• Nie Znaleziono Wyników

A contribution to the petrology of the Middle Jurassic of Whitby, Yorkshire

N/A
N/A
Protected

Academic year: 2021

Share "A contribution to the petrology of the Middle Jurassic of Whitby, Yorkshire"

Copied!
11
0
0

Pełen tekst

(1)

a contribution to tiie petroiogy

of the middie j u r a s s i c

of w l i i t b y , yoricsliire

s o m e r e s u i t s on dogger s a m p i e s

by K - H . A . A . W o i f

R . A . K u l i n e i

G . K w a n t e s

C.l\fiaugenest

(2)

K E U T E R

Elektronische Steuer- und

Regelanlagen - Microcomputer

Wir entwickeln, betreiben Zulassungen bei BVS, PfG,

Loba und fertigen elektronische Gerate, sowie Aniagen

für den Bergbau und andere Industrien.

4200 Oberhausen 11 (Sterkrade)

WeiBensteinstraBe 109 - Ruf 02 08 / 66 63 04

BERGBAU

AUSRÜSTUNGEN

Karl Hamacher GmbH

Maschinenfabrik

Rohrleitungs- und Armaturenwerk

Watermannsweg 27/31 - 4630 Bochum 6 Postfach 600387 - Telefon 02327/88061/63 Fernschreiber O 820 445

^0A.

A CONTRIBUTION TO THE PETROLOGY OF THE MIDDLE JURASSIC OF WHITBY, YORKSHIRE: SOME RESULTS ON DOGGER SAMPLES

by

K-H. A. A. Wolf, R. A. Kühnel, G. Kwantes, C. Maugenest

INTRODUCTION

In juiy 1986, first and second year Mining and Petroleum Engineering students visited the east-cliff of Whitby during a field-trip to Northern England and Scotland. This cliff-section illustrated beautifully examples of a Middle Jurassic deltaic environment. Clearly recognizable are channels, crevasse splays and lagoonal or swamp deposits. The section can be compared with the Middle Jurassic deltaic environment of the Brent Group. The wavecut platform shows bituminous shales of the Upper Lias. Be-tween these rather interesting eye-catchers, a modest unconformity with overlying Dogger is presented. This thin brownish-red layer can be reached at one place, on which Gerard Kwantes took some samples. Thin sections of these samples showed an interesting mineralogy, that only for a part was described in literature. In September 1986 a second journey was made to Whitby, to the examine Dogger and adjacent lay-ers, in greater detail. During this five-day fieldwork, several subjects have been treated:

1) The geology of the east cliff of Whitby and the Dogger formation as a main point. 2) Sampling of the Dogger formation and adjacent layers for geochemical and

minera-logical research.

3) An Engineering Geological study on the precise determination of the locations of the Dogger outcrops, together with a study on the stability of the cliffs.

GEOLOGICAL BACKGROUND (Figure 1, 2)

The Lower Jurassic in Yorkshire consists mainly of fossiliferous marine shales and various types of siltstones, sandstones and ironstones. Cyclic sequences from shales to sands often occur. They are most clearly observed in the Upper Lias. The Upper Lias succession is regarded as being laid down in waters of decreasing depth and in-creasing oxygenation of the bottom sediments. The finely laminated shales contain a high percentage of pyrite and calcium carbonate concretions (for example the jet rock). The original parent mud contained much H j S and CaCOa, the products of bacterial break down of sulphates in sea water. Fossile remnants of bivalves, ammonites, be-lemnites, fish, reptiles and waterlogged wood can be found in these shales (Hemming-way 1974).

At the end of Toarcian times north-east Yorkshire was folded into a series of shallow basins and low domes. The seafloor was raised to sea-level and marine erosion rewor-ked Upper Lias strata of various thicknesses. During and after this low amplitude fol-ding and uplifting, at the beginning of Bajocian times, the erosion products were depo-sited mainly in a shallow marine environment (Hanckock and Fisher 1981). This basal formation, named the Dogger, is a rather heterogenous sediment in thickness as well as in sediment content in the Yorkshire area. The sedimentation of the Dogger spans a relatively long period of time, one might speak of a condensed sequence. This thin formation at the beginning of the Middle Jurassic should not be confused with the European usage of the term Dogger which is the term used to denote the whole of the Middle Jurassic (Figure 2).

(3)

Figure 1 A: A section of the cliffs on the east side of Whitby with the sample spots (0, I, II, III etc.)

Figure 1 B: A scetch map of the geology at the east-cliff and on the wave cut plat-form between Whitby and Saltwick Nab.

126

Figure 2. Nomenclature of Upper Lias and Middle Jurassic strata. After Powel (1984) and Hemingway & Knox (1973)

SCALBY FORMATION S C A R B O R O U G H FORMATION MIDDLE C L O U G H T O N FORMATION JURASSIC ELLERBECK FORMATION

SALTWICK FORMATION DOGGER FORMATION

B L E A W Y K E SANDSTONE Y E L L O W SANDSTONE FORMATION GREY S A N D S T O N E LOWER UPPER FOX CLIP SILTSTONE JURASSIC LIAS WHITBY PEAK M U D S T O N E

M U D S T O N E A L U M SHALE FORMATION JET ROCK

GREY SHALE

Photo 1: A vertical profile of the Dogger at Long Bight, Whitby East Cliff.

(4)

After the marine Dogger filled most of the depressions in the Liassic surface, a marshy deltaic facies dominated the Yorkshire basin. The clastic terrigenous sediments were deposited during the Middle-Jurassic and are thought to have a northern provenance (Hemmingway/Knox 1973).

LOCAL STRATIGRAPHY

The stratigraphy as can be seen on the east-cliff of Whitby consists of five recognizable members and formations (Figure 1 a, b, Photo 1, 2, 3.):

1) The Jet Rock Member.

This rock type is a member of the Whitby Mudstone Formation (Powel 1984) which is a part of the Upper Lias. The Jet Rock member is a group of dense finely laminated, dark brown shales with several beds of calcareous concretions. These shales are cog-nate to oil shales. They produced on laboratory distillation 54-86 litres of sulphurous oil to a ton (Hemingway 1973). Besides illite, chlorite and kaolinite as the clay minerals and dispersed sand and silt as quartz content, pyrite is abundant up to 1 5 % . The CaCOj-content is relatively high, from an average of circa 6 % to circa 1 9 % at the top. Fossil ammonites, belemnites, wood (jet) and remains of reptiles can be found. The Jet Rock is capped by a thin and platey argillaceous limestone, the Top Jet Dogger (not to confuse with the Dogger Formation).

2) The Alum Shale Member.

The lower part of the member consists of a hard shale with nodular and tabular siderite mudstones. The overlying Main Alum Shales are grey in colour and weak. They weath-er vweath-ery fast in comparison with the shales of the Jet Rock Membweath-er. The principal detri-tal minerals are quartz, muscovite, chlorite and biotite, with small amounts of feldspar, tourmaline, rutile etc. Belemnites, ammonites and small bivalves are common. The Alum Shale series was used for the production of alum for almost 300 years (Photo 1).

Both members represent the top of the Upper Lias in this part of the Yorkshire area. They show a gently folded open structure, uncomformably overlain by the Dogger For-mation. The upper part of the Whitby Mudstone Formation and the Blea Wyke Sandstone Formation have been eroded during this phase of uplift and slight deforma-tion (Photo 1).

3) The Dogger Formation.

The Dogger at the east cliff is a brown to reddish, pebbly, ferruginous sideritic siltstone about 60 to 80 cm thick with a very irregularly weathered top. The base is marked by a conglomerate. The silt matrix shows random deposited coarser grains of quartz, feldspar, phosphates and siderite (Photo 1, 2, 3).

4) The Saltwick Formation

The Saltwick Formation is a non-marine formation. It comprises marsh deposits and channel deposits. The marsh deposits consist of plane-bedded clays, silts, ill-graded sandstones and silty ironstones. These show local cyclicity and a fining upward from an argillaceous sandstone, trough silt to a leached clay and ends in a carbonaceous clay or a low grade coal. Local folding and faulting are frequent at the channel mar-gins, because of the difference in compaction between the clay-rich sediment (a rather high compaction-rate) and the sand-rich sediments.

128

The Channel deposits are the washouts, deposits which fill the erosive channels and dissect, both marine (Liassic members and Dogger) and non-marine subjacent sedi-ment. These channels are commonly filled with sandstones and they lie sharply in con-tact with the sediments into which the channel has cut. Fossil plants and bivalves have been recognized in both marsh deposits and channel deposits. In some sandstone blocks which fell on the wave-cut platform due of erosion of the cliffs, three toed foot-prints of several reptiles are visible.

5) The Ellerbeck Formation.

The formation comprises marine ironstones, shales and sandstones. They contain bi-valves, gastropods, ichnofauna and wood debris. Ammonites are rare.

THE INVESTIGATION

At the east-cliff of Whitby the Dogger formation and adjacent formations were laterally and vertically sampled at eight outcrops. Furthermore samples were gathered at the north side of the Peak Fault at Ravenscar. At each sample point the thickness and con-tent of the layers were recorded.

Basic petrography and modal analyses by optical microscopy (table 1, photo 4, 5, 6) were supplemented by X-ray diffraction (X.R.D.) to confirm and to quantify silica and carbonate mineralogy (table 2).

Simultanous Differential Thermal Analyses (D.T.A.) and Thermo-gravimetry (T.G.) were carried out by means of the Derivatograph. On recordings of thermal analyses it was possible to recognize the thermal behaviour of particular constituents (figure 3, 4). Powdered samples (325 mesh) were analyzed at atmospheric conditions within the range of 2 0 ° C to 1000°C and at a heating rate of 10°C/min.

Scanning Electron Microscopy (S.E.M.) was used to throw light upon the three-dimen-sional relationship between detrital and authigenic phases (Photo 7-13).

In the first stage of the investigation the samples of the Dogger Formation were being used for an analyses, discern the nature of the sedimentology of the condensed se-quence at the east-cliff of Whitby. In a second stage the adjacent layers were examined.

PRELIMINARY RESULTS

Petrography (photo 4, 5, 6, table i ) .

Some eighty samples were collected from eight outcrops on the east-cliff at Whitby and from one outcrop near Ravenscar. The majority of the samples described here we-re collected from the Dogger formation.

At Long Bight the Dogger Formation (Thickness circa 80 cm), a ferruginous sand with phosphatized pebbles was sampled each 15 meter. The Dogger shows four recogniza-ble zones (photo 1, 2, 3):

Top Layer D; Circa 5 cm thickness. Reddish, ferruginous, carbonate rich sandstone. The inhomogenous sediment composition caused a very irregular weathering of the top (photo 1, 2). Under this zone the colour of the rock changes from red to dark grey.

Top Layer C: Circa 10 cm thichness. Reddish-brown, ferruginous, carbonate rich sandstone, very irregularly weathered. Under the weathered skin, the colour of the rock changes from red to dark grey (photo 1, 2). Both layers are only recognizable at the central part of Long Bight. They seem to dis-appear to the east and west. Top layer A has a higher sand content in comparison with Top layer B.

(5)

Main Layer B: Circa 60 cm thickness. Brownish-grey carbonatic sandstone with a change in mineral composition and in grain size from the top to the bottom. At the top often white spots of kaolinite are recognizable. They disappear downwards. A coarsening upward of the sand fraction, an increase in grainsize of the pebbles and an increase of the carbonate content upward, can be seen in all Dogger outcrops. Xenomorphic rel-icts of fossil vegetation and charcoal-like remnants are random in the groundmass. Often kaolinite can be recognized around the particle and in cracks in the particle.

Bottom A: Circa 5 cm thickness. Zone with coarse, irregularly poor sorted peb-bles in a matrix of sand. The pebpeb-bles consist mostly of Fe/Ca-Carbonate and phospatic matter (photo 3).

Microscopic results (photo 4, 5, 6, table 1)

The thin sections analyzed by polarization microscopy, show a constant vertical mine-ralogical content. At each sample point the proportions in mineral content change from the bottom to the top of the formation. The main components are quartz, feldspar and phosphate minerals in a sideritic matrix. Of less frequent occurence are the clay-minerals (illite, kaolinite and chlorite), muscovite/biotite, organic matter, pyrite and ac-cessoric minerals as zircon etc,

•) The quartz grains can be divided in two groups:

1) sub-rounded to well-rounded grains with a diameter of 1 mm or bigger. 2) sub-angular to sub-rounded grains with a high to low sphericity, which are often

the main part of the grains.

•) The feldspar grains can be divided into the same groups as the quartz-grains. How-ever the fraction of small grains is difficult to recognize. The larger grains often show twinning and some even have microciine gitterung which might point to a py-roclastic origin of the feldspar grains. Many of the plagioclase have been partly re-placed by calcite and/or kaolinite.

•) The carbonate minerals are present in three different forms in the thin sections: 1) Sideritic spherulites as the main constituent of the groundmass. At the top of the formation, in the siderite rich zone, the spherulites are twice as large (0.04 mm) than at the bottom (0.01 mm). The cores of the spherulites often contain more iron than the rim.

2) Sideritic carbonate at the bottom of the formation is a blocky type cementation between the quartz and feldspar grains. It has often been replaced by siderite spherulites.

3) Calcite has replaced feldspar grains during diagenesis.

4) Some quarz, feldspar and phosphate grains have a coating of sideritic car-bonate.

Of special note is the absence of carbonate bioklasts like remnants of bivalves and crinoids in this carbonate-rich environment.

• ) The phosphatic minerals are grains with a high sphericity and roundness. They of-ten contain very fine clay-minerals, such as chlorite and illite, together with a very fine silt fraction. They also show a concentric zoning. Collophane, a cryptocristalli-ne apatite forms the groundmass of these phosphatic grains.

•) Most of the clay-minerals are authigenic particles, grown in collophane and feldspar grains. Kaolinite also can be seen as a weathering product in cracks in charcoal remnants.

•) Organic matter mostly consists of charcoal remnants with kaolinite. The kaolinite can be seen in cracks in the particle and around the particle.

(6)

Table 1; The interpretation of the mineral-history of the Dogger Formation by optical microcopy.

Mineral Caledonian origin Liassic stage Dogger stage Diagenesis Clastic sediments Clastic Clastic/Chemic Authigenesis Quarz + + + + + Sedimentation Reworking

Feldspar •¥ + + + + Sedim/Volcanic Reworking Break down Siderite +++++++ Replacement Cacite Bio/lithoclasts Recryst. P l a g - » C c Apatite/ P l a g - » C c Collophane '?+ + + + + - H -1- + -1- + ? + + + -1-Musc/Biotite -h + -1- + + M i c a - » Illite Illite "?+ + + + + + + + + + Chlorite + + + + + Kaolinite P l a g ^ Kaol. Pyrite + + + + + + + + + +

D.T.A and T.G. results (figure 3, 4)

Simultaneous differential thermal analyses (D.T.A.) and thermogravimetry (T.G.) were carried out by means of the Derivatograph. On the recordings of the thermal analyses, it is possible to recognize the thermal behaviour of particle constituents. Reduced co-pies of optical recordings are shown in the figures 3 and 4.

The Dogger samples show several exothermic and endothermic reactions as follows: 1) Thermal dissociation of siderite.

2) Oxidation of Fe^-i- Fe^-i-. 3) Dehydroxyllation of clay minerals. 4) Thermal decomposition of calcite.

Thermal dissocation of siderite (FeCOj - FeO + COj) is an endothermic reaction, however immediate oxidation of FeO into FegOj is a strong exothermic reaction. Re-leased energy will be consumed for siderite decay so that several exothermic peaks occur within the range of 400°C-700°C at the D.T.A.-curves (figure 3, 4).

At 500°C-550°C clay minerals will dehydroxyllate (kaolinite and illte). It overlaps with the siderite decay. On the other hand all the above mentioned reactions are accompa-nied by loss of weight. CO2 and H j O releases result in a substantial reduction of the sample weight. Maximum weight loss because of ignition was observed on sample W-11-9 (27.1%). This huge mass change overlaps the mass change caused by oxidation of FeO to FejOg. Intake of oxygen leads to an increase of weight proportional to the iron content. Only a slight mass inncrease is recognizable on the samples W-ll-9 and W-l-4a (figure 3, 4).

Sample W-0-29 also contains a substantial quantity of calcite ( ± 2 0 % ) . It has not been recognized in other D.T.A.-analyses. Thermal dissociation begins after decomposition of siderite and dehydroxyllation of clay. These reactions culminate at 845°C. They are followed by exothermic reactions of a phase transformation from kaolinite to pseudo-mullite at 905°C without a change of mass. The sample finally shows a weight-loss of 2 0 . 2 % because of ignition. The original grey coloured sample becomes purple due to the formation of haematite from siderite.

Other Dogger-samples only contain siderite as a carbonate. Their paths of thermal de-composition are different. Weight-loss because of ignition within the range of 400°C-700°C, indicates the presence of siderite, however its quantification is ruffled by clay-dehydroxyllation.

X.R.D.-results (table 2)

The X.R.D.-analyses of some of the Dogger samples show a constant mineral compo-sition. All samples show the presence of quartz, alkali feldspar, siderite, muscovite/illi-te, chlorite and kaolinite. The samples from the W 0-series also contain a high percen-tage of calcite, which is sporadically present in the other series (table 2). The phosphate-minerals are not recognizable in the X.R.D.-analyses. The cause might be the cryptocrystaline character of the apatite (Collophane) or the presence of abundan-ce of siderite. The latter has the main-line at the same plaabundan-ces as apatite.

Table 2: The mineral content of some of the Dogger samples, obtained by X-ray dif-fraction. Sample nr. Mineral name W 0-27 W 0-29 W 1-1 W l-3a W 11-5 W 11-6 W 11-8 Quartz + + -1- + + + + + + + -1- 4 - + + Feldspar + + + + + -1- + Muscovite/lllite + ± ± ± ± ± ± Kaolinite + + + + + -1-Chlorite + + + + + + + Siderite + + + + + + + + + -1-Calcite + + - H +

W 0-27 : Sandstone Bottom Dogger, W 0-29 : Main sandstone B Dogger, W 1-1 : Top Dogger layer C,

W l-3a : Bottom Dogger main sandstone B.

W 11-5 W 11-6 W 11-8

Top layer D Dogger, Top layer C Dogger, Main sandstone layer B Dogger,

S.E.M. Results (photo 7 to 13)

Scanning Electron Microphotographs gave an impression of the relationship between detrital and authigenic phases, to mention:

• ) The corrosion of quartz grains in the siderite matrix (photo 7, 9).

•) The structure of collophane grains. The cryptocrystalline state causes conchifor-med fracturing (photo 10, 11).

•) Weathering of Alkalifeldspar often gives formation of kaolinite-booklets (photo 12,

13).

• ) The siderite spherulites have a build up of concentric layers (photo 8) in a carbon-ate rich groundmass.

CONCLUSIONS

The petrology of the Dogger Formation at the east-cliffs, between Whitby harbour and Saltwick Nab, show a lateral variability in thickness and composition. Even on a small scale, as seen at Long Bight, this variability is present and pronounced in proportions between co-existing minerals.

The red colour of top layers C and D is caused by partial oxidation of siderite in haema-tite in the sedimentary environment. Subaerial conditions resulted into the red colour and possibly the inhomogeneous layering of the Top layer C and D. The grey colour of Dogger is diagnostic for shallow water filled depressions and basins. D.T.A. and X.R.D. results of the parts, where the top layers C and D are absent, show primary cal-cite in the mineral composition besides siderite.

(7)

Some samples suggest effects of volcanic activity, for instance:

• ) Tfiese rocks are higtily cemented and contain angular fragments of fiigti tempera-ture minerals. Tfiese alkali feldspar grains are often unaltered or partly altered in presence of fully altered feldspar in general.

•) Tfie Dogger Formation is a product of uplift (block movement, erosion and sedimen-tation in shallow water during Toarcian and Bajocian time. Middle Jurassic Volca-nism might be the origin of these pyroclasts.

Charcoal relicts are residues of bush fires. All remnants are fragments, replaced due to the complete reworking of Dogger sediments. Due to the high charcoal content of these sediments, it is thought that these were deposited in the vicinity of a non-marine environment.

RECOMMENDATIONS FOR FURTHER RESEARCH

The preliminary results clearly show that the usual and new techniques are required to obtain more mineralogical and chemical information. Presently trace-element analy-ses on samples of the Dogger Formation and adjacent layers are being performed. New X.R.D./D.T.A. analyses, microprobe analyses and thin sections are expected to give more information about the spatial distribution of minerals and elements.

ACKNOWLEDGEMENT

This research was undertaken with financial support of the Stichting Molengraaf Fonds en Het Fonds voor de Wetenschappen. I should like to thank the following: A. van Dijk for preparing thin sections, R. Ephraim who made the photos of the thin sections. Soil Mechanics Delft for their D.T.A. and T.G. analyses and Prof. ir. K. J . Weber and Dr. F. Koster for suggestions and the valuable discussions.

calcite matrix.

of calcite and siderite.

(8)

Figure 3: D.T.A. and T.G. graphs of Dogger samples. W 0-28 : Top Dogger sandstone (layer B). W 11-9 : Siderite concretion.

W III-14B: Shale on the Dogger/Lias boundary.

Figure 4: D.T.A. and T.G. graphs of Dogger samples. W I-2A : Top Dogger (layer 0 ) .

W l-4c : Shale on the Dogger/Lias Boundary. W l-4a : Siderite concretion.

(9)

38

Photo 8: Scanning Elec-tron Microphotograph. Siderite spherulites. The concentric layering is clearly visible.

(10)

Photo 9: Scanning Electron Microphoto-graph. A detail of a corroded quartz grain in contact with the siderite matrix.

Photo 10: Scanning Electron Microphoto-graph. A collophane nodule (crypto-crystalline apatite) in contact with the si-derite matrix.

graph A

deZrof

J r T H ^'^""'"^ ^'^'^^^^

Microphoto-contact On I t H, '=^"°P^^"^/^"^^rite graph. A detail ot fully weathered and au-JkTfLsoIr orT^^^^ 'cf'oj'o.p/.c thegenic altered feldspar Booklets of sub-aikah-feldspar gram is recognizable. parallel kaolinite crystals have grown

Photo 13: Scanning Electron Microphoto-graph. Progressive kaolinitization of alkali-feldspar.

140

REFERENCES

Arkell, W. J . : The Jurassic system in Great Brittain. 1933, Clarendon Press, Oxford. Ashton, M.: Carbonate tidal rhythmites from the Middle Jurassic of Brittain. Sedimeto-logy, 1981, vol. 28, 689-698.

Bate, R. H.: The Yons Nab of the Middle Jurassic of the Yorkshire coast. Proc. York-shire Geol. S o c , 1959, Vol. 32, pp 153-164.

Bennison, G. M., Wright, A. E.: The geological history o f t h e British Isles. (1978). Chap-ter 13, pp 285-305. Edward Arnold Publishers Ltd.

Brumhead, D.: Geology explained in the Yorkshire dales and on the Yorkshire coast. (1979) pp 110-154. Newton Abbot, London - North Pomfret (VT).

Donovan, D. T., Jones E. J . W.: Causes of world wide changes in sea level. J . Geol. Soc. London, Vol. 136, 1979, pp 187-192.

Fall, H. G. e.a.: Jurassic, volcanic rocks of the Northern North Sea. J . Geol. Soc. Lon-don. Vol. 139, 1982, pp 277-292.

Fisher, M. J . Hancock, N. J . : The Scalby Formation of Yorkshire; reassessment of age and depositional environment. Proc. Yorkshire Geol. S o c , vol. 45, 1985, pp 293-298. Fleet A. J . e.a.; The rare earth element geochemistry of glauconietes and celadonites. J. Geol. Soc. London. Vol. 137, 1980, pp 683-688.

Gluyas, J . G.; Early Carbonate diagenesis within phanerozoic shales and sandstones of the N-W European shelf. Clay Minerals (1984) 19, pp 309-321.

Hancock, N. J . , Archer, J . S.: North Sea Jurassic Reservoirs; an integrated field cour-se in geology and recour-servoir engineering. Robertson Recour-search International Ltd. Heckel, P. H. ecognition of ancient shallow marine environments, in; Recognition of ancient sedimentary environments. 1972, pp 226-287. A special publ. of the Soc. of economic paleonthologists and mineralogisitho.

Hemmingway, J . E., Knox, R. W. O'B.: Lithostratigraphical nomenclature of the Middle Jurassic Strata of the Yorkshire Basin of North-East England. Proc. of the Yorkshire geol. S o c , 1973, Vol. 39, pp 527-535.

Irwin, H., Curtis C ; Isostopic evidence for source of diagenetic carbonates formed dur-ing burial of organic-rich sediments. Nature, 1977, vol. 269, pp 209-213.

Kantorowicz, J . D.: The petrology and diagenesis of Middle Jurassic sediments Ra-venscar Group, Yorkshire. Sedimentology, 32, (1985), pp 833-355.

Kantorowicz, J . ; The nature, origin and distribution of authigenic clay minerals from Middle Jurassic Ravenscar and Brent Group Sandstones. Clay Minerals (1984), 19, pp 359-375.

Kent, P. E.; Review of the North Sea Development. 1975, J . Geol. S o c , vol. 131, pp 435-467.

Kent, P. E.: Subsidence and uplift in east Yorkshire and Lincolnshire; a double inversi-on Proc. Yorkshire Geol. S o c , 1980, Vol. 42, pp 505-524.

Knox, R. W. O'B.; Lithostratigraphy and depositional history of the late Toarcian se-quence at Ravenscar. Yorkshire. Proc. Yorkshire Geol. Soc. 1984, Vol. 45, pp 99-108. Leeder, N. M., Nami, M.; Sedimentary models for thenon-marine Scalby Formation and evidence for late Bajocian/Bathonian uplift of the Yorkshire Basin. Proc. of the Yorkshire Geol. S o c , 1979, vol. 42, pp 461-482.

(11)

„Seit mehr als 90 Jahren lösen wir weltweit die kompliziertesten Bauauf galien -seit mehr als 80 Jahren sind wir auch für den Bergbau tatig"

Uber 8O00 Mita*eiler haben Heakamp zu einem der groBen deul-schen Bau- und Bergbau-Spezialunternerimen gemacht Unsere Dienstleistungen tur den ESergbau unler Tage umlassen den kon-venlionellen und maschinellen Slreckenvonrieb, Das Herstellen von Groflraumen, den Schachtbau, Ankerungs- und Gebirgsverte-siigungsartseiten, das Rauben von Strecken und Streben Aufwal-tigungs- und NachnfJarbeiten sovwe den Gleisbau.

A HEITKAMP

Livera, S. E., Leeder, M. R.: The Middle Jurassic Ravenscar Group of Yorkshire: re-cent sedimentological studies as demonstrated during a field meeting, 2-3 may 1980. Proc. Geol. Ass. 92 (4), pp 241-250.

Marshal. J . D.: Zoned calcites in Jurassic ammonite chambers: trace elements, isoto-pes and neomorphic origin. Sedimentology (1981), 28, pp 867-887.

Morris, K. A.: Comparison of major sequences of organic-rich mud deposition in the British Jurassic. J . Geol. Soc. London, 1980, vol. 137, pp 157-170.

Notholt, A. J . G.: Phosphatic and glauconitic sediments. J. Geol. Soc. London, 1980 pp 657-659.

Petroleum geology of the Continental Shelf of North-West Europe. Inst. of Petroleum, 1981.

Hancock, N. J . , Fisher, M. J . : Middle Jurassic North Sea Deltas with particular referen-ce to Yorkshire. (Chapter 16). pp 186-195.

Eynon, G.: Basin development and sedimentation in the Middle Jurassic of the Nor-thern North Sea.

Parry, C. C. Intergartion of palynological and sedimentological methods in facies ana-lyses of the Brent Formation.

Powel, J. H.: Lithostratigraphical nomenclature of the Lias Group in the Yorkshire Ba-sin. Proc. of the Yorkshire Geol. S o c , Vol. 45, 1984, pp 51-57.

Parson, C. F.: A stratigraphic revision of the Scarborough Formation (Middle Jurassic) of North-East Yorkshire. Proc. Yorkshire geol. Soc. Vol. 4 1 . pp 203-222, 1977. Purser, B. H.: Syn-sedimetary marine lithification of Middle Jurassic Limestones in the Paris Basin. Sedimentology, 12 (1969) pp 205-230.

Rayner, D. H., Hemingway, J . E.: The geology and mineral resources of Yorkshire. (1974); pp 161-163, 172-174, 178-189, 202-203.

Parker, J . R., Lovelock, P. E. R.: Field Guide to the geology of the North-East York-shire coast. (1974), Shell U.K. Exploration and Production Ltd. London.

Cytaty

Powiązane dokumenty

To calculate the total volume of monthly import and export of shipments in each branch, in spreadsheet „calculations” (table 3) the values of supply and demand

Therefore, to reduce the communication costs of the DDSB, we first proposed a clique-based gossip algorithm, and then we presented the CbDB algorithm based on the principle

a) Klaster w formie łaĔcucha wartoĞci dodanej – klaster stanowią przedsiĊ- biorstwa sąsiadujące w łaĔcuchu wartoĞci dodanej; zasadnicze znaczenie mają w tym

M łodszą m etrykę (przełom epoki brązu i żelaza) m ają naczynia, na których pojaw iły się oprócz w yraźnych żłob­ ków także odciski stempelka, oraz naczynie z ornamentem

Zauważmy jednak, że jeżeli nieskończenie dobry (w powyższym znaczeniu) Bóg jest przy tym stwórcą świata i że stworzył świat we- dług własnej woli, a zarazem w świecie

kupcy z Eastland Company mieszkający w Londynie skarżyli się w liście do swych towarzyszy z Yorku, że obserwują wzrost aktywności interlopersów oraz

TER VERKRIJGING VAN DE GRAAD VAN DOCTOR IN DE TECHNISCHE WETENSCHAP AAN DE TECHNISCHE HOGESCHOOL TE DELFT, KRACHTENS ARTIKEL 2 VAN HET KONINKLIJK BESLUIT VAN 16 SEPTEMBER 1927,

designers and planners improve urban resilience?» and discusses «To what extent is Big Data necessary in addition to current knowledge and practices of resilience building?»