摘要:

Dissection of fine‐grained turbidites within the Franciscan complex at Trinidad Harbor reveals intrastratal zonation of biogenic structures. The pre‐depositional association comprises only three ichnotaxa (preserved in convex hyporelief) and is less diverse than the tiered post‐depositional association (comprised by at least seven ichnotaxa preserved in full relief). The latter association is dominated byMelatercichnus(n. ichnogen.). Post‐depositional trace‐makers exploited abundant plant detritus deposited with the turbidite sand. Temporal alternation of trace fossil associations resulted from the infrequent, but catastrophic, disturbance of pre‐turbidite communities and local replacement by assemblies of opportunistic organisms. Although probably short‐lived at specific sites, the post‐turbidite infauna was tiered, enabling a variety of deposit feeders to harvest phytodetritus of varied size or density simultaneously at different depths within newly deposited turbidite sand layers.

ISSN:1042-0940    

DOI:10.1080/10420949109386349

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Early to Late Silurian (Llandovery‐Ludlow) body and trace fossils from the Heceta Formation of southeastern Alaska are preserved in the oldest widespread carbonates in the Alexander terrane. These fossils represent the earliest benthos to inhabit diverse shallow and deep subtidal environments in the region and are important indicators of early stages in benthic community development within the evolving Alexander arc. The ichnofossils are particularly significant because they add to a small but growing body of knowledge about trace fossils in deep‐water carbonates of Paleozoic age.

ISSN:1042-0940    

DOI:10.1080/10420949109386350

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Large, well‐preservedZoophycosspecimens are abundant and widespread in the Amuri Limestone Group (Upper Cretaceous‐lower Oligocene) on the South Island of New Zealand. Although several previous workers have offered detailed descriptions ofZoophycosin the group, their hypotheses concerning its mode of production have flaws. We propose a new ethologic explanation ofZoophycosthat avoids pitfalls of previously published explanations.

ISSN:1042-0940    

DOI:10.1080/10420949109386351

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Additional discoveries of well‐preserved trace fossils in the Miocene Waitemata Group of Northland, New Zealand, have permitted recognition of two new ichnotaxa.Rorschachichnus amoebais a small, crudely globose trace fossil of irregularly reticulate outline. It is interpreted as a mining trace, possibly by a small meiofaunal arthropod progenitor, and is typically associated with theNereitesichno‐facies that is characteristic of flysch sequences.Piscichnus waitematais a large, plug‐shaped trace fossil, considered to be an analog of modern eagle ray (elasmobranch) foraging pits, and is conspicuous in shallow‐marine deposits.

ISSN:1042-0940    

DOI:10.1080/10420949109386352

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Traces interpreted asSkolithossp. in aGlossifungitesichnofacies occur in the upper part of the Beans Gap Claystone paleosol, in association with a Late Ordovician marine erosional surface. Paleosol color and whole‐rock chemistry are distinctly different in the vicinity of burrows, which are enveloped by olive gray mottles, 1 to 10 cm in diameter, in which total iron (measured as Fe2O3) is 30% lower than in grayish red, “unaltered”; claystone.

ISSN:1042-0940    

DOI:10.1080/10420949109386353

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A trace fossil assemblage from the Lower Jurassic East Berlin Formation of the Newark Supergroup, Hartford Basin, New England, USA, includes:Scoyenia gracilis, Skolithosichnosp.,Palaeophycus striatus, Planolites montanus, Fuersichnusichnosp., fusiform burrows, pelleted material, an escape structure, and large burrows.

ISSN:1042-0940    

DOI:10.1080/10420949109386354

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Scratchings, forming two partial scratch circles, surround a narrow, filled tube probably formed by a plant stem. The scratchings are interpreted to have formed as follows: Water currents carrying sediment onto a floodplain swirled around the plant leaves, etching out partial scratch circles on the sediment surface. Later settling of the finest material resulted in a veneer of mud filling the scratch circles. Drag marks on the bedding surface were formed by the same processes. Later drying of the mud resulted in the formation of desiccation cracks.

ISSN:1042-0940    

DOI:10.1080/10420949109386355

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The animal (as opposed to the fucoidal) origin ofRusophycusand numerous other traces was well understood by Dawson nearly a decade before the appearance of the first writings by Nathorst on this subject. Dawson also understood the toponomic processes by which trilobite traces were preserved as sole casts or hypichnia.

ISSN:1042-0940    

DOI:10.1080/10420949109386356

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A Bibliography of the Dinosauria (Exclusive of the Aves) 1677–1986, by Daniel J. Chure and John S. McIntosh, 1989. Museum of Western Colorado, 248 South 4th Street, Grand Junction, Colorado 81502, USA. 226 pages. US$25.00.

ISSN:1042-0940    

DOI:10.1080/10420949109386357

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:1042-0940    

DOI:10.1080/10420949109386348

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor