New record of the trimerellid brachiopod Gasconsia, a rare Silurian lazarus taxon

2002 ◽  
Vol 76 (1) ◽  
pp. 185-186 ◽  
Author(s):  
Rodney Watkins
Keyword(s):  
New Record ◽  
Upper Ordovician ◽  
The North ◽  
North Side ◽  
Upper Silurian

Gasconsia Northrop, 1939, is a rare trimerellid that appears in the Upper Ordovician (Ashgill) and then reappears in the Upper Silurian (Wenlock/Ludlow) (Hanken and Harper, 1985; Popov and Holmer, 2000). This note is the first documented report of Gasconsia from the type Ludlow of the Welsh Borderland. Gasconsia transversus (Salter) occurs in the Lower Bringewood beds (upper part of Gorstian stage) in a small quarry on the north side of the Holloway to Upper Millichope road, directly opposite the entrance to Millichope Park (grid ref. SO 52748911). The material consists of internal and external molds of one brachial valve and one articulated individual (Fig. 1). This species was described as Obolus Davidsoni var. transversus [Salter MS] by Davidson (1866) from the Wenlock (Homerian stage) of the Dudley and Woolhope areas of the English Midlands and Welsh Borderland. Davidson and King (1874) subsequently referred to it as Dinobolus transversus (Salter), and Cocks (1978), in selecting a lectotype of transversus, retained its assignment to Dinobolus. However, illustrations of transversus in Davidson (1866, pl. 5, figs. 1-6) and Davidson and King (1874, pl. 18, fig. 12) clearly show that it belongs in Gasconsia rather than Dinobolus.

scholarly journals Upper Ordovician – Upper Silurian conodont biostratigraphy, Devon Island and southern Ellesmere Island, Canadian Arctic Islands, with implications for regional stratigraphy, eustasy, and thermal maturation

2016 ◽  
Vol 53 (9) ◽  
pp. 931-949 ◽  
Author(s):  
Shunxin Zhang ◽  
Khusro Mirza ◽  
Christopher R. Barnes
Keyword(s):  
Canadian Arctic ◽  
Hydrocarbon Exploration ◽  
Upper Ordovician ◽  
Conodont Biostratigraphy ◽  
Thermal Maturation ◽  
Devon Island ◽  
The North ◽  
Cape Phillips Formation ◽  
Upper Silurian ◽  
Local Range

The conodont biostratigraphy for the Upper Ordovician – Upper Silurian carbonate shelf (Irene Bay and Allen Bay formations) and interfingering basinal (Cape Phillips Formation) facies is established for parts of Devon and Ellesmere islands, central Canadian Arctic Islands. Revisions to the interpreted regional stratigraphic relationships and correlations are based on the stratigraphic distribution of the 51 conodont species representing 32 genera, identified from over 5000 well-preserved conodonts recovered from 101 productive samples in nine stratigraphic sections. The six zones recognized are, in ascending order, Amorphognathus ordovicicus Local-Range Zone, Aspelundia fluegeli Interval Zone, Pterospathodus celloni Local-Range Zone, Pt. pennatus procerus Local-Range Zone, Kockelella patula Local-Range Zone, and K. variabilis variabilis – Ozarkodina confluens Concurrent-Range Zone. These provided a more precise dating of the members and formations and, in particular, the range of hiatuses within this stratigraphic succession. The pattern of regional stratigraphy, facies changes, and hiatuses is interpreted as primarily related to the effects of glacioeustasy associated with the terminal Ordovician glaciation and smaller Early Silurian glacial phases, the backstepping of the Silurian shelf margin, and the geodynamic effects of the collision with Laurentia by Baltica to the east and Pearya to the north. Conodont colour alteration index values (CAI 1–6.5) from the nine sections complement earlier graptolite reflectance data in providing regional thermal maturation data of value in hydrocarbon exploration assessments.

A Radiocarbon-dated Collared Urn from Oban

2001 ◽  
Vol 23 (2) ◽  
pp. 105-118
Author(s):  
CHRISTOPHER LOWE ◽  
ANN MacSWEEN ◽  
KATHLEEN McSWEENEY
Keyword(s):  
The North ◽  
North Side ◽  
Funerary Ritual

A collared urn was found during the course of a watching-brief on the raised beach on the north side of Oban bay. Post-excavation analysis has succeeded in throwing some further light on the chronology of this type of urn and possibly on some elements of the funerary ritual associated with its burial. The same watching-brief also revealed the site of a truncated pit of medieval date, filled with fire-cracked stones.

Influence of Pumps on Salinity of a Coastal Aquifer with Legal Protection (A Zone in the North of Isla Cristina, Huelva, Spain)

1991 ◽  
Vol 24 (11) ◽  
pp. 251-260 ◽  
Author(s):  
A. González ◽  
E. Romero
Keyword(s):  
Coastal Aquifer ◽  
Salt Water ◽  
Legal Protection ◽  
Hydraulic Gradient ◽  
Water Mixture ◽  
Residual Flow ◽  
Legal Requirements ◽  
The North ◽  
North Side ◽  
Rational Distribution

In this article we show that the legal measures for protection of aquifers are not enough to lessen the pumping if the users are not associated and determined to have a rational distribution of water. The expansive agriculture on the North side of Isla Cristina (Huelva, Spain), based on citrus and strawberry growing, uses high volumes of groundwater that comes from a tertiary age detritic coastal aquifer with a significant lack of resources. This causes a decrease of the residual flow to the sea, deep pumpcones, and an inversion of the hydraulic gradient, which initiates the progressive salinization of the aquifer northwards, in the sense that the fresh-salt water mixture zone is moving. The problem is worsening because the number of uncontrolled pump-works in the areais increasing. This problem could be alleviated if a Users Community for the whole aquifer were created, itself to watch over the fulfilment of the legal requirements and to regulate the water extractions.

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