques. The euhedral low-titanium magnetite is fine grained (< 0.1 μm) and may be biogenic.