New Boreholes Into Permian Beds Off Northumberland and Durham

Magraw, D.

doi:10.1144/pygs.42.2.157

Cited by 4 publications

(2 citation statements)

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“…The core is from VT8 borehole (Grid Ref. NZ 4862 5095) and details of the full sequence are given by Magraw (1978). The part of the core analysed is 144 cm thick and stable isotope and chemical analyses have been made at 1 cm intervals throughout.…”

Section: P Turner and M Magaritzmentioning

confidence: 99%

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Chemical and isotopic studies of a core of Marl Slate from NE England: influence of freshwater influx into the Zechstein Sea

Turner

Magaritz

1986

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SUM M A RY: Detailed mineralogical, chemical and stable isotope analyses have been made of single core through the Marl Slate in order to investigate the Zechstein transgression and its associated mineralization. The core (VT8), drilled by the National Coal Board offthe coast of NE England, contains three subfacies: (1) dark grey, organic-rich, sapropelic siltstones; (2) organic-dolomite laminites; (3) massive finely crystalline dolostones. Two cycles of deposition which include the sequence sapropel~laminite~dolostone are present although the lower one (112 cm) is much thicker than the upper (32 cm).There are some close correlations between the lithological and geochemical variables, including the stable isotope values. The sapropelic units are characterized by high Fe content (as iron sulphide) and strongly negative 6180 values in associated carbonate minerals. Quartz silt and organic carbon are also higher in these units but diminish upwards in each depositional cycle. Each cycle of deposition appears to have been initiated by an influx of freshwater into the Zechstein basin which promoted surface productivity, water stratification and regional anoxic conditions. The relative change in 6'3C to more positive values higher in the Marl Slate is independent oflithological variation and indicates progressive enrichment of ~3C in the Zechstein Sea in response to the precipitation of large amounts of organic matter.The distribution of base metals in the Marl Slate in this core strongly suggests that they were introduced by freshwater influx. Although Pb shows no clear relationship to the depositional cycles, Cu and Zn contents are relatively low in the lower sapropelic parts of the cycles and become higher in the upper parts. We take this to indicate that Cu and Zn sulphides were precipitated interstitially when more 'normal' marine conditions were re-established in the later part of each cycle.

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Section: P Turner and M Magaritzmentioning

confidence: 99%

“…It is not possible to place a precise boundary between the two units although the Marl Slate (s.s.) as reported in this paper is probably no more than 1 m thick. The part of the core analysed is 144 cm thick and is a complete sequence of the Marl Slate and part of the overlying Passage Beds of Magraw (1978).…”

Section: Lithological Variation Of the Vt8 Corementioning

confidence: 99%