K Pg boundary

K-Pg Boundary Cretaceous-Paleogene Boundary Geology Pag

It's now called the Cretaceous-Paleogene boundary, or K-Pg boundary. It's habit to use the old term, but I'll try harder in the future. Not only that, but in the video, I said that K. The Paleogene Period (65-23 million years ago) follows this huge extinction with the age of mammals. Big Bend National Park is one of the few places on public land that preserves this transition in the geologic record. This transition, from the Cretaceous (K) to the Paleogene (Pg), is called the K-Pg boundary

Mass Extinctions | Biology for Majors II

The K-PG Boundary and Dinosaur Extinction (aka K-T

  1. Many whole genome duplications seem to be clustered in time around the K/Pg boundary. Both adaptive and neutral processes might have contributed to promote the establishment of polyploids. Fifteen years into sequencing entire plant genomes, more than 30 paleopolyploidy events could be mapped on the tree of flowering plants (and many more when also transcriptome data sets are considered)
  2. Changes in pollen and spore assemblages across the Cretaceous-Paleogene (K-Pg) boundary elucidate the vegetation response to a global environmental crisis triggered by an asteroid impact in Mexico 66 Ma.The Cretaceous-Paleogene boundary clay, associated with the Chicxulub asteroid impact event, constitutes a unique, global marker bed enabling comparison of the world-wide palynological.
  3. This transition, known as the K-Pg boundary, is visible in the geologic record and marks one of the greatest mass extinctions of all time, and the end of the dinosaurs. Big Bend has the southernmost known exposure of terrestrial sedimentary rocks recording the K-Pg boundary in the United States
  4. This period marks the Cretaceous-Paleogene (K-Pg; formerly K-T) boundary separating the Mesozoic Era (age of dinosaurs) and Cenozoic Era (age of mammals). The size of the impactor was calculated to be at least 10 km (~6 mi) in diameter and to have conveyed at least 1.3 yottajoules ( 10 24 ) of energy (Durand-Manterola and Cordero-Tercero, 2014), equivalent to ~6 million 'Tsar Bomba' nuclear devices
  5. The Cretaceous-Paleogene (K-Pg) boundary mass extinction (ca. 66 Ma) is one of the most devastating events in the history of life, mark-ing the end of the dinosaur era (Bambach, 2006). Although Deccan Traps volcanism may have contributed to environmental perturbations, the mass extinction at the K-Pg boundary is widel
  6. Impact markers at hundreds of sites globally co-occur with the deposition of the Cretaceous-Paleogene (K/Pg) boundary clay and include elevated abundances of siderophilic elements such as iridium, osmium, and nickel, as well as tektites and shocked quartz ( 1, 5, 6 )
  7. erals, impact spherules, and a distinct Ir concentration peak marking the boundary (3, 5). In more proximal sites, including those around the Gulf of Mexico, the K-Pg boundary typically consists of a serie

K-Pg境界(ケイ・ピージーきょうかい、英: Cretaceous-Paleogene boundary )とは地質年代区分の用語で、約6550万年前 の中生代と新生代の境目に相当する。 顕生代 において5回発生した 大量絶滅 のうちの最後の事件 [注釈 1] In conclusion, the persistence of archaic birds up to the K-Pg boundary in North America and the absence of identifiable members of modern orders show that this latest Cretaceous avifauna was still far from modern, and they underscore the extent to which the end-Cretaceous mass extinction has shaped avian diversity In the geologic record, the K-Pg event is marked by a thin layer of sediment called the K-Pg boundary, which can be found throughout the world in marine and terrestrial rocks. The boundary clay shows high levels of the metal iridium, which is rare in the Earth's crust but abundant in asteroids Some raw footage I edited together from my trip to see the K-Pg boundary in Colorado in summer 2019. The boundary itself is a few miles into the backcountry. The uppermost part of the Cretaceous is called the Maastrichtian and the lowermost part of the Tertiary (or Paleogene) is called the Danian, so some reports may describe the mass extinction event at the Maastrichtian-Danian boundary. In addition, the absolute age of the K-T (or K-Pg) boundary has been refined

Cretaceous-Paleogene extinction event - Wikipedi

  1. Big Bend is the only unit in the NPS where the Cretaceous-Paleogene Boundary (K-Pg; formerly K-T) is exposed and can be observed. These rocks were laid down 66 million years ago during the extinction event that wiped out the dinosaurs and three-quarters of plant and animal species on Earth
  2. ating approximately 80 percent of all species of animals at or very close to the boundary between the Cretaceous and Paleogene periods, about 66 million years ago
  3. The most recent of Earth's five largest mass extinctions occurred at the Cretaceous-Paleogene (K-Pg) boundary, about 66 million years ago. It led to the disappearance of the dinosaurs and coincided with the impact of a 10-km asteroid at Chicxulub, in the Yucatán peninsula (Alvarez et al., 1980; Schulte et al., 2010)

Posts about K-Pg boundary written by inquisitivebiologist. 7-minute read. Since it was coined in the year 2000 by Paul Crutzen and Eugene Stoermer, the term Anthropocene has taken the world by storm - pretty much in the same way as the phenomenon it describes Determining trends in Mesozoic dinosaur species-richness immediately prior to the K-Pg boundary is a contentious issue and has been the focus of numerous previous studies (e.g. [3,8-10]). Many different hypotheses have been proposed, but there are currently three schools of thought. The first, reviewed extensively by Brusatte et al The K-Pg boundary is found close to one of these ebb-and-flow depositional events. It lies near the boundary of the Tejas and Zuni Megasequences that represent the final two sedimentary packages deposited during the Flood. This offers a more satisfactory explanation of the sequence of fossils based on the ecological zonation of the pre-Flood.

[9] Studies of patterns of survival across the K‐Pg boundary suggest that nearly all freshwater families had only minor extinction, in contrast with terrestrial or marine families. Cartilaginous fish lost about 20% of families and teleost (bony) fish lost about 10% of families [ Patterson , 1993 ; MacLeod et al ., 1997 ] The K-Pg boundary section in northeastern Montana is a standard for examining patterns in the terrestrial realm, but few studies have examined the biotic changes at ecologically relevant spatial and temporal scales leading up to, across, and following the K-Pg boundary Paleocene mammals, K-Pg boundary, Paleocene, K/Pg Boundary Crocodile swim tracks from the latest Cretaceous of Europe ABSTRACT Recently discovered evidence of tracks in the continental beds of the Late Cretaceous Tremp Formation in the southern Pyrenees (NE Iberian Peninsula) has been identified as scratch marks made by buoyant crocodiles (K-Pg) boundary and linked to the ~65Ma Chicxulub impact crater led to the hypothesis that major wildfires were a consequence of the asteroid impact. Subsequently, several lines of evidence, including the lack of charcoal in North American sites, were used to argue against global wildfires

nmnh.typepad.co The K-Pg Boundary sections in Saskatchewan are also special because they contain fossils just below and just above the extinction, allowing paleontologists to tell how the extinction effected the biodiversity and how fast the recovery was Ronny Nalin, PhD, Geoscience Research Institute. References [1]Alvarez, L.W., et al., Extraterrestrial Cause for the Cretaceous-Tertiary Extinction. Science, 1980. 208(4448): p. 1095-1108. [2]Originally, this stratigraphic boundary was referred to in the literature as the K-T (Cretaceous-Tertiary) boundary, a notation that was subsequently abandoned for K-Pg (Cretaceous-Paleogene), which. A new study published in Paleobiology has found that many plant species changed dramatically at the K-Pg (Cretaceous-Paleogene) boundary in Argentina.1 Although secular scientists insist this change is caused by an extinction event, the more likely explanation involves pre-Flood environments and the progressive burial of ecosystems in the global Flood Abstract. The consequences of the Cretaceous-Paleogene (K-Pg) boundary (KPB) mass extinction for the evolution of plant diversity remain poorly understood, even though evolutionary turnover of plant lineages at the KPB is central to understanding assembly of the Cenozoic biota

The K-Pg boundary occurs at ∼216.6 m composite depth, calibrated to 66.02 Ma on an astronomically tuned time scale (Dinarès-Turell et al., 2014). We measured δ 13 C and δ 18 O on 10 species of planktic and 1 benthic foraminifera using a Thermo Finnigan MAT252 mass spectrometer equipped with an automated KIEL III carbonate preparation unit at Cardiff University, UK K-Pg boundary event deposits and distribution of ejecta vary with distance and direction from the Chicxulub crater, with considerable differences between proximal and distal sites, less than 1000 and more than 5000 km from the impact site, respectively (Fig. 1) (3, 5, 6). In the distal and mostly marine sections, the K-Pg boundary is com There are two possible origins for the soot at the K/Pg boundary: wildfires 21,27 and impact target rock 28,29. The amount of the stratospheric soot estimated here includes the soot from both wild.

The Cretaceous-Palaeogene (K/Pg) boundary interval is often penetrated by burrows, which may obscure stratigraphic and micropalaeontological records, leading to misinterpretations of the sequence of events spanning the K/Pg boundary About 66 million years ago (Ma) , at the boundary of the Cretaceous-Paleogene (K/Pg) period, a sudden mass extinction was triggered by the impact of a bolide, destroying an estimated three-quarters of Earth's plant and animal species. The long-term effects of this event varied across Earth, and little is known about the outcome in low-latitude regions of the world. On page 63 of this issue. Global Climate Change Driven by Soot at the K-Pg Boundary as the Cause of the Mass Extinction Kunio Kaiho 1 , Naga Oshima 2 , Kouji Adachi 2 , Yukimasa Adachi 2 , Takuya Mizukami 1 , Megumu Fujibayashi 3 , Ryosuke Saito 1 Affiliations Expand Affiliations 1 Department of.

Final Geology Exam - Geology 1050 with Yacobucci atImpact or eruptions: Are both to blame in the great end

The K-Pg boundary: Layer of rock shows how the dinosaurs died

INTRODUCTION. The mass extinction at the Cretaceous-Paleogene (K-Pg) boundary ~66.05 million years ago abruptly and irreversibly reshaped Earth's biosphere (1-4).In the geologic record, the K-Pg event is marked by a thin layer of clay, found so far in more than 350 marine and terrestrial sections across the globe (3, 5, 6).The boundary clay contains concentrations of iridium (Ir) and the. Records of the K-Pg boundary appear in layers of sedimentary rock called strata. These are laid down over time, resulting in a series of strata with the youngest at the top and the oldest at the bottom. Exploring the K-Pg boundary is just one example of how the geologic record is used to study our planet's 4.6-billion-year history Mass extinction of birds at the Cretaceous-Paleogene (K-Pg) boundary Nicholas R. Longricha,1, Tim Tokarykb, and Daniel J. Fielda aDepartment of Geology and Geophysics, Yale University, New Haven, CT 06520-8109; and bRoyal Saskatchewan Museum Fossil Research Station, Eastend, SK, Canada S0N 0T0 Edited by David Jablonski, University of Chicago, Chicago, IL, and approved August 10, 2011. Based on the fish, the dealer thought the site was a pond deposit that formed many thousands of years before the K-Pg boundary. But the more that DePalma mapped the site, the more he reconsidered Posts about K-Pg Boundary written by Amy Law. I had always wondered how the dinosaurs died out. I couldn't understand how just getting hit by an asteroid, or having volcanoes spew out ash could wipe them all out

While technically known now as the K/Pg Boundary, the name K/T is much more well-known! The fantastic thing about these wonderful little vials is that they contain three distinct layers of dirt. The lightest colour at the bottom comes from the Cretaceous sediments of North Dakota, famous for plentiful dinosaur fossils and being the last time dinosaurs roamed the Earth The K-Pg interval was recognized as a distinct sedimentological change between Units 9 and 10 of the LBF prior to the recognition that it contained the K-Pg boundary MS values differ slightly among three separate transects across the K/Pg boundary. These differences may result either from variations in primary depositional conditions or diagenetic effects following the K/Pg. In contrast to the greensands, grey clay rip-up clasts in the MFL exhibit anomalously low MS values (26-30) In 2015, Johnson hiked 110 miles of exposed K-Pg Boundary layer in North Dakota, seeking out fossils on the way. If you look down from the layer we were seeing dinosaurs all over the place, he says Outcrops located along the Brazos River, Texas, which contain the Cretaceous-Paleogene (K-Pg) boundary have been extensively studied for the last 30 years, and provide critical insight into the.

PSA Lithostratigraphic Examination of the K-PG Boundary in Northwestern South Dakota* . Jason Testin1. Search and Discovery Article #50803 (2013)** Posted June 30, 2013 *Adapted from poster presentation at AAPG Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 201 A geological section exposed in an abandoned quarry at Lechówka near Chełm represents the most complete record of the Cretaceous-Paleogene (K-Pg) boundary interval in Poland. Here, a thin clay layer with impact ejecta marks the K-Pg boundary, making Lechówka the single place in Poland with a record of the impact that killed off the dinosaurs To discover interordinal relationships of living and fossil placental mammals and the time of origin of placentals relative to the Cretaceous-Paleogene (K-Pg) boundary, we scored 4541 phenomic characters de novo for 86 fossil and living species. Combining these data with molecular sequences, we obta

Photographer: James Van Gundy Summary Author: James Van Gundy The Cretaceous-Paleogene (K-Pg) boundary, formerly known as the Cretaceous-Tertiary (K-T) boundary, was first described in terrestrial (non-marine) rocks at the above site on South Table Mountain in Golden, Colorado back in 1943. This boundary actually isn't visually well-defined here but was recognized on the basis of fossil. The K-Pg Boundary Fern Spike EventCompositionally, pollen samples recovered from $1 cm immediately above the K-Pg boundary are virtually devoid of K-taxa, but are also characterized by an unusually high abundance of fern spores, representing >70% of the assemblage (Figs. 9B and 10, Orth et al., 1981;Tschudy et al., 1984;Nichols, 1988, 1990;Nichols and Fleming, 1990;Wolfe, 1991) Thickening of the K-Pg boundary layer towards Chicxulub shows Chicxulub was the impact site. The significant changes in Earth's ecosystems all occur precisely at this boundary and thus, say the authors, a large asteroid impact into the sulfate-rich sediments at Chicxulub remains the most plausible cause for the K-Pg boundary mass extinction Mammals across the K/Pg boundary in northeastern Montana, U.S.A.: dental morphology and body-size patterns reveal extinction selectivity and immigrant-fueled ecospace filling - Volume 39 Issue However, some lines of evidence are inconsistent with SH. For instance, recent studies demonstrate that end-Cretaceous therians achieved greater ecomorphological diversity than previously realized [22-26], and mammals began a trend of increasing average body size 10-20 Myr before the K-Pg boundary [13,15,27].Multituberculates, a diverse clade of extinct non-therian mammals, experienced a.

Coesite Stishovite High Pressure Impact Material Himalayas

The K/Pg boundary was defined at the base of the boundary clay at a section near El Kef, Tunisia (Keller, 1998bMolina et al., 2006Molina et al., , 2009) Ecosystems response and restitution time across the K/Pg boundary transition at high-latitudes, Southern Hemisphere, New Zealand - a palynological approach Pi Willumsen and Vivi Vajda Department of Earth and Ecosystem Sciences, Division of Geology, Lund University, Sölvegatan 12, 223 62 Lund, Sweden Pi.Willumsen@geol.lu.s An integrated study of palynology, Mossbauer spectroscopy, mineralogy and osmium isotopes has led to the detection of the first K-Pg boundary clay layer in a Southern Hemisphere terrestrial setting. The K-Pg boundary layer was independently identified at centimetre resolution by all the above mentioned methods at the marine K-Pg boundary site of mid-Waipara and the terrestrial site of. Continue reading K-T Boundary Skip to content. Universe Today. Space and astronomy news. Posted on September 10, 2009 May 4, 2017 by Fraser Cain. K-T Boundary [/caption] What killed the dinosaurs Walter Alvarez and Alessandro Montanari at K Pg (KT) Boundary at Bottaccione Gorge near Gubbio Italy.jpg 4,000 × 3,000; 3.85 MB Geochronologist collecting ash.jpg 540 × 405; 95 KB K-T-boundary.JPG 2,274 × 1,913; 967 K

The K/Pg boundary is well exposed within the Crosswicks Creek basin in southern Monmouth County, New Jersey. It is represented by the uppermost Maastrichtian New Egypt Formation and Danian Hornerstown Formation K-T boundary layer at the Sussex locality. Top: boundary interval overlain by Tertiary coal and underlain by Cretaceous mudstone in outcrop, Bottom: detail image of boundary claystone. The thin dark layer at the top has the highest concentration of iridium Around the Cretaceous-Paleogene (K-Pg) boundary, an obvious global cooling occurred, which resulted in dramatic changes in terrestrial ecosystems and the evolutionary trends of numerous organisms. However, how plant lineages responded to the cooling has remained unknown until now. Between ca. 70-60 Ma Mesocyparis McIver & Basinger (Cupressaceae), an extinct conifer genus, was distributed.

Earth, 66 million years ago | Earth Blog

Each Sunday we present a notable item from our archives. This EPOD was originallypublished October 1, 2013.. Photographer: James Van Gundy Summary Author: James Van Gundy The Cretaceous-Paleogene (K-Pg) boundary, formerly known as the Cretaceous-Tertiary (K-T) boundary, was first described in terrestrial (non-marine) rocks at the above site on South Table Mountain in Golden, Colorado back in 1943 The K/Pg boundary is in the upper part of the transgressive systems tract, below a maximum flooding surface. Sequence stratigraphic analysis of a second section, Campo Pit, New Jersey, USA, showed that the K/Pg boundary occurs within a transgressive systems tract in New Jersey as well, suggesting a global sea-level rise across the K/Pg boundary The K-Pg boundary. Regarding Walker's assertions that the K-Pg impact materials may have separate (or even non-impact) sources, these issues have been thoroughly addressed in the geological literature. The unity of the debris is confirmed by many lines of evidence.

The boundary between the two? You guessed it: the K/Pg boundary, there marked by a coal seam containing some volcanic ash. We fell in love at the stratigraphic signal of the dinosaur's demise, and here was an opportunity to revisit that same moment in geological time, in a different country, in a different depositional setting Tjördis Störling: Changes in global ocean silica across the K/Pg boundary Javascript är avstängt eller blockerat i din webbläsare. Detta kan leda till att vissa delar av vår webbplats inte fungerar som de ska

We describe an outcrop of the Cretaceous-Paleogene (K-Pg) boundary exposed due to construction near New Albany, Union County, Mississippi. It consists of the Owl Creek Formation and overlying Clayton Formation. The Owl Creek Formation is rich in the ammonites Discoscaphites iris and Eubaculites carinatus, which, along with biostratigraphically important dinoflagellate cysts and calcareous. No matter how the scientific debate resolves, because the Hell Creek Formation is one of few places in the world where fossils can be found on both sides of the K-Pg boundary, the fossil collections Clemens made there in 40 years of excavation were critical to ground-truthing the impact hypothesis, said Patricia Holroyd, a vertebrate paleontologist and UCMP senior museum scientist A. iridium in K-Pg boundary clay B. glass spheres in K-Pg boundary rocks C. shocked quarts in K-Pg boundary clay D. All of the possible answers are correct. D. all of the possible answers are correct. Geologists believe that the impact of a 13-km-wide meteorite 65 million years ag The two waves of niche filling on either side of the K-Pg boundary coincide with, and might be linked to, changes in reef structure and climate. The Late Cretaceous is a 'greenhouse' interval lacking permanent icecaps at the poles [ 10 ]

THE K/PG BOUNDARY IN NEW JERSEY Recent work on the uppermost Cretaceous deposits in New Jersey has established that the stratigraphically highest lev-els of the Cretaceous are latest Maastrichtian [Landmanet al., 2004, 2007], and the K/Pg boundary ejecta layer has been located down dip in the subsurface in the Bass Rive The K-Pg Extinction. At the boundary between the Cretaceous (K) and Paleogene (Pg) Periods, ecosystems all around the world suffered major losses of species in a geologically short time period. This is called a mass extin ction, and the K-Pg event was one of history's worst The recent resolution on the K-Pg Boundary. Scientists resolve their differences on the death of the dinosaurs. Around 65.5 million years ago, 48% of the earth's genera suddenly became extinct. It is a phenomenon researchers extensively debated until 2010, when the scientific community came to an agreement

3 Places to see the K-Pg Big Bend Conservanc

The K/Pg boundary also marks the limit between the Mesozoic and Cenozoic Eras, between the Upper Cretaceous and Paleocene Epochs, as well as between the Maastrichtian and Danian Stages. It coincides with one of the five mass extinctions in Earth's history, whic K/Pg boundary. However, at least some of the variation appears to have also been caused by changes in the export dynamics of GDGTs. In particular, export of GDGTs from surface waters appears to have been adversely impacted, consistent with much evidence for disruption o The K-Pg boundary is also a physical boundary you can see in the stratigraphy (the rock layers) around the world. It is a layer that contains a lot of ash and iridium (an element that is rare on Earth and usually indicates an asteroid or meteorite impact) Krita-tertiär-gränsen, även K-T-gränsen, krita-paleogengränsen och K-Pg-gränsen, utgör gränsen mellan de två geologiska perioderna krita och paleogen.Gränsen uppkom för cirka 65,5 miljoner år sedan. Gränsen är i dag även känd som krita-paleogengränsen, eftersom tertiär inte längre är en officiell geologisk period enligt Gradstein 2004. Det som en gång var. The K-Pg boundary and the Chicxulub impact both date to slightly over 66 Ma (though older texts often use a date of 65 Ma). Scientific consensus holds that the Chicxulub impact was the primary cause of the mass extinction

Of dups and dinos: evolution at the K/Pg boundary

Thickening of the K-Pg boundary layer towards Chicxulub shows Chicxulub was the impact site. The significant changes in Earth's ecosystems all occur precisely at this boundary and thus, say the reviewers, a large asteroid impact into the sulfate-rich sediments at Chicxulub remains the most plausible cause for the K-Pg boundary mass extinction, the University of Texas said the K/Pg boundary, 44 species (72.13%) became extinct at the K/Pg boundary (Plate 1). The remaining 15 spe- cies (about 24.59%) represent the Cretaceous survivors in the Early Danian sediments, but disappear by 1 m above the K/Pg boundary in Zones P0 (Plate 1). This pattern supports the sudden catastrophic pattern of spe Subject: Re: K/Pg Boundary: How it Really Happened (cartoon) From: Mark Hallett <marksabercat@yahoo.com> Date: Tue, 2 Jun 2009 11:17:10 -0700 (PDT) Authentication-results: msg-ironport2.usc.edu; dkim=neutral (message not signed) header.i=none; Cc: dinosaur@usc.edu; Reply-to: marksabercat@yahoo.com; Sender: owner-DINOSAUR@usc.ed The K-Pg boundary is a thin band of rock that occurs between Cretaceous and Paleogene rocks. The Alvarez team found that it contained a high amount of iridium, a rare metal. One of the few places in which Iridium is found in similar quantities is in asteroids

The global vegetation pattern across the Cretaceous

Where the boundary is in marine sediments, the iridium occurs in a layer just above the last Cretaceous microfossils, and the sediments above it contain Paleocene microfossils from the earliest part of the Cenozoic. The iridium is present only in the boundary rocks and therefore was deposited in a single large spike: a very short event In an analysis of thousands of fossil pollen and leaves spanning the Cretaceous-Paleogene (K/Pg) boundary, researchers found that the cataclysmic asteroid impact that resulted in the destruction.

An Adventurous Life - Geology (U

One of the Big Five mass extinctions in the Phanerozoic Eon occurred at the Cretaceous-Paleogene (K-Pg) boundary (66.0 million years ago). The K-Pg mass extinction was triggered by a meteorite impact that produced a crater at Chicxulub on the Yucatán Peninsula, Mexico Focusing on well-sampled and temporally well-constrained mammalian faunas across the K/Pg boundary in northeastern Montana, I quantified dental-shape disparity and morphospace occupancy via landmark- and semilandmark-based geometric morphometrics and mean body size, body-size disparity, and body-size structure via body-mass estimates.My results. Boundaries and subdivisions. The K-Pg boundary that marks the separation between Cretaceous and Paleocene is visible in the geological record of much of the Earth by a discontinuity in the fossil fauna, with high iridium levels. There is also fossil evidence of abrupt changes in flora and fauna the K-Pg boundary. New iridium fluence data were calculated for all available K-Pg boundary profiles. All profiles with insufficient resolution to calculate accu-rate fluences (too few or too widely spaced samples) were discarded. These newly calculated high-quality iridium fluences vary by over two orders of magnitud

K/T BOUNDARY PHOTO - meteorite studie

The Cretaceous-Paleogene (K-Pg) boundary is associated with one of the most significant periods of biological turnover in Earth history. It corresponds to one of the three largest mass extinctions and is followed by a profound adaptive radiation of modern taxa, most notably mammals, in the Paleocene (Schulte et al., 2010; Halliday et al., 2017) The K/Pg extinction (or boundary event): K is the formal symbol for the Cretaceous, and Pg for the Paleogene The Cretaceous/Teritary extinction (or boundary event), or its abbreviation K/T: the Tertiary is the former name for the first Period of the Cenozoic Era; in modern stratigraphy the Tertiary is no longer used and instead we break it into the Paleogene and Neogene Periods

The Cretaceous-Palaeogene (K-Pg) boundary 65 million years ago (Ma) was a key episode in recent vertebrate history, marking the end of the dinosaur era and the rise of birds and mammals. This boundary is associated with mass extinctions resulting from an extraterrestrial impact and periods of flood-basalt volcanism [ 1 ], the biological consequences of which are still poorly understood and. K-Pg boundary sites, interca-lated between two layers rich in Chicxulub ejecta, suggests that the Chicxulub impact caused a col-lapse of the Yucatan carbonate platform and triggered mass flows and tsunamis in the Gulf of Mexico and adjacent areas (Fig. 2andfigs.S3toS8)(17, 18, 30) The K/Pg boundary is a highly-irregular hardground surface with many Thalassinoides burrows penetrating up to two meters below. Carbonate sands are directly above the boundary, with the clay layers of varying vertical distances but rarely sitting on the hardground. There are at least seven clays, with the largest (Layer D) several centimeters. South Caspian Basin supports a late Cenozoic Flood boundary. by Timothy L. Clarey and Davis J. Werner. Repeated claims since the mid-1990s have been made by some creation scientists that the K-Pg (Cretaceous-Paleogene) boundary marks the end of the Flood and the end of marine deposition across the continents. 1-4 Furthermore, they claim that the massive volumes of post-K-Pg sediments. Discovery of Iridium in the K-Pg Boundary Layer In the late 1970s, geologist Walter Alvarez was investigating the composition of the K-Pg boundary layer in different parts of the world. He asked his father, Nobel Prize-winning physicist Luis Alvarez, to help him analyze the elemental composition of the layer The K‐Pg boundary event bed at Hole U1403B offshore Newfoundland is characterized by the following geological, mineralogical, and geochemical features: It contains a spherule horizon of 0.5 cm thickness; this thickness, however, was expanded during the preparation by uptake of resin up to 1.8 cm

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