OR/14/066 Model datasets

Arkley, S L B, and Callaghan, E A. 2014. Model metadata report for the Culloden-Nairn GSI3D superficial deposits model. British Geological Survey Internal Report, OR/14/066.

The data used to develop the Forres model is described below. Some general caveats regarding BGS datasets and interpretations are:

• Geological observations and interpretations are made according to the prevailing understanding of the subject at the time. The quality of such observations and interpretations may be affected by the availability of new data, by subsequent advances in knowledge, improved methods of interpretation, improved databases and modelling software, and better access to sampling locations
• Raw data may have been transcribed from analogue to digital format, or may have been acquired by means of automated measuring techniques. Although such processes are subjected to quality control to ensure reliability where possible, some raw data may have been processed without human intervention and may in consequence contain undetected errors

Raw data

Raw data used to develop the Culloden-Nairn model include digital terrain models, borehole data, digital geological shapefiles, additional field observations and bathymetric data. All the data are located at:
W:\Teams\QES\QMMP\Data\MorayNessBasin_Data\GSI3D Great Glen to Moray Firth\CULLODEN-NAIRN Model\Data

Digital Terrain Models (DTM’s)

Two DTM’s were extracted for use with this model, NextMap and Bald Earth both at 50 m resolution. The Bald Earth DTM was chosen as the NextMap DTM had a tendency to show artefacts such as trees, which would distort the true ground surface. The Bald Earth DTM was stored as a TIN within the GSI3D workspace.

Borehole data

Borehole data were entered into the BGS corporate database, BGS Borehole Geology according to the project GVS. The borehole information was extracted via the Data Portal for the model area using interpreter ‘ECAL’ and in total there were 473 boreholes and trial pits within the model boundary. Figure 2. In order to capture some deep boreholes out with the project area a buffer zone was introduced to capture these boreholes, e.g. Dalroy boreholes 1, 2 and 3, drilled up to 50.43 metres in depth. Boreholes were generally hung according to the DTM used, however where the DTM was affected by artefacts, e.g. pylons, the boreholes were aligned with the contour values.

Figure 2 Location of boreholes (including field information data).

Field information data

Field data points providing information on the deposits and their thickness were compiled into Excel tables and converted into ‘.bid’ and ‘.blg’ files for use in the modelling. Two different sources of field data were used.

1. BGS report WA/93/28R (Merritt and Auton, 1993) contained natural sections which were recorded during field mapping in the 1990’s. The information from these sites was recorded into an Excel table with additional information added, that is lithology, lithostrat and a GVS code for use with the GSI3D model
2. Information on outcrops collected during SIGMA (System for Integrated Geoscience Mapping) mapping in 2010/2011 was extracted as field observation points, Table 2 and Table 3. This information was populated into an Excel table

The two Excel tables were then merged with the ‘.bid’ and ‘.blg’ files from the Data Portal to create one ‘.bid’ file and one ‘.blg’ file for importing into GSI3D.

Table 2    Field points gathered from SIGMA mapping shown as a .bid file for import into GSI3D

Loc. No.	X	Y	Start Height	Source	10K sheet
CA 1283	293730	858720	19.86	SIGMA	NH95NW(n)
CA 1284	293730	858720	19.86	SIGMA	NH95NW(n)
CA 1285	294080	857860	26.17	SIGMA	NH95NW(n)
CA 1290	293940	857320	33.94	SIGMA	NH95NW(s)
CA 1303	294090	856690	36.59	SIGMA	NH95NW(s)
CA 1304	294030	855780	35.72	SIGMA	NH95NW(s)
CA 1305	294170	855960	32.43	SIGMA	NH95NW(s)
CA 1306	294100	855980	31.59	SIGMA	NH95NW(s)
CA 1360	290440	855030	26.61	SIGMA	NH95NW(s)
CA 1369	294950	855270	46.51	SIGMA	NH95NW(s)
CA 1370	293980	855540	39.60	SIGMA	NH95NW(s)
CA1134	286810	856000	21.61	SIGMA	NH85NE(s)
CA1142	287680	854140	15.35	SIGMA	NH85SE(n)
CA1144	287790	854280	13.45	SIGMA	NH85SE(n)
CA1149	288650	856170	9.29	SIGMA	NH85NE(s)
CA1150	288540	856400	3.23	SIGMA	NH85NE(s)
CA1151	288150	855460	14.26	SIGMA	NH85NE(s)
CA1152	288330	855580	10.01	SIGMA	NH85NE(s)
CA1153	288400	853270	25.88	SIGMA	NH85SE(n)
CA1169	289740	856980	16.00	SIGMA	NH85NE(s)
CA1170	289670	856910	15.05	SIGMA	NH85NE(s)
CA1171	289570	856730	16.78	SIGMA	NH85NE(s)
CA1173	288910	855420	11.50	SIGMA	NH85NE(s)
CA1191	289670	856350	17.45	SIGMA	NH85NE(s)
CA1281	293260	858180	23.67	SIGMA	NH95NW(n)
CA1282	293280	858280	21.22	SIGMA	NH95NW(n)
CA1287	292940	858140	13.16	SIGMA	NH95NW(n)
CA1363	291700	855550	22.44	SIGMA	NH95NW(s)
CA1364	292570	855600	37.71	SIGMA	NH95NW(s)
CA1365	293110	854690	40.69	SIGMA	NH95SW(n)
CA1366	293220	854870	37.10	SIGMA	NH95SW(n)
CA1367	293010	854860	34.47	SIGMA	NH95SW(n)
CA1368	293400	854770	39.37	SIGMA	NH95SW(n)
CA1371	293830	854660	46.82	SIGMA	NH95SW(n)
CAA_105	291955	853472	44.13	SIGMA	NH95SW(n)
CAA_109	291161	852352	58.70	SIGMA	NH95SW(n)
CAA_110	291086	852432	52.19	SIGMA	NH95SW(n)
CAA_122	294953	852654	85.32	SIGMA	NH95SW(n)
CAA19981	286940	856820	9.92	SIGMA	NH85NE(s)
CAA19982	288480	856600	20.87	SIGMA	NH85NE(s)
CAA19983	289600	855720	18.60	SIGMA	NH85NE(s)
CAA19984	288920	856410	12.17	SIGMA	NH85NE(s)
CAA19985	289790	855670	17.36	SIGMA	NH85NE(s)
CAA19986	289350	854130	35.62	SIGMA	NH85SE(n)
CAA19987	294800	858710	12.69	SIGMA	NH95NW(n)
CAA19988	294750	859040	12.99	SIGMA	NH95NW(n)
CAA19989	294630	855900	44.01	SIGMA	NH95NW(s)
CAA19990	294120	856320	30.15	SIGMA	NH95NW(s)
CAA19991	294840	855670	49.03	SIGMA	NH95NW(s)
CAA19992	290600	856260	9.69	SIGMA	NH95NW(s)
CAA19993	290330	856370	16.31	SIGMA	NH95NW(s)
CAA19994	295050	856690	30.77	SIGMA	NH95NE(s)
JDEV11	296967	855456	46.68	SIGMA	NH95NE(s)
JDEV16	299515	852944	100.99	SIGMA	NH95NE(s)
JDEV20	297323	854968	65.95	SIGMA	NH95NE(s)
JDEV21	297674	854334	77.22	SIGMA	NH95NE(s)
JDEV5	298810	855060	78.08	SIGMA	NH95NE(n)
JDEV7	295330	858260	45.78	SIGMA	NH95NE(n)
JDEV8	297990	859910	23.92	SIGMA	NH95NE(n)
MFN1	290381	852721	81.85	SIGMA	NH95SW(n)
MFN2	297500	855250	80.37	SIGMA	NH95NE(s)
MFN3	299380	850030	196.34	SIGMA	NH95SE(s)

Table 3     Field points gathered from SIGMA mapping shown as a .blg file for import into GSI3D

Loc. No.	Depth to base of unit	Lithology Code	GVS	Lithostrat
CA 1283	0.30	Soil	RMBDD	Raised marine deposits Late D.
CA 1283	0.70	Sand with tabular cobbles	RMBDD	Raised marine deposits Late D.
CA 1283	1.10	gravel	RMBDD	Raised marine deposits Late D.
CA 1283	1.50	gravel	GSG4	glaciofluvial sheet deposit
CA 1283	2.00	iron/manganeese pan	KISA	ferruginous weathered sst?
CA 1283	2.20	clay	KISA	weathered mudstone?
CA 1284	1.00	no lithology	BSA	Blown sand
CA 1284	2.20	sand with clay wisps	RMDF4	Flandrian Raised beach 4?
CA 1285	2.00	No lithology	ALV1	Alluvium
CA 1285	2.50	Diamicton	TILL	Till (?4)
CA 1290	2.10	sandy diamicton	MORD	morainic deposits
CA 1303	2.00	sandy diamicton	MORD	morainic deposits
CA 1304	0.50	sandstone	HSA	HSA ( fault slightly on wrong side!)
CA 1305	3.00	sandy gravel	GSG4	glaciofluvial sheet deposit
CA 1306	2.00	pebbly diamicton	TILL6	Till
CA 1306	2.10	siltstone	HSA	HSA
CA 1360	0.60	humic silt & clay	ALV1	Alluvium
CA 1360	1.20	sandy silty	ARDS	Ardersier Silts
CA 1369	1.50	contorted gravel & sand	GSG4	subglacial esker gravel
CA 1370	0.20	Soil	TILL6	Till
CA 1370	1.70	diamicton	TILL6	Till
CA1134	0.30	MGR	MGR	MGR
CA1134	1.00	gravel	RTFDD	raised tidal flat deposits
CA1134	1.30	sand	RTFDD	raised tidal flat deposits
CA1134	2.10	sand	ARDS	Ardersier Silts
CA1134	2.90	sand	ARDS	Ardersier Silts
CA1134	3.20	silt	ARDS	Ardersier Silts
CA1142	3.50	Sst + Mudstone	INS	INS
CA1144	2.00	Cong. + Sst	RCCN	RCCN
CA1149	1.00	Sandstone	NSTN	NSTN
CA1150	3.00	Sandstone	NSTN	NSTN
CA1151	0.30	soil	RTFDD	raised tidal flat deposits
CA1151	2.20	sand	ARDS	Ardersier Silts
CA1151	2.60	gravel	ARDS	Ardersier Silts
CA1151	3.30	sand & silt	ARDS	Ardersier Silts
CA1152	2.00	Sandstone	NSTN	NSTN
CA1153	5.00	sand & gravel	GSG4	Ice contact sand & gravel
CA1169	5.00	Sandstone	KISA	KISA
CA1170	2.50	Sandstone	KISA	KISA
CA1171	1.30	MGR	MGR	MGR
CA1171	1.40	Soil	ARDS	Ardersier Silts
CA1171	2.20	sand	ARDS	Ardersier Silts
CA1173	2.90	Sand	RTFDD	raised tidal flat deposits
CA1173	3.60	sand & clayey silt	ARDS	Ardersier Silts
CA1191	0.20	MGR	MGR	MGR
CA1191	0.50	Sand	RTFDD	raised tidal flat deposits
CA1191	0.60	silt	ARDS	Ardersier Silts
CA1191	0.90	Sand	ARDS	Ardersier Silts
CA1191	1.00	silt	ARDS	Ardersier Silts
CA1191	2.00	Sand	ARDS	Ardersier Silts
CA1191	2.80	diamicton	BALT	Balmakeith Till Member (lens)
CA1281	0.60	sand	RMBDD	Raised marine deposits Late D.
CA1281	0.80	sand, silty	RMBDD	Raised marine deposits Late D.
CA1282	2.30	sandstone & congl.	KISA	KISA
CA1287	0.80	Sand with tabular cobbles	RMBDD	Raised marine deposits Late D.
CA1287	2.40	openwork gravel	RMBDD	Raised marine deposits Late D.
CA1363	0.30	soil	ALGR	Alturlie gravels
CA1363	0.70	gravel	ALGR	Alturlie gravels
CA1363	1.50	sand gravel and silt	ALGR	Alturlie gravels
CA1364	0.50	Soil	TILL6	Till
CA1364	1.80	diamicton	TILL6	Till
CA1364	2.50	decomposed sandstone	HSA	Hillhead Sandstone (lens)
CA1365	0.20	soil	GSG4	Ice contact sand & gravel
CA1365	1.90	gravel	GSG4	Ice contact sand & gravel
CA1366	2.00	sandstone	INS	INS
CA1367	0.40	soil	GSG4	glaciofluvial sheet deposit
CA1367	0.90	gravel	GSG4	glaciofluvial sheet deposit
CA1367	1.70	diamicton	TILL6	Till
CA1368	4.50	gravel	GSG4	subglacial esker gravel
CA1368	4.80	sand	GSG4	subglacial esker sand
CA1368	5.10	silt	GSG4	subglacial esker silt
CA1368	5.50	sand	GSG4	subglacial esker sand
CA1368	7.00	gravel	GSG4	subglacial esker gravel
CA1371	0.40	soil	GSG4	Ice contact sand & gravel
CA1371	0.90	gravel	GSG4	Ice contact sand & gravel
CA1371	1.50	clayey silt	GSG4	Ice contact sand & gravel
CA1371	4.00	gravel	GSG4	Ice contact sand & gravel
CAA_105	1.20	cobble gravel	GSG4	glaciofluvial sheet deposit
CAA_109	1.00	cobble gravel	RTD1	River Terrace deposits
CAA_110	1.30	Peat	PEAT1	Peat
CAA_110	2.30	sand	ALV1	Alluvium
CAA_122	7.00	Conglomerate	MBCN	MBCN
CAA19981	5.00	Sandstone	KISA	KISA
CAA19982	0.30	MGR	MGR	MGR
CAA19982	0.80	diamicton	TILL	Till (?till2)
CAA19983	0.30	peat	LDE	lacustrine deposits
CAA19983	0.70	silt	LDE	lacustrine deposits
CAA19984	3.00	MGR	MGR	MGR
CAA19985	2.00	sand	RTFDD	raised tidal flat deposits
CAA19986	3.00	bolder & cob. Grav.	GSG4	subglacial esker gravel
CAA19987	0.20	sand	BSA	Blown sand
CAA19987	0.50	sand ferruginous	RMDF4	Flandrian Raised beach 4
CAA19988	0.50	peat	LDE	Lacustrine deposits
CAA19988	0.70	clayey silt	LDE	Lacustrine deposits
CAA19989	10.00	cobbly gravel	GSG4	subglacial esker gravel
CAA19989	10.10	sandstone	INS	INS
CAA19990	2.00	sand	ALV1	alluvium
CAA19991	2.50	cobbly gravel	GSG4	subglacial esker gravel
CAA19991	2.60	silt	GSG4	subglacial esker silt
CAA19992	0.70	clayey silt	ALV1	alluvium
CAA19992	0.80	gravel	ALV1	alluvium
CAA19993	1.50	sand	RTFDD	raised tidal flat deposits
CAA19994	1.50	sand	ALV1	alluvium
JDEV11	8.00	sandstone	NSTN	NSTN
JDEV16	10.00	sand and gravel	GSG4	Ice contact sand & gravel
JDEV20	2.00	sandstone	KISA	KISA
JDEV21	2.00	sandstone	KISA	KISA
JDEV5	6.00	sand and gravel	GSG4	Ice contact sand & gravel
JDEV7	2.00	sand and gravel	MORD	Moraine
JDEV8	1.00	diamicton	TILL4	Till
JDEV8	2.00	silt and clay	ARDS	Ardersier silts
MFN1	1.00	diamicton	TILL6	Till
MFN2	2.50	sand and gravel	GSG4	Ice contact sand & gravel
MFN3	3.00	sand and gravel	GSG4	Ice contact sand & gravel

Raster and shapefile data

• Topographic maps at 1:25 000 scale were extracted for the project area
• Two figures (22 and 28) from the Fortrose memoir (Fletcher et al., 1996) were scanned and georeferenced for use within the GSI3D project
• Two sections from the Fortrose 1:50 000 84W sheet (1997) were scanned and their raster files were used to create two sections within the project

Contour data

Onshore contours were provided from Ordnance Survey data at 5 m intervals.

Offshore bathymetry was provided as a shapefile from Arc. The files were clipped to the project area and converted into British National Grid from Latitude and Longitude.

Geological linework data

The modelled area encompasses three 1:50 000 sheet areas, Fortrose (84W), Nairn (84E) and Cromarty (94E). The Fortrose sheet was published in 1997 and linework which was available digitally from DigMap was clipped to the model area. The Nairn sheet was under revision at the time of modelling this area but 1:10 000 scale maps were available due to recent mapping and stored within the CartoGIS department. The digitally stored linework at this scale was imported into GSI3D as shapefiles. The geological linework for NH96SW part of Cromarty (94E) was also clipped and imported into GSI3D as a shapefile.

The offshore 1:250 000 Seabed Sediment map for Moray-Buchan (BGS) was clipped in Arc and converted into British National Grid from Latitude and Longitude. The offshore map was imported into GSI3D.

Offshore seismic data

In 2012 BGS undertook survey work in the Inner Moray Firth to acquire seismic and multibeam data. In an area of approximately 15 km by 5 km 33 lines were shot, Figure 3.

Figure 3 NextMap© image showing the seismic tracks for the Inner Moray Survey.

12 seismic lines (45, 46, 47, 48, 54, 59, 60, 64, 66, 67, 69 and 78) were interpreted and converted into jpeg format files, Figure 4. Before they could be imported into GSI3D the linework had to be converted to British National Grid which was undertaken in Arc. Due to the size of the files the images were cropped and resampled in order to be imported into GSI3D.

Figure 4 Seismic line 67, note also the high point of the seabed that forms the north-eastern margin of the present day channel. The angular discontinuity (orange surface) indicates that there have been several phases of deposition in the firth before erosion of the present day channel.

The depth of the cross-sections had to be converted for entry into GSI3D due to the acquisition of the offshore seismic profiles in two-way travel time. The vertical scale is measured in milliseconds and therefore has to be converted into metres.

e.g. 1500 m/s in water (so 10 ms of water on seismic line approx = 7.5 m in reality) & 1700–1800 m/s in soft sediment. N.B. seafloor depth varies across seismic lines, so average value calculated.

An example of calculating depths:-

Section 45	: av. depth from sea-level to seabed: 0.020/2 x 1500 = 15 m
	: depth from seabed to base of image: 0.200–0.020 = 0.180, 0.180/2 x 1750 =157.5 m
	: total depth (top to base of image): 15 m + 157.5 m = 172.5 m
	Figures for importing section 45 as a raster backdrop into GSI3D:
	Top left corner: W=0, Z=0          Bottom right corner: W=2366.6, Z=-172.5
	N.B. where section crosses -10m bathymetry contour, seabed pick lies at -22.5 m

Offshore multibeam data

Multibeam data were collected along seismic tracks, extending approx. 25 m either side of the seismic line, so had a network of data. Attribute table indicates there are 1 585 964 data points, a data point every 2 m over the areas scanned. The deepest value recorded was -45.96 m (between Forth George and Charonry Point) and shallowest was -4.53 m as this was the shallowest that the boat could survey.

The multibeam data gathered were not used in the construction of this model due to problems encountered in trying to import the data into GSI3D.

The file size was too large for GSI3D and even by reducing this; the data were projected in the wrong location. The data were then exported as a simple .xyz file and an .asc file at 5 m resolution (38MB). The attribute table indicated there were 305 622 data points. The files were imported into an empty GSI3D project but the Culloden-Nairn project couldn’t be loaded. The multibeam dtm was visible along the seismic sections where the it existed along the entire length of the section, but if a section cut in and out of the dtm data, the section was not constrained and shot upwards to 96 814 m or downwards to -143 117 m (on a test section). These extreme values made the dtm (as it existed) impossible to view in 3D.

The data are still stored within the project area and can be used for future offshore modelling.

Additional information

Cross-sections from other projects were brought into GSI3D as they cut through the Culloden-Nairn project area.

• 10 sections from the Great Glen-Moray Firth GSI3D Faulted Bedrock Model (Arkley, 2014)
• 5 sections from the GB-3D bedrock model
• 9 sections from the Moray Ness Regional Model (Finlayson and Arkley, 2014)

A series of surfaces to replicate the sea-level at different heights were created in GOCAD™ and clipped to the project area. These tin files represented sea level at 0 m, +7 m, +28 m and +42 m.