scholarly journals Belemnite phylogeny and decline during the mid-Cretaceous

2021 ◽  
Author(s):  
Kevin Stevens
Keyword(s):  
Early Cretaceous ◽  
Teleost Fish ◽  
Cladistic Analysis ◽  
Early Jurassic ◽  
Fish Diversity ◽  
Widespread Distribution ◽  
Oceanic Anoxia ◽  
Stratigraphic Range

Belemnites are common fossil coleoid cephalopods of the Mesozoic. They began to diversify in the Triassic-Early Jurassic and maintained this diversity until the early Early Cretaceous. During the mid-Cretaceous, they declined in diversity and distribution, being restricted to only the Boreal and Austral Realm since the Turonian. Here, I present the first cladistic analysis of belemnite phylogeny, spanning taxa representative of the whole diversity and stratigraphic range of the group. This analysis shows that the usually applied subdivision of all belemnites into "Belemnitina" and "Belemnopseina" is not supported. A newly identified clade, the Pseudoalveolata, is suggested here. Pseudoalveolate belemnites represent the last remaining belemnites after the Aptian. Oceanic anoxia and warming are likely the main cause of the mid- Cretaceous belemnite decline, resulting in the Aptian-Albian dominance of the warm-adapted pseudoalveolate genus Neohibolites. The rise of teleost fish diversity during the mid- Cretaceous is discussed and its relevance for belemnite evolution. Some teleosts (e.g., Enchodus) might have taken over the mesopredator niches left by belemnites during the mid- Cretaceous, being better adapted to warming seas. Belemnites were not able to recover their earlier widespread distribution and diversity and the last remaining, disjunctly distributed families, the northern Belemnitellidae and southern Dimitobelidae, became extinct at the K/Pg-boundary.

Mesozoic Tectonic Setting of SE Sundaland After Magmatism and Suture Evidences in JS-1 Ridge Area

2021 ◽  
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
Tectonic Setting ◽  
Plate Boundary ◽  
Early Jurassic ◽  
The South ◽  
Magmatic Arc ◽  
Plate Convergence ◽  
Ridge Area ◽  
Cretaceous Subduction

Mesozoic plate convergence in SE Sundaland has been a source of debate for decades. A determination of plate convergence boundaries and timing have been explained in many publications, but not all boundaries were associated with magmatism. Through integration of both plate configurations and magmatic deposits, the basement can be accurately characterized over time and areal extents. This paper will discuss Cretaceous subductions and magmatic arc trends in SE Sundaland area with additional evidence found in JS-1 Ridge. At least three subduction trends are captured during the Mesozoic in the study area: 1) Early Jurassic – Early Cretaceous trend of Meratus, 2) Early Cretaceous trend of Bantimala and 3) Late Cretaceous trend in the southernmost study area. The Early Jurassic – Early Cretaceous subduction occurred along the South and East boundary of Sundaland (SW Borneo terrane) and passes through the Meratus area. The Early Cretaceous subduction occurred along South and East boundary of Sundaland (SW Borneo and Paternoster terranes) and pass through the Bantimala area. The Late Cretaceous subduction occurred along South and East boundary of Sundaland (SW Borneo, Paternoster and SE Java – South Sulawesi terranes), but is slightly shifted to the South approaching the Oligocene – Recent subduction zone. Magmatic arc trends can also be generally grouped into three periods, with each period corresponds to the subduction processes at the time. The first magmatic arc (Early Jurassic – Early Cretaceous) is present in core of SW Borneo terrane and partly produces the Schwaner Magmatism. The second Cretaceous magmatic arc (Early Cretaceous) trend is present in the SW Borneo terrane but is slightly shifted southeastward It is responsible for magmatism in North Java offshore, northern JS-1 Ridge and Meratus areas. The third magmatic arc trend is formed by Late Cretaceous volcanic rocks in Luk Ulo, the southern JS-1 Ridge and the eastern Makassar Strait areas. These all occur during the same time within the Cretaceous magmatic arc. Though a mélange rock sample has not been found in JS-1 Ridge area, there is evidence of an accretionary prism in the area as evidenced by the geometry observed on a new 3D seismic dataset. Based on the structural trend of Meratus (NNE-SSW) coupled with the regional plate boundary understanding, this suggests that both Meratus & JS-1 Ridge are part of the same suture zone between SW Borneo and Paternoster terranes. The gradual age transition observed in the JS-1 Ridge area suggests a southward shift of the magmatic arc during Early Cretaceous to Late Cretaceous times.

A new eucryptodiran turtle from the Early Cretaceous Jiufotang Formation of western Liaoning, China

Zootaxa ◽  
2010 ◽  
Vol 2676 (1) ◽  
pp. 45 ◽  
Author(s):  
CHANG-FU ZHOU
Keyword(s):  
Early Cretaceous ◽  
Cladistic Analysis ◽  
Yixian Formation ◽  
Liaoning Province ◽  
Jehol Biota ◽  
Western Liaoning ◽  
The Third

A new eucryptodiran turtle from the Jiufotang Formation of Lamadong, Jianchang County, represents the third turtle taxon, Liaochelys jianchangensis gen. et sp. nov., from the Jehol Biota of western Liaoning Province, China. This taxon is diagnosed by a character combination including a midline contact of the prefrontals, vertebrals wider than long, third costals strongly expanded distally, and a medial contact of the eighth costals. A preliminary cladistic analysis places Liaochelys jianchangensis along the phylogenetic stem of Cryptodira in a position more derived than the taxa, Manchurochelys manchoukuoensis and Ordosemys liaoxiensis, known from the underlying Yixian Formation. This discovery opens a new window into the osteology and evolution of primitive eucryptodiran turtles.

EARLY CRETACEOUS TETRADS, ZONASULCULATE POLLEN, AND WINTERACEAE. II. CLADISTIC ANALYSIS AND IMPLICATIONS

1990 ◽  
Vol 77 (12) ◽  
pp. 1558-1568 ◽  
Author(s):  
James A. Doyle ◽  
Carol L. Hotton ◽  
Jerome V. Ward
Keyword(s):  
Early Cretaceous ◽  
Cladistic Analysis

Substantial vegetation response to Early Jurassic global warming with impacts on oceanic anoxia

2019 ◽  
Vol 12 (6) ◽  
pp. 462-467 ◽  
Author(s):  
Sam M. Slater ◽  
Richard J. Twitchett ◽  
Silvia Danise ◽  
Vivi Vajda
Keyword(s):  
Global Warming ◽  
Early Jurassic ◽  
Vegetation Response ◽  
Oceanic Anoxia

scholarly journals The tectonic significance of the Early Cretaceous forearc-metamorphic assemblage in south-central Alaska based on detrital zircon U–Pb dating of sedimentary protoliths

2015 ◽  
Vol 52 (12) ◽  
pp. 1182-1190 ◽  
Author(s):  
Amanda Labrado ◽  
Terry L. Pavlis ◽  
Jeffrey M. Amato ◽  
Erik M. Day
Keyword(s):  
Early Cretaceous ◽  
Detrital Zircon ◽  
Early Jurassic ◽  
Ductile Deformation ◽  
Metamorphic Rocks ◽  
Accretionary Complex ◽  
Metamorphic Complex ◽  
Metasedimentary Rocks ◽  
South Central ◽  
Detrital Zircon Ages

A complex array of faulted arc rocks and variably metamorphosed forearc accretionary complex rocks form a mappable arc–forearc boundary in southern Alaska known as the Border Ranges fault (BRF). We use detrital U–Pb zircon dating of metasedimentary rocks within the Knik River terrane in the western Chugach Mountains to show that a belt of Early Cretaceous amphibolite-facies metamorphic rocks along the BRF was formed when older mélange rocks of the Chugach accretionary complex were reworked in a sinistral-oblique thrust reactivation of the BRF during a period of forearc plutonism. The metamorphic subterrane of the Knik River terrane has a maximum depositional age (MDA) of 156.5 ± 1.5 Ma and a detrital zircon age spectrum that is indistinguishable from the Potter Creek assemblage of the Chugach accretionary complex, supporting correlation of these units. These ages contrast strongly with new and existing data that show Triassic to earliest Jurassic detrital zircon ages from metamorphic screens in the plutonic subterrane of the Knik River terrane, a fragmented Early Jurassic plutonic assemblage generally interpreted as the basement of the Peninsular terrane. Based on these findings, we propose the following new terminology for the Knik River terrane: (1) “Carpenter Creek metamorphic complex” for the Early Cretaceous “metamorphic subterrane”, (2) “western Chugach trondhjemite suite” for the Early Cretaceous forearc plutons within the belt, (3) “Friday Creek assemblage” for a transitional mélange unit that contains blocks of the Carpenter Creek complex in a chert–argillite matrix, and (4) “Knik River metamorphic complex” in reference to metamorphic rocks engulfed by Early Jurassic plutons of the Peninsular terrane that represent the roots of the Talkeetna arc. The correlation of the Carpenter Creek metamorphic complex with the Chugach mélange indicates that the trace of the BRF lies ∼1–5 km north of the map trace shown on geologic maps, although, like other segments of the BRF, this boundary is blurred by local complexities within the BRF system. Ductile deformation of the mélange is sufficiently intense that few vestiges of its original mélange fabric exist, suggesting the scarcity of rocks described as mélange in the cores of many orogens may result from misidentification of rocks that have been intensely overprinted by younger, ductile deformation.

What Iberian dinosaurs reveal about the bridge said to exist between Gondwana and Laurasia in the Early Cretaceous

2009 ◽  
Vol 180 (1) ◽  
pp. 5-11 ◽  
Author(s):  
José Ignacio Canudo ◽  
José Luis Barco ◽  
Xabier Pereda-Suberbiola ◽  
José Ignacio Ruiz-Omeñaca ◽  
Leonardo Salgado ◽  
...  
Keyword(s):  
Iberian Peninsula ◽  
Northern Hemisphere ◽  
Early Cretaceous ◽  
Late Jurassic ◽  
Open Ocean ◽  
Early Jurassic ◽  
Place Of Origin ◽  
Iberian Margin ◽  
Great Development ◽  
Iberian Plate

Abstract Some Cretaceous dinosaur taxa with a broad enough record on the continents of the northern hemisphere (Laurasia) or in the southern continents (Gondwana) have been interpreted as Laurasian or Gondwanan in origin. The occasional presence of these taxa outside Laurasia or Gondwana respectively has frequently been explained in terms of dispersal from their place of origin by means of land bridges that are indeterminate in location and character. One example of such a dispersal event is provided by the Early Cretaceous dinosaurs of Europe and Africa. Certain European taxa have been interpreted as having their origin in Gondwana. If we regard these presences common to both areas as being the result of a point of communication between Laurasia and western Gondwana or at least of sporadic flows in both directions during the Early Cretaceous, we may opt for dispersal as an explanation. It has been assumed that there was an intercontinental bridge between Africa and Europe passing through the archipelago of which Iberia formed a part. This interpretation emerged from the idea that such a bridge existed in the Late Jurassic, explaining the presence of similar ornithopod dinosaurs in Africa and Europe. However, from the end of the Early Jurassic a period of “rift” began on the southern Iberian margin, entailing the formation of a sedimentary furrow with pelagic sedimentation in what is known as the Subbetic zone. Moreover, the differences in the observed dinosaur fauna between western Gondwana and the Iberian Peninsula in the Neocomian can be explained as the result of endemism and regional extinctions. The archipelago that formed the Iberian plate was Laurasia’s closest continental mass to Gondwana during the Neocomian, yet there was still a separation of several hundred kilometres of open ocean without islands. Such a barrier would seem difficult for dinosaurs to overcome. As such, we lack proof of communication between the two supercontinents via Iberia during the Neocomian. The situation appears to change in the Barremian-Aptian transition. Some of the taxa present in the Hauterivian-Barremian of Europe are recorded in Gondwana from the Aptian onwards. This can possibly be explained in terms of the more complete record that exists, but it cannot be ruled out that a communication was established between Gondwana and Laurasia at the end of the Barremian. For the time being, we lack geological support for this bridge in Iberia, yet it might be located in Apulia, where there is a great development of shallow-shelf carbonates with dinosaur remains from the period in question.

scholarly journals Physical and chemical conditions of basaltic magmatism of archipelago Franz Josef Land

2019 ◽  
Vol 64 (7) ◽  
pp. 700-725
Author(s):  
V. A. Simonov ◽  
Yu. V. Karyakin ◽  
A. V. Kotlyarov
Keyword(s):  
Early Cretaceous ◽  
Melt Inclusions ◽  
Early Jurassic ◽  
Chemical Compositions ◽  
Tholeiitic Magma ◽  
Basaltic Magmatism ◽  
Franz Josef Land ◽  
Chemical Conditions ◽  
Deep Sources ◽  
Physical And Chemical

As a result of mineralogical and thermobarogeochemical researches of different-age basaltic complexes of Archipelago Franz Josef Land (FJL) regular changes in time of compositions of plagioclases, clinopyroxenes and melt inclusions are established. Chemical compositions of inclusions directly testify to prevalence in Early Jurassic of plateau basaltic melts similar (according to the content of the basic components, and also trace and rare-earth elements) to typical basalt tholeiitic magma of the Siberian platform. In Early Cretaceous melts already had the enriched subalkaline character. Calculations of conditions of magma generation, spent on the basis of the data on melt inclusions, have shown evolution from Early Jurassic to Early Cretaceous (with allocation of three peaks of magmatic activity: 192.2±2.8, 157.4±3.5 and 131.5±0.8 million years) depths and temperatures (accordingly: 70-110 km and to 120 km, 1430-1580°С; 60-110 km, 1390-1580°С; 50-140 km, 1350-1690°С) of mantle melting with formation of deep sources of the FJL magmas.

scholarly journals Mesozoic Intracontinental Orogeny in the Tectonic History of the Kolyvan’– Tomsk Folded Zone (Southern Siberia): a Synthesis of Geological Data and results of Apatite Fission Track Analysis

2021 ◽  
Vol 62 (9) ◽  
pp. 1006-1020
Author(s):  
F.I. Zhimulev ◽  
E.V. Vetrov ◽  
I.S. Novikov ◽  
G. Van Ranst ◽  
S. Nachtergaele ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
Fission Track ◽  
Early Jurassic ◽  
Late Triassic ◽  
Apatite Fission Track ◽  
History Of ◽  
Paleozoic Rocks ◽  
Orogenic Events

Abstract —The Kolyvan’–Tomsk folded zone (KTFZ) is a late Permian collisional orogen in the northwestern section of the Central Asian Orogenic Belt. The Mesozoic history of the KTFZ area includes Late Triassic–Early Jurassic and Late Jurassic–Early Cretaceous orogenic events. The earlier event produced narrow deep half-ramp basins filled with Early–Middle Jurassic molasse south of the KTFZ, and the later activity rejuvenated the Tomsk thrust fault, whereby the KTFZ Paleozoic rocks were thrust over the Early–Middle Jurassic basin sediments. The Mesozoic orogenic events induced erosion and the ensuing exposure of granitoids (Barlak complex) that were emplaced in a within-plate context after the Permian collisional orogeny. Both events were most likely associated with ocean closure, i.e., the Paleothetys Ocean in the Late Triassic–Early Jurassic and the Mongol–Okhotsk Ocean in the Late Jurassic–Early Cretaceous. The apatite fission track (AFT) ages of granitoids from the Ob’ complex in the KTFZ range between ~120 and 100 Ma (the Aptian and the Albian). The rocks with Early Cretaceous AFT ages were exhumed as a result of denudation and peneplanation of the Early Cretaceous orogeny, which produced a vast Late Cretaceous–Paleogene planation surface. The tectonic pattern of the two orogenic events, although being different in details, generally inherited the late Paleozoic primary collisional structure of the Kolyvan’–Tomsk zone.

scholarly journals Earwigs (Dermaptera) from the Mesozoic of England and Australia, described from isolated tegmina, including the first species to be named from the Triassic

2016 ◽  
Vol 107 (2-3) ◽  
pp. 129-143 ◽  
Author(s):  
Richard S. Kelly ◽  
Andrew J. Ross ◽  
Edmund A. Jarzembowski
Keyword(s):  
New Taxa ◽  
Early Cretaceous ◽  
Early Jurassic ◽  
Late Triassic ◽  
Incertae Sedis ◽  
The Family

ABSTRACTDermaptera (earwigs) are described from the Triassic of Australia and England, and from the Jurassic and Cretaceous of England. Phanerogramma heeri (Giebel) is transferred from Coleoptera and it and Brevicula gradus Whalley are re-described. Seven new taxa are named based on tegmina: Phanerogramma australis sp. nov. and P. dunstani sp. nov. from the Late Triassic of Australia; P. gouldsbroughi sp. nov. from the Triassic/Jurassic of England; Brevicula maculata sp. nov. and Trivenapteron moorei gen. et sp. nov. from the Early Jurassic of England; and Dimapteron corami gen et sp. nov. and Valdopteron woodi gen. et sp. nov. from the Early Cretaceous of England. Phanerogramma, Dimapteron and Valdopteron are tentatively placed in the family Dermapteridae, and Trivenapteron is incertae sedis. Most of the specimens of Phanerogramma heeri are from the Brodie Collection and labelled ‘Lower Lias'; however, some were collected from the underlying Penarth Group, thus this species spans the Triassic/Jurassic boundary. The palaeobiogeography of the Late Triassic and Early Jurassic of England is discussed.

scholarly journals New semionotiform (Neopterygii) from the Tlayúa Quarry (Early Cretaceous, Albian), Mexico

Zootaxa ◽  
2011 ◽  
Vol 2749 (1) ◽  
pp. 1 ◽  
Author(s):  
ADRIANA LÓPEZ-ARBARELLO ◽  
JESÚS ALVARADO-ORTEGA
Keyword(s):  
North America ◽  
Early Cretaceous ◽  
Early Jurassic ◽  
Central Mexico ◽  
New Taxon ◽  
Ventral Border

We describe a new semionotiform fish, Tlayuamichin itztli gen. et sp. nov. from the Early Cretaceous (Albian) of Mexico, which constitutes one of the youngest semionotid articulated remains. The new taxon is represented by five well-preserved specimens from the Tlayúa Quarry near Tepexi de Rodríguez in Puebla State, central Mexico. A series of paraethmoid bones anterior to the supraorbital series, supraorbital bones extending beyond the anterior rim of the orbit, the presence of a large pentagonal supraorbital closing the anterior rim of the orbit, seven anterior infraorbitals, dorsally expanded infraorbitals at the ventral border of the orbit, and the most dorsal suborbital separating the preoperculum from the dermopterotic are potential autapomorphic features of the new taxon. The very long frontals, a dermopterotic that does not contact the anterodorsal corner of the operculum and the presence of a modified pectoral scale are additional features that help to diagnose the taxon. Tlayuamichin itztli gen. et sp. nov. resembles most closely “Lepidotes” minor from the Middle Purbeck Beds (early Berriasian), England. These two taxa share similarity with other species of Semionotus from the Early Jurassic of North America and the Triassic of Europe, suggesting interesting biogeographic relationships.

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