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Field Trips which took place in 2009
Sat.
May 30th
09: Berwick
Town Shoreline. Leader
- Dr. Ken Patterson.
About 12 people made a traverse along the shore examining Lower
Carboniferous rocks of the Middle Limestone Group within the Tweed
Basin, from the Meadow Haven Fault to the Green's Haven Fault to the
north. This stretch of coastline illustrates some spectacular
examples of structural geology in a relatively small area, namely a
series of domes, e.g. Ladies Skerrs dome, basins (Bucket
Rocks) and faults. The cliff exposure of the Green's Haven
Fault (click here for a
photo) was especially remarkable with regard to the contrast
between the well bedded shales on the downthrow side and the massive
sandstone on the upthrow. The shales adjacent to the fault plane were
upturned, clearly indicating which side was the downthrow. All the
aforementioned structures owe their origin mainly to Carboniferous
crustal extension (back-arc extension?) and pre-Carboniferous geography.
Interesting sedimentary structures and rock successions typical of
Yoredale cyclothems were also demonstrated. At least two localities
displayed a typical cyclothem of limestone, mudstone/siltstone,
sandstone, seatearth (often stained yellow by the mineral jarosite)
and a thin coal. Typical fossils were also discovered (corals such as
Lithostrotion sp., Dibunophyllum, brachiopods and bivalves). Abundant
examples of the trace fossil, Zoophycos with its typical horizontal
swirling pattern were seen and discussed as to their origin. They are
thought to be the feeding burrow systems of a worm-like organism.
Many thanks to
Ken for making it such an enjoyable day.
(Back to Field Trips page.)
Sun.
June 28th 09: Burniston
Dinosaur Footprint Beds: Leader: Dr.
Martin Whyte, Sheffield University.
Our
membership secretary has made a more comprehensive report which can
be accessed HERE. A
party of 10 members met at 10.30 am at Grid Ref. TA0255 9360
(Crookness), i.e. near end of the minor road which goes
northeast then south east from "The Jolly Sailors Pub"
in Burniston. The small road is called 'Rocks Lane' and is
sign-posted as that by the pub. We then proceeded to Burniston steps
which lead to the shore. Immediately to the north of the steps is the
well known Burniston Footprint Bed forming an overhang towards the
top of the cliff. Fallen blocks from the Bed displayed tridactyl foot
prints as well as trace fossils. The party proceeded towards Cromer
Point. During the traverse, a series of offset sandstone/siltstone
beds dipping in a curvilinear direction were observed. They are
interpreted as lateral accretion (point bar) deposits formed on the
inside bends of migrating river channels.
As the party made its way northwards a complex of channel sandstones
and lateral accretion deposits, some superimposed on each other, were
observed. A loose block, no doubt from one of the beds of dark
carbonaceous clay, was seen to contain a mass of spherules which
consisted of sphaerosiderite. Carbonaceous clay showing intense
sideritisation indicates a palaeosol horizon, i.e. a "fossil
soil" which formed a swamp like environment. Towards Cromer
Point, metre long scour channels (gutters) were observed in sandstone
on the underside of a cliff overhang. They are thought to have been
formed by a tidal surge during a brief marine episode. Perhaps one of
the highlights of the day was examining a huge print of a sauropod
protruding from a the cliff near Long Nab. Our leader also pointed
out other interesting sedimentary features, some of them enigmatic.
For some photo's, click here.
Thin sections of the carbonaceous siderite clay were made. Click
here to view them.
(Back to Field Trips page.) Many thanks to Martin for making it
such an enjoyable day.
Sat.
July 25th 09: Title:
"Hot and even Hotter!" A new
look at the Whin Sill intrusion. Recent research on the
Low/High Force area. Leader: Dr. Stuart Jones.
For
a full report by our Membership Secretary, click
here. A party of about 10 members and
friends met at Bowlees car park. From here the party proceeded to Low
Force where Dr. Stuart Jones demonstrated the contact between
Carboniferous sandstone and the underlying Whin Sill. A series of
horizontal drill cores at measured distances from the contact had
been made in order to determine the effect thermal contact with the
Whin Sill had had on the porosity and permeability of the
overlying sandstone.
The party then proceeded to the Whin Sill "raft" near
Wynch Bridge where Dr. Jones demonstrated how drill cores had been
made on sandstones below the Whin Sill, (sub-igneous profiling).
Similar results had been obtained. Interestingly, one of the
horizontal cores had cut into the actual whin sill-sandstone contact
which was well seen.
The research concluded that porosity and permeability was reduced
only by about 40cm from the contact due to the introduction of clay
minerals (illite and/or kaolinite) derived from altered feldspars
from within the igneous intrusion. This research would be of
relevance when prospecting for potential hydrocarbon reservoir rocks
since igneous intrusions are clearly indicated on seismographs.
Therefore it is advisable not to sink boreholes near igneous intrusions.
After
thanking Dr. Jones for such an interesting day, some of the party
proceeded to High Force where similar research had been carried out.
For some photo's, click here.
Sun.
Aug. 9th 09: The Permian back-reef / reef
transition and Quaternary. Leader: Dr. Eric Johnson.
For a full report by our Membership
Secretary, click here.A
party of 15 members and friends met at the Natural England Castle
Eden Dene Information Centre - Oakerside Lodge [NZ 427 393] off
Stanhope Chase, Peterlee at 11.00am. From here the party proceeded
into Castle Eden Dene, a steep sided pre-glacial valley re-excavated
by melt waters at the end of the last ice age. The first stop was at
Gunners Pool Bridge which crosses a very narrow and deep gorge cut by
the Castle Eden Burn. The straight course of the Burn in this
locality follows the course of an east-west trending fault, downthrow
to the south, which cuts into the rocks of the Ford Formation, bedded
dolomite back-reef facies, (formerly Middle Magnesian Limestone).
Vertical fractures within the line of the fault were observed. Reef
facies exposures were then examined at "The Devil's
Lapstone", and "The Kissing Frogs" fallen blocks of
magnesian limestone. All displayed a typical massive unbedded reef
structure. Faint traces of possible fossils were observed.
Recent landslips were also observed during the traverse, evidence of
which was either a lack of or a difference in vegetation. Lunch
was taken in a dry stream bed where erratics of fossiliferous
Carboniferous Limestone, ?Whin Sill quartz dolerite and ?Cheviot
granite were examined.
The party then drove to Shippersea Bay to examine the "Easington
Raised Beach", (NZ4434 4537). With care, some descended the
cliff to the exposure. A calcreted gravel interspersed with lenses of
finer consolidated sand, lying on a Magnesian Limestone rock platform
at about 32m above sea level was observed. The gravels were seen to
contain an abundant modern-type marine shell fauna. According to
Smith & Francis, 1967, a radiocarbon minimum age estimate of
38,000 years BP was obtained. According to Bowen and Sykes,1988
and Bowen et al., 1991, tests indicated an oxygen isotope stage 7,
i.e. about 200,000 years BP, (a temperate stage known as the
"Ilfordian"). A.G.Lunn states that this presents a problem
in so far as sea level 200,000 BP should have been about the same as
today. Lunn, in A.G. Lunn, Robson's Geology of North East England,
ed. G.A.L. Johnson, Trans. Nat. Hist. Soc. Northumbria Vol.56 pt.5,
1995, states "the altitude of the raised beach presents a
difficulty in that interglacial global ice volumes, and therefore
glacio-eustatic sea levels, should have been much as now; the beach
may perhaps have formed before complete isostatic recovery of the
land after a previous glaciation."
The party then made their way along the coastal path back to the car
park where the leader was thanked for a very interesting and
informative day. For some
photo's, click here.
Sun.
Sep. 6th 09:Title: "A
fluvial conundrum- Pinglehole Syke plus the development of the
Silurian - Devonian - Carboniferous geological activity of Saughtree,
Roxburgh" Leader: Gordon
Liddle. A video of this field trip,
produced by BBC Look North, can be downloaded by clicking on the
following URL: http://news.bbc.co.uk/1/hi/england/8920195.stm
A party of seven members and guests met on a rather grey morning at
the side of the B6357 at NY 556962 some 1 mile SW of Saughtree
village in Liddlesdale. After walking a few hundred yards up the side
of Pinglehole Sike, a fine view was had of the surrounding
countryside and Liddel Water coursing south west through Liddlesdale,
a former wide glacial drainage channel. The party progressed uphill,
noting the southward coursing deeply incised channel of Pinglehole
Sike with zigzaging alternating spurs cut into a succession of Lower
Carboniferous thin limestones and shales dipping gently in an
easterly direction. No doubt the alternating spurs were due to the
stream encountering the differing resistance of harder limestones and
softer shales. The leader pointed out evidence of a cycle of erosion,
a model for stream erosion and landscape development proposed by
Davis in the 19th C. defining a young, mature, and old sequence in
the development of a river valley. The model, as the leader
emphasised, has to some extent been heavily modified by developments
during the plate tectonics revolution in the 1960’s and 70’s.
The party then proceeded in a northwesterly direction to an old
railway cutting (Palmer‘s Hill Cutting), examining, en route,
local erratics of limestones, shales, vesicular volcanic rocks and
Devonian sandstones. Springs emanating from adjacent to the cutting
made the ground very soft and muddy. However, the difficult walking
was rewarded by a spectacular unconformity exposed to the north of
the cutting where a series of alternating steeply dipping and folded
shales and greywackes underlying near horizontal Devonian rocks were
observed. The leader remarked on the huge forces which caused the
folding and the enormous time gap which existed between the
deposition, deformation and erosion of the Silurian sediments and the
emplacement of the near horizontal Devonian rocks. Flute casts
at the base of some of the Silurian beds were examined from which the
original current direction could be determined.
A return was then made to Pinglehole Sike proceeding downstream
close to the channel where various features of a stream or river were
examined, e.g. imbricate structures and ways in which bedloads are
transported. As the stream approached more level land it was noticed
how a meander developed through alluvial floodplain deposits. A
former oxbow lake, now infilled, as well as levee deposits were also noted.
On reaching the transport, our leader was thanked for a very
interesting, informative and enjoyable day.
Please
click here for photographs of the field trip.
Sat.
Oct. 24th: Cyclothems,
mineralisation and landscape in Weardale. Meeting
point: in layby on N side of A689, immediately west of Westgate in
Weardale [NY906 381]. Walking distance: up to 4 miles along good
footpaths and minor roads. The walk included a traverse through
several excellent Carboniferous cyclothems within the Alston
Formation. Good sedimentary structures, depositional and
structural features were seen, together with important
mineralisation. The varied impact of these on the local
landscape were demonstrated. Leader
- Brian Young (It is
hoped to publish a fuller report in the near future).
