Grossplots: a Method for Estimating the Temperature State of the Earth and of Australia, Cretaceous to Middle Miocene

1997 ◽  
Vol 45 (3) ◽  
pp. 359 ◽  
Author(s):  
L. A. Frakes
Keyword(s):  
Middle Miocene ◽  
Global Climate ◽  
Interval Data ◽  
Late Eocene ◽  
Space Distribution ◽  
Mean Annual Temperature ◽  
The North ◽  
Early Oligocene ◽  
Time Space ◽  
Temperature State

Grossplots are compilations of globally distributed palaeotemperature data onto latitude versus age plots, which are then contoured. The results specifically show the distribution of temperature over the globe and its variations over the Cretaceous to Middle Miocene interval. Data for continents and oceans are plotted separately in this investigation, and each such grossplot is in accord with the known climate changes of this time. The general scarcity of quantitative palaeotemperature information for Australia can be rectified by deriving, from the global continental grossplot, the relationship between mean annual temperature and latitude. When these are applied to the latitude band progressively occupied by Australia, the following observations can be made: (1) during the Early Cretaceous, the south-east of the continent was subjected to freezing wintertime temperatures; (2) peak warming of northern Australia was attained in the Turonian–Santonian, but this was followed by cooling later in the Cretaceous; (3) Early Tertiary warming until the Late Eocene particularly affected the northern half of the continent, but this region then underwent the most severe cooling in the Early Oligocene; (4) subsequently, the whole of the continent cooled uniformly from conditions only slightly warmer than at present. Despite Australia’s equatorward march, the Late Cretaceous to Palaeocene climates of the continent have been influenced more effectively by changes in the global climate state. However, global cooling since the Eocene has been less effective than drift in controlling the warming climate of Australia. The time–space distribution of precipitation over Australia is estimated from the global relationship between terrestrial temperature and rainfall. The Eocene experienced the heaviest rainfall (> 1560 mm year-1, in the north only), and the Eocene to Middle Miocene experienced moderately high rates (> 500 mm year-1 in the northern three-quarters of the continent). Tertiary brown coals in southern regions were formed in proximity to areas of high rainfall. Continentwide low rates (< 500 mm year-1; semi-arid) are suggested for the Cretaceous, except for wet conditions in the north during the Albian–Santonian and the Late Maastrichtian. Estimates of precipitation are subject to factors such as continentality and location of moisture sources, which cannot be evaluated at present.

Evolutionary adaptation and geographic spread of the Cenozoic buccinid genus Lirabuccinum in the North Pacific

2003 ◽  
Vol 77 (5) ◽  
pp. 863-872 ◽  
Author(s):  
Kazutaka Amano ◽  
Geerat J. Vermeij
Keyword(s):  
North Pacific ◽  
Middle Miocene ◽  
Eastern Pacific ◽  
Early Pleistocene ◽  
Northwestern Pacific ◽  
The North ◽  
Early Oligocene ◽  
Rocky Bottom ◽  
Late Middle Miocene ◽  
The Western Pacific

The Early Oligocene to Recent genus Lirabuccinum Vermeij, 1991, is a North Pacific clade of rocky-bottom predatory buccinid gastropods. A re-examination of all available material from eastern Asia and comparison of this material with western American species leads us to recognize four northwestern Pacific species: L. fuscolabiatum (Smith, 1875) from the Pliocene to Recent; L. japonicum (Yokoyama, 1926) from the Pliocene and Early Pleistocene; L. branneri (Clark and Arnold, 1923) from the early Middle Miocene, also known from the Oligocene in the eastern Pacific; and Lirabuccinum sp. from the late Middle Miocene. The genus originated in the eastern Pacific and subsequently spread to the western Pacific by late Early Miocene to early Middle Miocene time. Lirabuccinum exemplifies a common pattern among rocky-bottom North Pacific gastropods in that the early species have a thick, internally strongly ribbed or denticulate outer lip. As they adapted to the colder boreal realm during the Pliocene and Pleistocene, Lirabuccinum and such other clades as Nucella, Ceratostoma, and Ocinebrellus (all Muricidae) evolved thinner, less heavily reinforced outer lips.

Pre-Priabonian Palaeogene formations in southwestern Bulgaria and northern Greece: stratigraphy and tectonic implications

1998 ◽  
Vol 135 (1) ◽  
pp. 101-119 ◽  
Author(s):  
IVAN S. ZAGORCHEV
Keyword(s):  
Late Cretaceous ◽  
Middle Eocene ◽  
Regional Metamorphism ◽  
Late Eocene ◽  
Thin Layers ◽  
The South ◽  
Northern Greece ◽  
The North ◽  
Early Oligocene ◽  
Metamorphic Core

The Paril Formation (South Pirin and Slavyanka Mountains, southwestern Bulgaria) and the Prodromos Formation (Orvilos and Menikion Mountains, northern Greece) consist of breccia and olistostrome built up predominantly of marble fragments from the Precambrian Dobrostan Marble Formation (Bulgaria) and its equivalent Bos-Dag Marble Formation (Greece). The breccia and olistostrome are interbedded with thin layers of calcarenites (with occasional marble pebbles), siltstones, sandstones and limestones. The Paril and Prodromos formations unconformably cover the Precambrian marbles, and are themselves covered unconformably by Miocene and Pliocene sediments (Nevrokop Formation). The rocks of the Paril Formation are intruded by the Palaeogene (Late Eocene–Early Oligocene) Teshovo granitoid pluton, and are deformed and preserved in the two limbs of a Palaeogene anticline cored by the Teshovo pluton (Teshovo anticline). The Palaeocene–Middle Eocene age of the formations is based on these contact relations, and on occasional finds of Tertiary pollen, as well as on correlations with similar formations of the Laki (Kroumovgrad) Group throughout the Rhodope region.The presence of Palaeogene sediments within the pre-Palaeogene Pirin–Pangaion structural zone invalidates the concept of a ‘Rhodope metamorphic core complex’ that supposedly has undergone Palaeogene amphibolite-facies regional metamorphism, and afterwards has been exhumed by rapid crustal extension in Late Oligocene–Miocene times along a regional detachment surface. Other Palaeogene formations of pre-Priabonian (Middle Eocene and/or Bartonian) or earliest Priabonian age occur at the base of the Palaeogene sections in the Mesta graben complex (Dobrinishka Formation) and the Padesh basin (Souhostrel and Komatinitsa formations). The deposition of coarse continental sediments grading into marine formations (Laki or Kroumovgrad Group) in the Rhodope region at the beginning of the Palaeogene Period marks the first intense fragmentation of the mid- to late Cretaceous orogen, in particular, of the thickened body of the Morava-Rhodope structural zone situated to the south of the Srednogorie zone. The Srednogorie zone itself was folded and uplifted in Late Cretaceous time, thus dividing Palaeocene–Middle Eocene flysch of the Louda Kamchiya trough to the north, from the newly formed East Rhodope–West Thrace depression to the south.

scholarly journals The Tectonic Evolution of Interior Oman

GeoArabia ◽  
1996 ◽  
Vol 1 (1) ◽  
pp. 28-51 ◽  
Author(s):  
Ramon J.H. Loosveld ◽  
Andy Bell ◽  
Jos J.M. Terken
Keyword(s):  
Sedimentary Basins ◽  
Late Eocene ◽  
Indian Plate ◽  
Arabian Plate ◽  
Time Interval ◽  
Passive Margins ◽  
The North ◽  
Hydrocarbon Traps ◽  
Early Oligocene ◽  
Sea Floor Spreading

ABSTRACT The evolution of Oman’s onshore sedimentary basins from the Late Precambrian to the Present is reflected by six tectono-stratigraphic units. Unit I, the Precambrian basement, represents continental accretion. Units II and III, Infracambrian to Ordovician, may reflect two periods of rifting, possibly related to Najd movements in western Saudi Arabia. The northeast-southwest trending salt basins formed during this time interval. A classical “steer’s head” basin geometry is developed in North Oman, whereas a less complete rift-sag sequence is preserved in South Oman. Of the entire time-span from Late Silurian to Mid-Carboniferous, only little Devonian (Emsian) sediment is preserved. Unit IV, Late Carboniferous to Mid-Cretaceous, reflects the break-up of Gondwana and the creation of the northeastern and southeastern passive margins of the Arabian Plate. Unit V documents intra-plate deformation related to Late Cretaceous continent-ocean obduction in the north and transpressional movements of the Indian Plate in the east. Unit VI, spanning the Tertiary, represents a return to quiet conditions followed by continent-continent collision in the north. Following Late Eocene uplift, the Gulf of Aden rift developed in the south in the early Oligocene, with sea-floor spreading from the Late Miocene onwards. Salt flow and dissolution, both playing a major role in the configuration of most intra- and post-salt hydrocarbon traps in Oman, are episodic and can be related to tectonic events.

Tertiary extension and tilting in the Queen Charlotte Islands, evidence from dyke swarms and their paleomagnetism

1992 ◽  
Vol 29 (9) ◽  
pp. 1878-1898 ◽  
Author(s):  
E. Irving ◽  
J. G. Souther ◽  
J. Baker
Keyword(s):  
North American ◽  
Late Eocene ◽  
North American Plate ◽  
Western Margin ◽  
Queen Charlotte Islands ◽  
The North ◽  
Early Oligocene ◽  
Magnetic Stability ◽  
Transform Margin ◽  
Dyke Swarms

The Queen Charlotte Islands form the western margin of the Tertiary Queen Charlotte Basin, which is situated on the western margin of the North American Plate. They contain seven major dyke swarms of Late Eocene to Miocene age, a period when the relative motions of the Pacific and the North American plates in this region were dominantly dextral strike slip (transform margin), with intervals of highly oblique divergence and convergence. Within each swarm, dykes have a systematic trend. However, trends vary from swarm to swarm, indicating that the stress field varied. A total of 678 cores (1352 specimens) were collected from 129 dykes in six swarms over a distance of about 200 km. Magnetic stability is variable. One hundred and one dykes yielded records of the paleofield. Data are also reported from an Oligocene pluton (5 sites, 27 cores, 52 specimens) and Miocene lavas (8 sites, 52 cores, 101 specimens). Both normal and reversed magnetizations occur, but irrespective of sign, the mean directions of remanent magnetization of each swarm and of the pluton and the lavas have systematically steeper inclinations than the value calculated from coeval rocks in North America. To explain this it is proposed that, after dyke emplacement, the sampling areas were tilted to the north or northwest by amounts that vary between 9 and 16°. Apparently, crustal tilting, similar in magnitude and direction, extended over distances of approximately 200 km. This cannot reflect tilting of a single block. Instead, it is argued that at least the southern Queen Charlotte Islands underwent considerable northerly or north-northwesterly directed extension and normal block faulting, which followed and in part was concurrent with the formation of widespread mid-Tertiary dyke swarms, plutons and lava flows. Making use of the fact that dykes propagate perpendicular to the direction of extension, and combining previously measured dyke orientations with paleomagnetic data, three stages of extension are proposed: east–west extension sometime during the Late Eocene to Early Oligocene; north–south extension sometime in the interval Late Oligocene to Early Miocene; and northwest–southeast extension sometime during Late Miocene or later time.

Symplocos Fruits from the Pliocene of Colombia

2021 ◽  
Vol 46 (2) ◽  
pp. 416-421
Author(s):  
Steven R. Manchester ◽  
Terry A. Lott ◽  
Fabiany Herrera ◽  
Henry Hooghiemstra ◽  
Vincent M. Wijninga ◽  
...  
Keyword(s):  
North America ◽  
South America ◽  
Middle Miocene ◽  
Late Eocene ◽  
The North ◽  
Extant Species ◽  
Molecular Phylogenetic ◽  
Voucher Specimens ◽  
Molecular Phylogenetic Data ◽  
Key Characters

Abstract— Fossil fruits of Symplocos (Ericales: Symplocaceae) are here recognized from the Pliocene of Guasca, Colombia, based on specimens formerly attributed to Cordia (Cordiaceae, Boraginales). Symplocos vera (Berry) comb. nov. is represented by 19 lignitized fruits. The fossils are recognized as belonging to Symplocos primarily by their woody endocarps that are apically truncate and that possess 3 to 5 apical germination pores and locules, and a central vascular canal extending the length of the endocarp. In several key characters they are highly congruent with the endocarps of the extant Neotropical clade S. ser. Symplocos. Some of the extant species in the series are variably 3- to 5-locular; 4-locular endocarps are otherwise rare in Symplocos, and 5-locular endocarps appear to be unique to this series. Symplocos vera is the only specifically named record of fossil Symplocos fruits with accessible voucher specimens from South America. The younger Neogene age of the fossils relative to those attributed to S. ser. Symplocos from the late Eocene of Texas, along with a report of Colombian fossil endocarps from the middle Miocene, supports the North America to South America migration inferred for this clade from molecular phylogenetic data.

scholarly journals Turbidite Fasies of Lower Penosogan Formation in Karanggayam Area, Kebumen, Indonesia

2018 ◽  
Vol 12 (6) ◽  
pp. 124
Author(s):  
Yan Rizal ◽  
Wahyu Dwijo Santoso ◽  
Alfend Rudyawan ◽  
Romy Ari Setiaji ◽  
Eko Bayu Purwasatriya
Keyword(s):  
Depositional Environment ◽  
Middle Miocene ◽  
Global Climate ◽  
Tectonic Activity ◽  
The North ◽  
Central Java ◽  
Clastic Sedimentary Rock ◽  
Clastic Sedimentary ◽  
Crevasse Splay ◽  
Bottom To Top

A continuous clastic sedimentary rock outcrop in the Karanggayam Area, Kebumen represents the complete deep marine fan facies of the Middle Miocene Lower Penosogan Formation. Lithology association and vertical succession were observed from a 63 meters detailed measured section along the Karanggayam River. This study aims to identify and classify the turbidite succession as well as the depositional environment of the formation within the North Serayu Basin, Central Java.      From the bottom to top the Lower Penosogan Formation is divided into: A2, B2, C2, D2 and F2 facies which represents basin plain, overbank (levee and distal levee), crevasse splay, channel-fill and frontal splay facies respectively. Changes in the depositional environment are interpreted to be influenced by the dynamic changes in morphology and global climate change caused by underwater volcanic activity as a result of Middle Miocene tectonic activity. 

scholarly journals Links between CO<sub>2</sub>, glaciation and water flow: reconciling the Cenozoic history of the Antarctic Circumpolar Current

2014 ◽  
Vol 10 (6) ◽  
pp. 1957-1966 ◽  
Author(s):  
J.-B. Ladant ◽  
Y. Donnadieu ◽  
C. Dumas
Keyword(s):  
Antarctic Circumpolar Current ◽  
Middle Miocene ◽  
Ice Sheet ◽  
Late Eocene ◽  
Early Oligocene ◽  
History Of ◽  
Potential Impact ◽  
Circumpolar Current ◽  
The Antarctic ◽  
Exact Timing

Abstract. The timing of the onset of the Antarctic Circumpolar Current (ACC) is a crucial event of the Cenozoic because of its cooling and isolating effect over Antarctica. It is intimately related to the glaciations occurring throughout the Cenozoic from the Eocene–Oligocene (EO) transition (&amp;approx; 34 Ma) to the middle Miocene glaciations (&amp;approx; 13.9 Ma). However, the exact timing of the onset remains debated, with evidence for a late Eocene setup contradicting other data pointing to an occurrence closer to the Oligocene–Miocene (OM) boundary. In this study, we show the potential impact of the Antarctic ice sheet on the initiation of a strong proto-ACC at the EO boundary. Our results reveal that the regional cooling effect of the ice sheet increases sea ice formation, which disrupts the meridional density gradient in the Southern Ocean and leads to the onset of a circumpolar current and its progressive strengthening. We also suggest that subsequent variations in atmospheric CO2, ice sheet volumes and tectonic reorganizations may have affected the ACC intensity after the Eocene–Oligocene transition. This allows us to build a hypothesis for the Cenozoic evolution of the Antarctic Circumpolar Current that may provide an explanation for the second initiation of the ACC at the Oligocene–Miocene boundary while reconciling evidence supporting both early Oligocene and early Miocene onset of the ACC.

scholarly journals Paleoecology of Late Eocene-Oligocene foraminiferal assemblages in a two-well transect across the North-East Newfoundland shelf

1991 ◽  
Vol 10 (1) ◽  
pp. 57-67
Author(s):  
F. C. Thomas
Keyword(s):  
North Sea ◽  
Late Eocene ◽  
Western Boundary ◽  
Late Oligocene ◽  
North East ◽  
The North ◽  
Early Oligocene ◽  
The North Sea ◽  
Relationship Of ◽  
The Relationship

Abstract. Core samples from the Paleogene of the Bonavista C-99 well on the northeast Newfoundland shelf and cuttings from downdip Blue H-28 contain foraminiferal assemblages which enable reconstruction of paleoenvironments along a downslope transect in Eocene through Late Oligocene-Miocene time. Comparison with coeval assemblages in North Sea wells with respect to structure and grain size of agglutinated taxa between the two areas reveal inter-basin differences.Reconstruction of the paleobathymetry derived from foraminiferal analysis, confirms seismic evidence for shallowing at the Bonavista site beginning in the Early Oligocene. The relationship of the Bonavista assemblages to contour currents is explored with reference to modern regional analogues. Species such as Reticulophragmium amplectens, Haplophragmoides walteri, Eponides umbonatus and Uvigerina ex. gr. miozea-nuttalli persist stratigraphically higher in the deeper Blue site.The paleoslope of this two-well transect is determined as approximately 0.48° during the Middle to Late Eocene and 0.68° during the Late Oligocene-Early Miocene. The bottom water hydrography of the transect can be evaluated by reference to these assemblages and a comparison to flysch-type agglutinated assemblages from a transect in the North Sea. The presence of an Upper Eocene-Middle Miocene hiatus at the Blue site contrasting with apparently continuous Tertiary deposition at Bonavista places a theoretical upper limit of 500–1000 m on the depth of the early Cenozoic western boundary undercurrent.

African origin of caviomorph rodents is indicated by incisor enamel microstructure

Paleobiology ◽  
1994 ◽  
Vol 20 (1) ◽  
pp. 5-13 ◽  
Author(s):  
Thomas Martin
Keyword(s):  
North American ◽  
Late Eocene ◽  
South American ◽  
Late Oligocene ◽  
African Origin ◽  
Enamel Microstructure ◽  
The North ◽  
Early Oligocene ◽  
Caviomorph Rodents

The same three subtypes of derived multiserial Hunter-Schreger bands are found in the incisor enamel of African phiomorph rodents from the late Eocene-early Oligocene and the oldest South American Caviomorpha from the Deseadan (late Oligocene). The synapomorphies contained therein, especially arrangement and orientation of interprismatic matrix, make an African origin of the Caviomorpha very probable. A North American origin of the Caviomorpha is thus rejected, as only primitive pauciserial Hunter-Schreger bands have been observed in possible ischyromyoid caviomorph ancestors. A multiserial Schmelzmuster apparently never evolved in the North American rodent fauna.

scholarly journals Neogene-Quaternary magmatic activity and its geodynamic implications in the Central Mediterranean region

1997 ◽  
Vol 40 (3) ◽  
Author(s):  
G. Serri
Keyword(s):  
Middle Miocene ◽  
Structural Evolution ◽  
Space Distribution ◽  
Central Mediterranean ◽  
Arc Volcanism ◽  
Time Space ◽  
Lithospheric Extension ◽  
Geodynamic Models ◽  
Back Arc ◽  
Roman Province

The petrogenesis and time/space distribution of the magmatism associated with the formation of the Northern and Southern Tyrrhenian basins, together with the directions and ages of lithospheric extension and/or spreading north and south of the 410N discontinuity, show that the two arc/back-arc systems have undergone a different structural evolution at least since the middle Miocene (Langhian). The geochemical components involved in the genesis of the heterogeneities of the mantle sources of this magmatism require two separate, compositionally different slabs: 1) an old oceanic (Ionian) lithosphere still seismically active below the Calabrian arc and the Southern Tyrrhenian region; 2) an almost seismically inactive continental (Adriatic) lithosphere which carried large amounts of upper crustal materials within the upper mantle under the NW Roman Province/Tuscan/Northern Tyrrhenian region. The proposed geodynamic models require: 1) for the Northern Tyrrhenian/Northern Apenninic arc/back-arc system, the delamination and foundering of the Adriatic continental lithosphere as a consequence of the continental collision between the Corsica block and the Adriatic continental margin. This delamination process, which is still ongoing, probably started in the early-middle Miocene, but earlier than 15-14 Ma, as indicated by the age and petrogenesis of the first documented magmatic episode (the Sisco lamproite) of the Northern Apennine orogenesis; 2) for the Southern Tyrrhenian/Southern Apenninic-Calabrian arc/back-arc system, the roll-back subduction and back-arc extension driven by gravitational sinking of the Ionian oceanic subducted lithosphere. This process started after the end of the arc volcanism of Sardinia (about 13 Ma) but earlier than the first recorded episode of major rifting (about 9 Ma) in the Southern Tyrrhenian back-arc basin.

Sign in / Sign up

Export Citation Format

Share Document