Transactions of the Royal Society of Edinburgh: earth sciences最新文献_第9页

Holocene relative sea levels and coastal changes in the lower Cree valley and estuary, SW Scotland, U.K. 英国苏格兰西南部克里河谷下游及河口全新世相对海平面及海岸变化

Transactions of the Royal Society of Edinburgh: earth sciences Pub Date : 2002-12-01 DOI: 10.1017/S0263593300000456

David E. Smith, J. Wells, T. Mighall, R. A. Cullingford, L. K. Holloway, S. Dawson, Celine Brooks

{"title":"Holocene relative sea levels and coastal changes in the lower Cree valley and estuary, SW Scotland, U.K.","authors":"David E. Smith, J. Wells, T. Mighall, R. A. Cullingford, L. K. Holloway, S. Dawson, Celine Brooks","doi":"10.1017/S0263593300000456","DOIUrl":"https://doi.org/10.1017/S0263593300000456","url":null,"abstract":"ABSTRACT Changes in Holocene (Flandrian) relative sea levels and coastal geomorphology in the lower Cree valley and estuary, SW Scotland, are inferred from detailed morphological and stratigraphical investigations. A graph of relative sea level changes is proposed for the area. Rising relative sea levels during the early Holocene were interrupted at c. 8300–8600 14C years B.P.(c. 9400–9900 calibrated years B.P.), when an extensive estuarine surface was reached at c. −1 m O.D., after which a fluctuating rise culminated at c. 6100–6500 14C B.P. (c. 7000–7500 calibrated years B.P.) in a prominent shoreline and associated estuarine surface measured at 7·7–10·3 m O.D. A subsequent fall in relative sea level was followed by a rise to a shoreline at 7·8–10·1 m O.D., exceeding or reoccupying the earlier shoreline over much of the area after c. 5000 14C B.P. (c. 5,800 calibrated years B.P.), before relative sea level fell to a later shoreline, reached after c. 2900 14C B.P. (c. 3100 calibrated years B.P.) at 5·5–8·0 m O.D., following which relative sea levels fell, ultimately reaching present levels. During these changes, a particular feature of the coastline was the development of a number of barrier systems. The relative sea level changes identified are compared with changes elsewhere in SW Scotland and their wider context is briefly considered.","PeriodicalId":83368,"journal":{"name":"Transactions of the Royal Society of Edinburgh: earth sciences","volume":"27 1","pages":"301 - 331"},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81883394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 22

Magmatism of the Kenya Rift Valley: a review 肯尼亚裂谷的岩浆作用:综述

Transactions of the Royal Society of Edinburgh: earth sciences Pub Date : 2002-09-01 DOI: 10.1017/S0263593300000420

R. Macdonald

{"title":"Magmatism of the Kenya Rift Valley: a review","authors":"R. Macdonald","doi":"10.1017/S0263593300000420","DOIUrl":"https://doi.org/10.1017/S0263593300000420","url":null,"abstract":"ABSTRACT Tertiary–Recent magmatism in the Kenya Rift Valley was initiated c. 35 Ma, in the northern part of Kenya. Initiation of magmatism then migrated southwards, reaching northern Tanzania by 5–8 Ma. This progression was accompanied by a change in the nature of the lithosphere, from rocks of the Panafrican Mozambique mobile belt through reworked craton margin to rigid, Archaean craton. Magma volumes and the geochemistry of mafic volcanic rocks indicate that magmatism has resulted from the interaction with the lithosphere of melts and/or fluids from one or more mantle plumes. Whilst the plume(s) may have been characterised by an ocean island basalt-type component, the chemical signature of this component has everywhere been heavily overprinted by heterogeneous lithospheric mantle. Primary mafic melts have fractionated over a wide range of crustal pressures to generate suites resulting in trachytic (silica-saturated and-undersaturated) and phonolitic residua. Various Neogene trachytic and phonolitic flood sequences may alternatively have resulted from volatile-induced partial melting of underplated mafic rocks. High-level partial melting has generated peralkaline rhyolites in the south–central rift. Kenyan magmatism may, at some future stage, show an increasing plume signature, perhaps associated ultimately with continental break-up.","PeriodicalId":83368,"journal":{"name":"Transactions of the Royal Society of Edinburgh: earth sciences","volume":"9 1","pages":"239 - 253"},"PeriodicalIF":0.0,"publicationDate":"2002-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87737875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 40

Early acanthodians from the Lower Silurian of Asia 来自亚洲下志留世的早期棘足目动物

Transactions of the Royal Society of Edinburgh: earth sciences Pub Date : 2002-09-01 DOI: 10.1017/S0263593300000444

V. Karatajūtė-Talimaa, Moya M. Smith

{"title":"Early acanthodians from the Lower Silurian of Asia","authors":"V. Karatajūtė-Talimaa, Moya M. Smith","doi":"10.1017/S0263593300000444","DOIUrl":"https://doi.org/10.1017/S0263593300000444","url":null,"abstract":"ABSTRACT Abundant microvertebrate remains from the Siberian Platform are described as early acanthodians. All are preserved with both excellent morphology and histology. They are assigned to a new order, Tchunacanthida, with two new families, Lenacanthidae and Tchunacanthidae. These comprise two new genera, Lenacanthus and Tchunacanthus with type species L. priscus sp. nov. and T. obruchevisp.nov. The evidence from the morphology and histology is that they are the most ancient acanthodian scales so far found. The total collection of vertebrate material from the Irkutsk amphitheatre is described, together with their geological distribution, geographical range and systematic palaeontology. Head scales, tesserae of three morphotypes, transitional scales and body scales have been found. All comprise morphological sets as determined by comparison of morphology using SEM and of histology using Nomarsky interference optics. Observations of growth were possible from details of concentric lines on the crown and also from incremental layers seen in both horizontal and vertical sections. Starting from the primordial scale, consecutive layers are added, coronally, laterally, and deep in the corium onto the base; these occurred simultaneously in both crown and base. A type of areal-superpositional growth occurred in some body scales but in other scales there was little superpositional growth. It is concluded that Tchunacanthus possessed very solid body armour with tightly joined scales covering a large area of the body, and scale bases deeply set in the corium. Both tissues of the scales, dentine and bone, feature enclosed cells. This character is regarded as primitive within acanthodians, as in derived forms both tissues are acellular. Acanthodian scales are one of many examples of transformation from cellular to acellular tissue in evolution.","PeriodicalId":83368,"journal":{"name":"Transactions of the Royal Society of Edinburgh: earth sciences","volume":"3 1","pages":"277 - 299"},"PeriodicalIF":0.0,"publicationDate":"2002-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83257169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 25

Revision of the Xenacanthida (Chondrichthyes: Elasmobranchii) from the Carboniferous of the British Isles 不列颠群岛石炭纪xenacanthia (chondrichth亚目:Elasmobranchii)的修正

Transactions of the Royal Society of Edinburgh: earth sciences Pub Date : 2002-09-01 DOI: 10.1017/S0263593300000419

O. Hampe

{"title":"Revision of the Xenacanthida (Chondrichthyes: Elasmobranchii) from the Carboniferous of the British Isles","authors":"O. Hampe","doi":"10.1017/S0263593300000419","DOIUrl":"https://doi.org/10.1017/S0263593300000419","url":null,"abstract":"ABSTRACT Xenacanthids were a very successful group of elasmobranchs that ranged from the Lower Carboniferous to the Upper Triassic. The history of discovery of the xenacanthids, which is closely connected with the history of coal prospecting in England, began with the finding of the type specimen of Xenacanthus laevissimus in the Westphalian B of the West Midlands. In this first review of British Carboniferous xenacanthids, the number of taxa, mainly erected during Victorian times, is reduced to 14 species distributed among six genera. Determinable remains are recorded from at least 96 localities in the British Isles. Unique characteristics of the Dinantian Diplodoselache suggest that the lineage to which this taxon belongs marks a dead end in xenacanthid evolution. This investigation also shows that the Pendleian Dicentrodus, formerly described as Cladodus, belongs to the xenacanthids. The occurrence of Orthacanthus cf. kounoviensis in the Pennines, also known from the German Saar-Nahe basin, the Saale depression and from Bohemia, indicates a faunal exchange between these intramontainous basins during the Carboniferous. The genus Triodus is identified from British deposits for the first time. A cladistic analysis of the xenacanthids suggests that they evolved from phoebodontid elasmobranchs. This analysis also confirms separation of the Middle Devonian Antarctilamna from a relationship with xenacanthid sharks.","PeriodicalId":83368,"journal":{"name":"Transactions of the Royal Society of Edinburgh: earth sciences","volume":"114 1","pages":"191 - 237"},"PeriodicalIF":0.0,"publicationDate":"2002-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77571079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 41

Mandibles of rhizodontids: anatomy, function and evolution within the tetrapod stem-group 根状齿的下颌骨:四足动物茎群的解剖、功能和进化

Transactions of the Royal Society of Edinburgh: earth sciences Pub Date : 2002-09-01 DOI: 10.1017/S0263593300000432

J. Jeffery

{"title":"Mandibles of rhizodontids: anatomy, function and evolution within the tetrapod stem-group","authors":"J. Jeffery","doi":"10.1017/S0263593300000432","DOIUrl":"https://doi.org/10.1017/S0263593300000432","url":null,"abstract":"ABSTRACT The Rhizodontida (Pisces: Sarcopterygii) is a clade of predatory fishes from the Upper Devonian (Aztecia; ?Givetian of Antarctica) through to the Upper Carboniferous (Strepsodus; Moscovian of northern Europe and North America). They form the most basal plesion within the tetrapod stem-lineage. The mandibles were dominated by large symphysial tusks on the dentary. Not much else is known of the mandibles in primitive rhizodontids. However, later forms show several derived characters: the mandible is very deep dorsoventrally and narrow linguolabially; the coronoid fangs bear only a single fang and no other dentition; the Meckelian element was unossified, leaving the adductor fossa unfloored by bone; the prearticular produced a large dorsal process lingual to the adductor fossa, presumably for muscle attachment. These and other characters are discussed in the context of the evolution of the tetrapod stem-group. The mandible appears to have been split into two functional units, one comprising the firmly sutured prearticular, coronoids and dentary, the other comprising the firmly sutured infradentaries. The connection between the two units was weak, suggesting a longitudinal intramandibular hinge. The possibility that this acted as a ‘torsion grip’ during feeding is discussed.","PeriodicalId":83368,"journal":{"name":"Transactions of the Royal Society of Edinburgh: earth sciences","volume":"1995 1","pages":"255 - 276"},"PeriodicalIF":0.0,"publicationDate":"2002-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82449960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 25

New camerate crinoids from the Ordovician of Scotland and Wales 苏格兰和威尔士奥陶纪的新照相机海百合

Transactions of the Royal Society of Edinburgh: earth sciences Pub Date : 2002-06-01 DOI: 10.1017/S0263593300000389

S. Donovan, Neil Gilmour

引用次数: 6

The Silurian Mulde Event and a scenario for secundo–secundo events 志留纪Mulde事件和秒-秒事件的场景

Transactions of the Royal Society of Edinburgh: earth sciences Pub Date : 2002-06-01 DOI: 10.1017/S0263593300000377

L. Jeppsson, M. Calner

{"title":"The Silurian Mulde Event and a scenario for secundo–secundo events","authors":"L. Jeppsson, M. Calner","doi":"10.1017/S0263593300000377","DOIUrl":"https://doi.org/10.1017/S0263593300000377","url":null,"abstract":"ABSTRACT Graphic correlation using graptolites and conodonts provides a high-resolution timescale for correlating from coastal to deep oceanic sections and, thereby, also a detailed record of the sequence of changes during the Mulde Secundo-Secundo Event. That interval includes sedimentary facies otherwise unknown in older Wenlock to early Ludlow strata on Gotland. The identified sequence of changes includes a detailed record of, in order: two extinctions (Datum points 1 and 1·5); widespread deposition of carbon-rich sediments extensive enough to cause a δ13C increase of c. 4.8‰, the onset, maximum and end of a sea-level fall and rise of at least 16 m during 30 kyr; a third extinction (Datum 2); a disaster fauna; and a slow faunal recovery. Thus, a secondary result of the event was a weakened greenhouse effect triggering a glaciation: the Gannarve Glaciation (new term). The order of changes proves that regression did not cause the extinctions. Faunal and sea-level changes, as well as the sedimentary succession, fit well with predictions based on an oceanic model. Extinctions were primarily caused by a severe drop in primary planktonic productivity, causing starvation among planktonic larvae in non-coastal settings. The Grötlingbo Bentonite (new term), the thickest in the Wenlock of Gotland, was deposited across the basin shortly after Datum 2. Temporal resolution is high enough to permit some comparison with Quaternary glaciations.","PeriodicalId":83368,"journal":{"name":"Transactions of the Royal Society of Edinburgh: earth sciences","volume":"12 1","pages":"135 - 154"},"PeriodicalIF":0.0,"publicationDate":"2002-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81415866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 101

The trilobite Family Illaenidae Hawle et Corda, 1847 from the Ordovician of the Prague Basin (Czech Republic) 三叶虫Illaenidae Hawle et Corda, 1847年来自布拉格盆地奥陶纪(捷克共和国)

Transactions of the Royal Society of Edinburgh: earth sciences Pub Date : 2002-06-01 DOI: 10.1017/S0263593300000407

J. Bruthansová

引用次数: 14

A chitinozoan biostratigraphy of the Upper Ordovician and lower Silurian strata of the Girvan area, Midland Valley, Scotland 苏格兰米德兰谷地Girvan地区上奥陶统和下志留统地层的几丁虫生物地层学

Transactions of the Royal Society of Edinburgh: earth sciences Pub Date : 2002-06-01 DOI: 10.1017/S0263593300000365

T. Vandenbroucke, J. Verniers, E. Clarkson

{"title":"A chitinozoan biostratigraphy of the Upper Ordovician and lower Silurian strata of the Girvan area, Midland Valley, Scotland","authors":"T. Vandenbroucke, J. Verniers, E. Clarkson","doi":"10.1017/S0263593300000365","DOIUrl":"https://doi.org/10.1017/S0263593300000365","url":null,"abstract":"ABSTRACT Forty-six samples, taken from the Upper Ordovician and lower Silurian strata of the Girvan district, Midland Valley of Scotland, yield moderately well-preserved and diverse assemblages of chitinozoans. The area was chosen to study the composition of the chitinozoan assemblages, rarely described before in Scotland, which lay at the south-eastern margin of the Laurentia palaeocontinent. These assemblages are compared with those of the same age on other palaeocontinents, representing a critical time when both the Iapetus and Tornquist oceans were closing, thus forming the Caledonide and associated orogens. It is possible to correlate the chitinozoan occurrences at Girvan with those of other parts of Laurentia (Quebec area), other palaeocontinents such as Baltoscandia (Sweden, Estonia), Avalonia (Wales, Brabant Massif) and some parts of Northern Gondwana (Saudi Arabia). For the lower Silurian, it is possible to correlate with the global chitinozoan biozonation, and a calibration between the chitinozoan occurrences and the graptolite biozonation of Girvan is established. Several levels within the Balclatchie, South Shore, Three Mile, Shalloch, Wood Burn, Lauchlan, Drumyork Flags and other formations are accurately dated.","PeriodicalId":83368,"journal":{"name":"Transactions of the Royal Society of Edinburgh: earth sciences","volume":"42 1","pages":"111 - 134"},"PeriodicalIF":0.0,"publicationDate":"2002-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77798819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 25

A revised reconstruction of the dermal skull roof of Acanthostega gunnari, an early tetrapod from the Late Devonian 泥盆纪晚期早期四足动物冈纳棘螈真皮头盖骨顶的修正重建

Transactions of the Royal Society of Edinburgh: earth sciences Pub Date : 2002-06-01 DOI: 10.1017/S0263593300000390

J. Clack

引用次数: 29