North Foreland Research Articles

The role of the Bay of Biscay Mesozoic extensional structure in the configuration of the Pyrenean orogen: Constraints from the MARCONI deep seismic reflection survey

Seismic interpretation of the MARCONI deep seismic survey enables recognition of the upper crustal structure of the eastern part of the Bay of Biscay and the main features of its Alpine geodynamic evolution. The new data denotes that two domains with different Pyrenean and north foreland structures exist in the Bay of Biscay. In the eastern or Basque‐Parentis Domain, the North Pyrenean front is located close to the Spanish coast, and the northern foreland of the Pyrenees is constituted by a continental crust thinned by a north dipping fault that induced the formation of the Early Cretaceous Parentis Basin. In the western or Cantabrian Domain, the North Pyrenean front is shifted to the north and deforms a narrower and deeper foreland basin which lies on the top of a transitional crust formed from the exhumation of lithospheric mantle along a south dipping extensional low‐angle fault during the Early Cretaceous. The transition between these two domains corresponds to a soft transfer zone linking the shifted North Pyrenean fronts and a north‐ to WNW‐directed thrust that places the continental crust of the Landes Plateau over the transitional crust of the Bay of Biscay abyssal plain. Comparison between this structure and regional data enables characterization of the extensional rift system developed between Iberia and Eurasia during the Late Jurassic and Cretaceous and recognizes that this rift system controlled not only the location and features of the Pyrenean thrust sheets but also the overall structure of this orogen.

Iodargyrite from Zalas (Cracow area, Poland) as an indicator of Oligocene–Miocene aridity in Central Europe

Iodargyrite, the hexagonal silver iodide, was found in the Permian rhyodacite quarry at Zalas (near Cracow, Southern Poland) in a fault zone cutting Middle Jurassic sandy limestone. It occurs within a tectonic breccia encrusted by chalcopyrite, pyrite, Ag-containing chalcocite, covellite, galena, native bismuth, malachite, cuprite, Fe- and Mn-dominant oxides, Cu sulfates and barite. The hydrothermal encrustacion is most likely connected with rejuvenation of Old–Paleozoic faults in the Sava phase of the Alpine orogeny on the Oligocene–Miocene boundary. The periods of aridity when iodargyrite precipitated, determined by evaporation of salt lakes or the inland Miocene sea that delivered halide ions to the groundwater oxidation system, or leaching of weathered Ag-containing mineralization by saline, I −-rich deep formation waters derived from Paleogene sediments during folding and formation of the Carpathians nappe structure, are connected rather with the Low to Middle Miocene period. At this time, steppe areas with a dry climate existed on the north foreland of the Carpathians in southern Poland as a result of a displacement to the north of a dry subtropical zone because of uplift of the Carpathians and regression of the inland Miocene sea.

Wave coupling between the Tianshan orogen and the deformations in its south and north foreland basins in Cenozoic

Attention has been paid to the deformations in the south and north foreland basins of the Tianshan Mountains and their relations to the tectonic movements of the mountains. Based on the seismic data interpretation and field work, the tectonic features, tectonic styles, controlling factors of deformation, deformation time, and their relationships in the three tectonic units were comparably studied. The Cenozoic deformations in the two foreland basins were characterized by zonation from south to north, segmentation from west to east, and layering from deep to shallow. The tectonic styles are compressive ones, including both basement-involved and cover-detaching. The two foreland basins underwent several times of deformation in Cenozoic and the deformations were transmitted from the Tianshan orogen to the inner basin. The deformation dynamics of the south and north foreland basins of the Tianshan Mountains can be represented by dynamics of orogenic wedges. In terms of the deformations of the wedges with wave-like features, the concept of a wave orogenic wedge was put forward, and a double wave orogenic wedge model was established.

Mesozoic fill-sequences in Hefei Basin: Implication for Dabie Orogenesis, central China

A research on the Mesozoic fill-sequences of Hefei basin, located at the north foot of Dabie Mountains, shows two-phase evolution. The first phase, early- to mid-/late-Jurassic, is characterized by terrestrial clastic deposits, with four times of reverse-grading units at least, and forms greatly thick molass reconstruction in the mid-/late-phase, which reflects gradually strong thrusting-orogenesis in the north Dabie and flexural depression in the north foreland of Dabie Mountains. The second phase, late-Jurassic to Cretaceous, includes two-episode rifting processes. The first episode (J3) shows calc-alkalic and alkali volcanic rocks interstratified pyroclastic rocks, which may reflect upwelling igneous magma from mantle-source due to the Yangtze continent slab breakoff induced by deep subduction process. A suite of lacustrine, fluvial and piemount facies, about 3000 –3500 m in thickness, develops in the second episode (J3-K1), which reflects regional extensional setting and intense elevator diversity of mountain-basin in the study area. This research renews and deepens cognition for the Mesozoic Dabie orogenesis

A Male genital defect in the dog-whelk, Nucella lapillus (Neogastropoda), favouring survival in a TBT-polluted area

Tributyltin (TBT) pollution has exterminated populations of the dog-whelk Nucella lapillus along most of the north Kent coast (Thames Estuary) but the species survives as a small enclave around the North Foreland. Males in this enclave exhibit an unusual defect involving the non-development or partial development of the genital system: about 10% lack penes, or have undersized penes, and their gonoducts (vas deferens and prostate) are incompletely developed; in some cases, spermatogenesis appears to be retarded. Laboratory-bred animals display the same characters. This deficiency (‘Dumpton Syndrome’) is manifest also in the atypical development of male sex organs on the females (‘imposex’) induced by exposure to tributyltin (TBT). The evidence points to Dumpton Syndrome being a genetic disorder which has lessened the sterilizing effect of imposex and thereby has permitted the survival of this isolated enclave in an area of high TBT pollution.

Photographic evidence of rate of development of plant cover on the emergent island Anak Krakatau from 1971 to 1991 and implications for the effect of volcanism

Photographs of the vegetated North and East Forelands of Anak Krakatau, which emerged from the sea in 1930 and was totally devastated by volcanic activity in 1952/53 provide some evidence of rate of change of plant cover from grassland to woodland between 1971 and 1991. The series of photographs demostrate that vegetational stages of the two forelands have not been synchronous and suggest that the North Foreland is lagging the East Foreland by about 12 years.

The arrest and imprisonment of Henry Oldenburg

In the month of June, 1667, there was great alarm and disquiet in England at the turn of events in the war with Holland. Enemy fleets, Dutch and French, were off the coasts and outward-bound merchantmen put back for safety into the Thames and into Dover and Sandwich. All news of the English Fleet was censored. On June 7 the Dutch ships were off the North Foreland. The militia was armed and a chain-boom was constructed across the Medway above Gillingham to protect the warships anchored upstream. The Dutch set fire to houses and barns on Canvey Island. On June 11 Sheerness and the Isle of Sheppey were attacked and Sheerness was taken. Next day, disaster and a disgrace that is still remembered fell upon the Fleet. The chain-boom in the Medway was forced by the Dutch, who sailed up the river, burnt some of the finest vessels in the Fleet and captured the Royal Charles , the largest ship in the Navy up to that time, fitted for 100 cannon and mounting 30 guns. The pride of the Navy was sent to Holland as a trophy. However, bad as affairs stood, further attempts by the Dutch on the ships in the Medway during the next two days were successfully beaten off.

The Deverel Urn and the Picardy Pin: A Phase of Bronze Age Settlement in Kent

In March 1929, foundations were being dug for the new Biological Laboratory at St. Lawrence College, Ramsgate, overlooking the coast of Thanet, 4 miles SSW. of the North Foreland. In the course of digging, the workmen came across an ancient excavation in the chalk rock, lying beneath several feet of humus and filled with earthy chalk rubble. Intact in this excavation was a hand-made pottery urn (fig. 1, and pl. v, 1), and inside the urn were three large pins of cast bronze (fig. 2, 1–3). The earthy chalk rubble also contained a small number of ancient animal bones and teeth, and shells of the common sea mussel. The discovery was witnessed, and the finds were collected, by Mr C. E. Baldwin, M.A., then Senior Science Master at St. Lawrence College. The urn, extracted in fragments, was subsequently identified as a Bronze Age vessel by the late Mr J. E. Couchman, and the pins were recorded by Miss Lily F. Chitty in the British Association Card-Catalogue of Bronze Age Implements. In 1939 Mr Baldwin, now Headmaster of the County School, Camberley, Surrey, kindly consented to submit the finds for examination by the present writer in the British Museum, and permitted their subsequent exhibition (the urn restored) to the Prehistoric Society, and their publication here.

Some Notes on the Plankton of the Thames Estuary

THE precise limits of the estuary of the River Thames are not easy to define. The Thames Conservancy's eastern limit (Crowstone to Yantlet) is generally acknowledged as forming the end of the river itself, although, geographically and physically, the head of Sea Reach makes a more satisfactory boundary. The western limit, however, is the subject of some controversy. The jurisdiction of the Port of London Authority extends to the meridian of Havengore Creek and for Custom's purposes the Estuary extends to a line drawn from Reculver Towers on the Kent coast to a point just below Clacton-on-Sea on the Essex side. A glance at the chart of the area in question (Fig. 1) will show that the typical estuarine sandbanks continue some miles farther eastward. For this reason, doubtless, Captain Tizard, R.N. in his Hydrographical Surveys in the Triton, 1882-9, gives the eastern boundary as being a line from the North Foreland, Kent, to Harwich, Essex, via the Kentish Knock Lightvessel (Fig. 2). The Company of Free Fishermen of the River of Thames', and indeed all ruling bodies of that river since Norman times, also gave the aforementioned line as the limit of their jurisdiction and for the purposes of this paper that limit will be assumed. The Second Ice Age, it is generally agreed, was responsible for the present peculiar formation of the Estuary. The north-east trend apparently results from the course of the river, when, with the Rhine, it flowed (supposedly) through what is now the North Sea. The supposition is that with the rapid

Discussion on “The performance of a radio-telegraphic transmitter, with special reference to the new installation at North Foreland”

Discussion on “The performance of a radio-telegraphic transmitter, with special reference to the new installation at North Foreland”

The performance of a radio-telegraphic transmitter, with special reference to the new installation at North Foreland

The paper deals with the performance of a commercial type of l½-kW spark transmitter. The electrical quantities in the various circuits are discussed, and experimental results are given which enable a complete analysis of the losses to be arrived at. Particulars of the performance of this type of installation under traffic conditions show that the type of signal emitted gives high commercial efficiency.

On the Chalk of the Isle of Thanet

Introduction .—Besides Professor Morris's account of the faults in Pegwell Bay* the only note on the Chalk of the Isle of Thanet that I can find is by the late Rev. W. D. Conybeare, who says,“The north- eastern cape, called the North Foreland, forms the loftiest point (of the cliffs)* * * between this point and Margate the lowest strata are exhibited, the Chalk without flints making its appearance: hence the strata gradually decline, though under an imperceptible angle, towards the south-west, in which direction the upper beds of the Chalk sink and disappear beneath the more recent formations†.” Unfortunately this, which, as far as I know, has never been contradicted, is in groat part the reverse of the truth, as I found whilst carrying on the Geological Survey in East Kent in 1863; for there is no “Chalk-without-flints” in the island, the comparatively flintless Chalk of Margate is above the more flinty Chalk of Broadstairs, and the beds rise southwards at first, toward the middle part of the island, though they afterwards sink again further in the same direction: the island is in fact a very flat arch (or perhaps the half of a dome, of which the eastern part has been worn away by the sea), as shown by the section. The late Mr. P. J. Martin noted the fact of the Isle of Thanet being an elevated mass of the Chalk*. The higher division, or, as it may fitly be called, The Margate Chalk , contains but a very

Some observations on the peculiarity of the tides between Fairleigh and the North Foreland; with an explanation of the supposed meeting of the tides near Dungeness

After adverting to the circumstances upon which the generally adopted opinion is founded, that the tides meet between Dungeness Point and Rye Harbour, Captain Anderson describes the peculiarity of the Channel at that point, and its very sudden contraction between Dungeness and Cape D’Alprèe, and between the South Foreland and Calais Point; so that the western tide meets with a resistance to its course at Dungeness and Cape D’Alprèe; where, from the passage being insufficient to discharge the water brought from the westward, it must accumulate until it deepens and widens the Channel, so as to become adequate to the discharge of the water. The peculiarities of the rise and fall of the tides at adjacent places, is referred by the author principally to the accumulation that takes place in these basins. That the tides do not meet at Dungeness in a line across the Channel, is further proved by the absence of that violent concussion of water which in such a case would ensue; the fact being, that the formation of the coast by gradually altering the course of the tide between the South Foreland and buoy of the Nore, from E. N. E. to W. N. W. within the stream of the Goodwin Sands, occasions a gentle blending of the waters, so that there is only a strong eddy about the Kentish Knock, and a foamy rippling where they meet and proceed onwards together.

XV. Some observations on the peculiarity of the tides between Fairleigh and the North Foreland; with an explanation of the supposed meeting of the tides near Dungeness

Having observed that several Charts and Books of Navi­gation assert, that the tides from the North Sea and the Channel, or the Eastern and Western tides, meet in the vicinity of Dungeness and Rye harbour ; and that, on such authority, this opinion has been too generally adopted by those, who have not had the opportunity or the inclination of making personal observations ; as well as by the pilots on this part of the coast, who from being incapable, for the most part, of making observations or deducing inferences from facts before them, readily embrace the first theory they meet with in print , however erroneous or inconsistent ; I have been induced to bestow all the attention in my power to the phænomena of the tides between Fairleigh and the North Foreland, and now venture to submit the result of my observations to the notice of the Royal Society. From having cruised constantly within these limits for nearly two years and a half, I have had many opportunities of making observations ; but I must, nevertheless, profess my readi­ness to admit any alteration or improvement which may be pointed out by those more conversant with the subject; truth alone being the object of my enquiries.