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ABSTRACT

Spore assemblages are described from three cored intervals in the Silurian sequence in borehole Hawiyah-151 from central Saudi Arabia. Those from the oldest cored interval are correlated with the Imperfectotriletes spp.-Laevolancis divellomedia spore Assemblage Biozone [divellomedia Interval Biozone (α Subzone)], suggesting a Rhuddanian (possibly early Aeronian) age. The older samples from the middle cored interval are correlated with the Imperfectotriletes spp.-Laevolancis divellomedia spore Assemblage Biozone [divellomedia Interval Biozone (β Subzone)], suggesting a late Aeronian-early Telychian age, but the younger samples from this interval are correlated with the chulus-nanus spore Assemblage Biozone, suggesting a late Telychian-early Homerian age. Samples from the youngest cored interval are correlated with the brevicosta-verrucatus spore Assemblage Biozone, suggesting an early (but not earliest) Homerian-?earliest Gorstian age. Palynofacies analysis indicates that the deposits of the oldest and middle cored interval accumulated in a nearshore marine environment, but those of the youngest cored interval were deposited during a nearshore marine to non-marine regressive sequence. In the middle cored interval, the abundance of chitinozoans coupled with the paucity of acritarchs is intriguing. The sequence of Silurian spore assemblages in Saudi Arabia is clearly different to that reported in Laurentia, Avalonia and probably also Baltica. In Saudi Arabia, trilete spores and ornamented hilate cryptospores appear to make their inception earlier, and envelope-enclosed cryptospores persist in relative abundance for longer.

INTRODUCTION

This paper reports on a sequence of spore assemblages from Silurian strata present in borehole Hawiyah-151 (HWYH-151) from central Saudi Arabia. The borehole is located in the central part of the Ghawar oil field, approximately 250 kilometres (km) northeast of Riyadh (Figure 1). In this borehole approximately 1,000 feet (ft) of Silurian strata, assigned to the Sarah and Qalibah formations, is present. The base of the Silurian strata apparently is not penetrated by borehole Hawiyah-151, but regionally it is believed to rest unconformably on strata assigned to the Ordovician (Qasim Formation) (see Stump et al., 1995; Wender et al., 1998). The Silurian strata is unconformably overlain by Permian deposits (Unayzah Formation) (see Stump et al., 1995; Wender et al., 1998).

Figure 1:

Palaeozoic outcrops on the Arabian Peninsula, and the Hawiyah-151 well discussed in this study.

Figure 1:

Palaeozoic outcrops on the Arabian Peninsula, and the Hawiyah-151 well discussed in this study.

All of the samples from borehole Hawiyah-151 comprise core derived from three cored intervals: core 11 (13,753.0-13,700.0 ft), core 10 (13,276.0-13,217.0 ft) and cores 9-7 (12,868.0-12,733.0 ft) (Figure 2; Appendix 1). Core 11 occurs below the Qusaiba “hot shale” in an interval considered to belong to the Sarah Formation. Core 10 occurs in the middle part of the Qusaiba member (Qalibah Formation). Cores 9-7 occur in the Sharawra Member (Qalibah Formation).

Figure 2:

Stratigraphical log for borehole Hawiyah-151.

Figure 2:

Stratigraphical log for borehole Hawiyah-151.

Samples from the cores yield moderate to well preserved palynomorph assemblages of moderate thermal maturity (spores light to dark brown in colour). In this paper we report on the spores (cryptospores and trilete spores) from the palynological preparations. Studies of acritarchs and chitinozoans from the same samples have also been undertaken (Aoudeh and Al-Hajri, 1995; Le Hérissé, this volume; Al-Hajri, personal communication, 1999).

Independent evidence for the age of the strata is limited. Chitinozoans from core 11 (13,697.0-13,701.3 ft) suggest a Late Ordovician-earliest Silurian age, and several graptolites recovered from the same core (13,697.0-13,700.7 ft) may belong to the acuminatus Graptolite Biozone indicating an earliest Rhuddanian age (Aoudeh and Al-Hajri, 1995 (well EA1=Hawiyah-151); Al-Hajri, personal communication, 1999). In a comprehensive study of the Qalibah Formation in the Ghawar area, core 10 was assigned to the Aeronian Angochitina hemeri chitinozoan biozone, suggesting a mid-late Llandovery age (Al-Hajri, personal communication, 1999). Le Hérissé (this volume) notes the presence of the chitinozoans Angochitina hemeri and Pterochitina dechai at 13,275.8 ft (core 10). There is no independent evidence for the age of the strata in cores 9-7.

SAMPLING AND TECHNIQUES

29 samples were processed of which 25 were productive (Appendix 1). Samples were prepared using standard palynological acid maceration techniques. All figured material is housed in the Department of Palaeontology of the Natural History Museum, London, UK. Individual specimens are located by providing slide details and England Finder Co-ordinates.

SYSTEMATIC PALYNOLOGY

All of the taxa encountered are described below. However, detailed descriptions are only provided for those new to science or exhibiting features of particular interest. Spore taxa are grouped under general headings relating to gross structure (and including both cryptospores and trilete spores) and therein alphabetically. A complete taxon list with full author citation is provided in Appendix 2.

Cryptospore permanent tetrads
Genus RimosotetrasBurgess, 1991 

Type species: Rimosotetras problematicaBurgess, 1991 

Rimosotetras problematicaBurgess, 1991 (Plate 1: d)

Plate 1:

All spores at magnification x1,200 except where otherwise stated. Figured material is housed in the Palaeontological Collections of the Natural History Museum, London. Well names and sample depths are followed by England Finder co-ordinates and Museum Collection Number.

  • (a) Tetrahedraletes medinensis Strother and Traverse emended Wellman and Richardson, 1993. Hawiyah-151, 12,752.5 ft, Slide 1, Q55, FM1624.

  • (b) Tetrahedraletes medinensis Strother and Traverse emended Wellman and Richardson, 1993. Hawiyah-151, 12,733.5 ft, Slide 1, Q44, FM1625.

  • (c) Tetrahedraletes medinensis Strother and Traverse emended Wellman and Richardson, 1993 (x1,500). Hawiyah-151, 13,238.0 ft, Slide 1, F21/2, FM1626.

  • (d) Rimosotetras problematicaBurgess, 1991. Hawiyah-151, 13,753.0 ft, Slide 1, K44/2, FM1627.

  • (e) Velatitetras rugosaBurgess, 1991. Hawiyah-151, 13,753.0 ft, Slide 1, V53/2, FM1628.

  • (f) Velatitetras rugosaBurgess, 1991. Hawiyah-151, 13740.0 ft., Slide 1, E51, FM1629.

  • (g) Morphon Dyadospora murusattenuataStrother and Traverse, 1979 sensu Steemans, Le Hérissé and Bozdogan et al., 1996 (x1,500). Hawiyah-151, 12,758.0 ft, Slide 1, F23/2, FM1630.

  • (h) Morphon Dyadospora murusattenuataStrother and Traverse, 1979 sensu Steemans, Le Hérissé and Bozdogan et al., 1996. Hawiyah-151, 13,225.0 ft, Slide 1, E56, FM1631.

  • (i) Morphon Dyadospora murusattenuataStrother and Traverse, 1979 sensu Steemans, Le Hérissé and Bozdogan et al., 1996. Hawiyah-151, 12,753.5 ft, Slide 1, F47/1, FM1632.

  • (j) Velatitetras laevigataBurgess, 1991 (x1,100). Hawiyah-151, 13,751.0 ft, Slide 1, L56/2, FM1633.

  • (k) Velatiteras anatoliensis Steemans, Le Hérissé and Bozdogan et al., 1996 (x1,100). Hawiyah-151, 13,217.0 ft, Slide 1, P53/2-4, FM1634.

  • (l) Pseudodyadospora laevigataJohnson, 1985. Hawiyah-151, 13,753.0 ft, Slide 1, T54/1, FM1635.

Plate 1:

All spores at magnification x1,200 except where otherwise stated. Figured material is housed in the Palaeontological Collections of the Natural History Museum, London. Well names and sample depths are followed by England Finder co-ordinates and Museum Collection Number.

  • (a) Tetrahedraletes medinensis Strother and Traverse emended Wellman and Richardson, 1993. Hawiyah-151, 12,752.5 ft, Slide 1, Q55, FM1624.

  • (b) Tetrahedraletes medinensis Strother and Traverse emended Wellman and Richardson, 1993. Hawiyah-151, 12,733.5 ft, Slide 1, Q44, FM1625.

  • (c) Tetrahedraletes medinensis Strother and Traverse emended Wellman and Richardson, 1993 (x1,500). Hawiyah-151, 13,238.0 ft, Slide 1, F21/2, FM1626.

  • (d) Rimosotetras problematicaBurgess, 1991. Hawiyah-151, 13,753.0 ft, Slide 1, K44/2, FM1627.

  • (e) Velatitetras rugosaBurgess, 1991. Hawiyah-151, 13,753.0 ft, Slide 1, V53/2, FM1628.

  • (f) Velatitetras rugosaBurgess, 1991. Hawiyah-151, 13740.0 ft., Slide 1, E51, FM1629.

  • (g) Morphon Dyadospora murusattenuataStrother and Traverse, 1979 sensu Steemans, Le Hérissé and Bozdogan et al., 1996 (x1,500). Hawiyah-151, 12,758.0 ft, Slide 1, F23/2, FM1630.

  • (h) Morphon Dyadospora murusattenuataStrother and Traverse, 1979 sensu Steemans, Le Hérissé and Bozdogan et al., 1996. Hawiyah-151, 13,225.0 ft, Slide 1, E56, FM1631.

  • (i) Morphon Dyadospora murusattenuataStrother and Traverse, 1979 sensu Steemans, Le Hérissé and Bozdogan et al., 1996. Hawiyah-151, 12,753.5 ft, Slide 1, F47/1, FM1632.

  • (j) Velatitetras laevigataBurgess, 1991 (x1,100). Hawiyah-151, 13,751.0 ft, Slide 1, L56/2, FM1633.

  • (k) Velatiteras anatoliensis Steemans, Le Hérissé and Bozdogan et al., 1996 (x1,100). Hawiyah-151, 13,217.0 ft, Slide 1, P53/2-4, FM1634.

  • (l) Pseudodyadospora laevigataJohnson, 1985. Hawiyah-151, 13,753.0 ft, Slide 1, T54/1, FM1635.

Dimensions: 29 (39) 50 μm (12 specimens measured)

Genus Tetrahedraletes Strother and Traverse emended Wellman and Richardson, 1993 

Type species: Tetrahedraletes medinensis Strother and Traverse emended Wellman and Richardson, 1993 

Tetrahedraletes medinensis Strother and Traverse emended Wellman and Richardson, 1993 (Plate 1: a, b, c)

Dimensions: 24 (35) 51 μm (59 specimens measured)

Genus VelatitetrasBurgess, 1991 

Type species: Velatitetras laevigataBurgess, 1991 

Velatitetras laevigataBurgess, 1991 (Plate 1: j)

Dimensions: 37 (45) 42 μm (4 specimens measured)

Velatitetras anatoliensisSteemans, Le Hérissé and Bozdogan, 1996 (Plate 1: k)

Dimensions: 40 and 46 μm (2 specimens measured)

Velatitetras rugosa (Strother and Traverse) Steemans, Le Hérissé and Bozdogan, 1996 (Plate 1: e, f)

Dimensions: 37 (48) 61 μm (4 specimens measured)

Cryptospore permanent dyads
Genus Dyadospora Strother and Traverse emended Burgess and Richardson, 1991 

Type species: Dyadospora murusattenuata Strother and Traverse emended Burgess and Richardson, 1991 Morphon Dyadospora murusattenuataStrother and Traverse, 1979 sensu Steemans, Le Hérissé and Bozdogan et al., 1996 (Plate 1: g, h, i)

Dimensions: murusattenuata-type 26 (37) 54 by 20 (33) 43 μm (17 specimens measured) murusdensa-type 23 (38) 52 by 23 (32) 45 μm (29 specimens measured)

Genus PseudodyadosporaJohnson, 1985 

Type species: Pseudoyadospora laevigataJohnson, 1985 

Pseudodyadospora laevigataJohnson, 1985 (Plate 1: l)

Dimensions: 28 (40) 52 by 22 (30) 37 μm (18 specimens measured)

Pseudodyadospora petasusWellman and Richardson, 1993 (Plate 2: a, b, c)

Dimensions: 28 (36) 45 μm (12 specimens measured)

Genus SegestresporaBurgess, 1991 

Type species: Segestrespora membranifera (Johnson) Burgess, 1991 

Segestrespora membranifera (Johnson) Burgess, 1991 (Plate 2: e, f)

Dimensions: 31 by 26 and 45 by 34 μm (2 specimens measured)

Segestrespora laevigataBurgess, 1991 (Plate 2: d)

Dimensions: 34 (40) 45 by 24 (32) 38 μm (6 specimens measured)

Cryptospore alete monads
Genus Rugosphaera Strother and Traverse emended Strother, 1991 

Type species: Rugosphaera tuscarorensisStrother and Traverse, 1979 

Rugosphaera sp. A (Plate 2: g, j)

Description: Alete monad circular in outline. Entire surface with an ornament consisting of convolute and anastomosing muri which form a brain-like pattern. Muri of variable width (0.5-1.0 μm) and closely spaced (<0.5 μm apart). It is unclear if the ornament is present on an enclosing envelope or an inner body (with or without a thin, laevigate enclosing envelope).

Dimensions: 24 (26) 28 μm (6 specimens measured).

Comparison and comments: Ornament differs from that in other species of Rugosphaera (R. tuscarorensisStrother and Traverse, 1979 and R. cerebraMiller and Eames, 1982). The specimen in sample 13273.6 (Plate 2j) consists of a loosely adherent group comprising at least four spores.

Plate 2:

All spores at magnification x1,200 except where otherwise stated. Figured material is housed in the Palaeontological Collections of the Natural History Museum, London. Well names and sample depths are followed by England Finder co-ordinates and Museum Collection Number.

  • (a) Pseudodyadospora petasusWellman and Richardson, 1993. Hawiyah-151, 13,225.0 ft, Slide 1, K54, FM1636.

  • (b) Pseudodyadospora petasusWellman and Richardson, 1993 (x1,500). Hawiyah-151, 13,238.0 ft, Slide 1, N27/4, FM1637.

  • (c) Pseudodyadospora petasusWellman and Richardson, 1993. Hawiyah-151, 13,273.6 ft, Slide 1, G51/4, FM1638.

  • (d) Segestrespora laevigataBurgess, 1991 (x1,100). Hawiyah-151, 13,217.0 ft, Slide 1, O44, FM1639.

  • (e) Segestrespora membranifera (Johnson) Burgess, 1991. Hawiyah-151, 13,753.0 ft, Slide 1, L59/1, FM1640.

  • (f) Segestrespora membranifera (Johnson) Burgess, 1991. Hawiyah-151, 13,753.0 ft, Slide 1, R43/1, FM1641.

  • (g) Rugosphaera sp. A. Hawiyah-151, 13,753.0 ft, Slide 1, K53/1, FM1642.

  • (h, i) Artemopyra rugaticostaDufka, 1995. Hawiyah-151, 12,752.5 ft, Slide 1, H53/1, FM1643.

  • (j) Rugosphaera sp. A. Hawiyah-151, 13,273.6 ft, Slide 1, L54/1, FM1644. Note that these specimens occur in a cluster.

  • (k) Morphon Laevolancis divellomedia-plicata sensu Steemans, Le Hérissé and Bozdogan et al., 1996. Hawiyah-151, 12,733.5 ft, Slide 1, L43/2, FM1645.

  • (l) Morphon Laevolancis divellomedia-plicata sensu Steemans, Le Hérissé and Bozdogan et al., 1996. Hawiyah-151, 12,752.5 ft, Slide 1, P49/3, FM1646.

Plate 2:

All spores at magnification x1,200 except where otherwise stated. Figured material is housed in the Palaeontological Collections of the Natural History Museum, London. Well names and sample depths are followed by England Finder co-ordinates and Museum Collection Number.

  • (a) Pseudodyadospora petasusWellman and Richardson, 1993. Hawiyah-151, 13,225.0 ft, Slide 1, K54, FM1636.

  • (b) Pseudodyadospora petasusWellman and Richardson, 1993 (x1,500). Hawiyah-151, 13,238.0 ft, Slide 1, N27/4, FM1637.

  • (c) Pseudodyadospora petasusWellman and Richardson, 1993. Hawiyah-151, 13,273.6 ft, Slide 1, G51/4, FM1638.

  • (d) Segestrespora laevigataBurgess, 1991 (x1,100). Hawiyah-151, 13,217.0 ft, Slide 1, O44, FM1639.

  • (e) Segestrespora membranifera (Johnson) Burgess, 1991. Hawiyah-151, 13,753.0 ft, Slide 1, L59/1, FM1640.

  • (f) Segestrespora membranifera (Johnson) Burgess, 1991. Hawiyah-151, 13,753.0 ft, Slide 1, R43/1, FM1641.

  • (g) Rugosphaera sp. A. Hawiyah-151, 13,753.0 ft, Slide 1, K53/1, FM1642.

  • (h, i) Artemopyra rugaticostaDufka, 1995. Hawiyah-151, 12,752.5 ft, Slide 1, H53/1, FM1643.

  • (j) Rugosphaera sp. A. Hawiyah-151, 13,273.6 ft, Slide 1, L54/1, FM1644. Note that these specimens occur in a cluster.

  • (k) Morphon Laevolancis divellomedia-plicata sensu Steemans, Le Hérissé and Bozdogan et al., 1996. Hawiyah-151, 12,733.5 ft, Slide 1, L43/2, FM1645.

  • (l) Morphon Laevolancis divellomedia-plicata sensu Steemans, Le Hérissé and Bozdogan et al., 1996. Hawiyah-151, 12,752.5 ft, Slide 1, P49/3, FM1646.

Hilate cryptospores
Genus LaevolancisBurgess and Richardson, 1991 

Type species: Laevolancis divellomedia (Chibrikova) Burgess and Richardson, 1991 

Morphon Laevolancis divellomedia-plicata sensu Steemans, Le Hérissé and Bozdogan et al., 1996 (Plate 2: k, l)

Dimensions: 19 (36) 50 μm (34 specimens measured)

Type species: Artemopyra brevicostaBurgess and Richardson, 1991 

Artemopyra rugaticostaDufka, 1995 (Plate 2: h, i)

Dimensions: 34, 37 and 63 μm (3 specimens measured)

cf. Artemopyra sp. 1 (Plate 3: a, b, c, d, e, f)

Description: Amb circular. Equatorial crassitude c. 1.0 μm wide delimits a circular hilum. Hilum ornamented with radially arranged muri. Muri straight and closely spaced, extending from the equatorial crassitude for 1/2-2/3 radius of the spore. They taper towards the proximal pole and gradually diminish in breadth and height, from a maximum of c. 0.5 μm wide by c. 0.5 μm tall. Distal surface ornamented by evenly distributed micrograna c. 0.5 μm wide, <0.5 μm tall, 0.5-1.0 μm apart.

Dimensions: 28 (35) 43 μm (14 specimens measured)

Comparisons and comments: ArtemopyraBurgess and Richardson, 1991 was emended by Richardson (1996a) to encompass only forms that are distally laevigate. Hence the use of open nomenclature when aligning this taxon with Artempoyra. In the specimens described herein the proximal radial muri appear to represent true ornament rather than artefacts of compression. We know of no previously illustrated spores with a true ornament of proximal radial muri and a distal ornament of regularly arranged micrograna. However, Burgess and Richardson (1995) note extensive variation in the population of Artemopyra radiata (Strother) Burgess and Richardson (1995) they describe. Some specimens possess proximal radial muri that extend to the proximal pole and some a distal ornament of “scattered, irregularly shaped grana c. 0.5 μm in each dimension”, although it is unclear if both characters are reported on the same spore.

Plate 3:

All spores at magnification x1,200 except where otherwise stated. Figured material is housed in the Palaeontological Collections of the Natural History Museum, London. Well names and sample depths are followed by England Finder co-ordinates and Museum Collection Number.

Plate 3:

All spores at magnification x1,200 except where otherwise stated. Figured material is housed in the Palaeontological Collections of the Natural History Museum, London. Well names and sample depths are followed by England Finder co-ordinates and Museum Collection Number.

  • (a) cf. Artemopyra sp. 1. Hawiyah-151, 12,758.0 ft, Slide 1, F24/3, FM1647.

  • (b) cf. Artemopyra sp. 1 (x1,500). Hawiyah-151, 12,758.0 ft, Slide 1, D26/3, FM1648.

  • (c) cf. Artemopyra sp. 1 (x1,500). Hawiyah-151, 12,737.0 ft, Slide 1, Q26/2, FM1649.

  • (d) cf. Artemopyra sp. 1. Hawiyah-151, 12,733.5 ft, Slide 1, T54, FM1650.

  • (e) cf. Artemopyra sp. 1. Hawiyah-151, 12,733.5 ft, Slide 1, S52/1, FM1651.

  • (f) cf. Artemopyra sp. 1. Hawiyah-151, 12,758.0 ft, Slide 1, R22/3, FM1652.

  • (g) Hispanaediscus cf. wenlockensisBurgess and Richardson, 1991. Hawiyah-151, 12,752.5 ft, Slide 1, R52/4, FM1653.

  • (h) Hispanaediscus cf. wenlockensisBurgess and Richardson, 1991. Hawiyah-151, 12,859.0 ft, Slide 1, Q57/1, FM1654.

  • (i) Hispanaediscus cf. wenlockensisBurgess and Richardson, 1991. Hawiyah-151, 12,758.0 ft, Slide 1, D24/1, FM1655.

  • (j) Hispanaediscus? sp. 1. Hawiyah-151, 13,740.0 ft, Slide 1, V43, FM1656.

  • (k) Hispanaediscus? sp. 1. Hawiyah-151, 13,740.0 ft, Slide 1, M49, FM1657.

  • (l) Hispanaediscus cf. wenlockensisBurgess and Richardson, 1991 (x1,500). Hawiyah-151, 13,745.0 ft, Slide 1, K34/4, FM1658.

Genus Hispanaediscus Cramer emended Burgess and Richardson, 1991 

Type species: Hispanaediscus verrucatus Cramer emended Burgess and Richardson, 1991 

Hispanaediscus cf. wenlockensisBurgess and Richardson, 1991 (Plate 3: g, h, i, l)

Dimensions: 26 (34) 45 μm (33 specimens measured)

Comparison and comments: The specimens described herein have identical distal ornament to H. wenlockensisBurgess and Richardson, 1991 but differ in that the proximal hilum is laevigate and lacks the proximal radial folds/muri present in the type material.

Hispanaediscus? sp. 1 (Plate 3: j, k)

Description: Amb circular. Prominent equatorial crassitude 2.0-4.5 μm wide. Proximal surface missing in both specimens examined, but there is no evidence of invagination on the crassitude indicative of a trilete mark, suggesting that the spore may be a hilate cryptospore. Distal surface ornamented with fairly densely packed verrucae of irregular size. Verrucae rounded in profile, c. 0.5 μm tall, rounded (circular-elongate) in proximal view, 0.5-2.5 μm in maximum diameter (more usually 1.0-2.0 μm), and generally <0.5 μm apart.

Dimensions: 40 and 42 μm (2 specimens measured).

Comments: This taxon is questionably assigned to the genus Hispanaediscus due to uncertainty as to the exact nature of the proximal face.

Hispanaediscus? sp. 2 (Plate 4: a, b, c, d, e, f)

Description: Amb triangular. Distinct and prominent equatorial crassitude 2.0 μm wide. Proximal surface is entirely laevigate and appears to lack a trilete mark (?hilum). Distal surface with an ornament dominated by muri and rugulae, but also with verrucae. The elements are regular in height (c. 1.0 μm) but have highly irregular shape and size in polar view. They are crowded, seldom more than 1.0 μm apart, and different shaped elements are usually randomly arranged, although in some cases rugulae are slightly coarser in the polar region. In some specimens the elements appear to have a coarse radial alignment, particularly towards the equator. Muri and rugulae meander and occasionally bifurcate. They are up to 4.5 μm in length and usually between 1.0-1.5 μm in width.

Dimensions: 37 (45) 57 μm (18 specimens measured)

Comparison and comments: This taxon is questionably assigned to the genus Hispanaediscus due to uncertainty as to the exact nature of the proximal face. It is distinct from previously described species of this genus because of its conspicuous triangular to sub-triangular shape.

Hispanaediscus sp. 3 (Plate 4: g, h, i, j, k)

Description: Amb subcircular to subtriangular. Prominent equatorial crassitude, 3.5-7.0 μm wide, delimits a subcircular to subtriangular proximal hilum. Hilum entirely laevigate. Distal surface ornamented with a crowded ornament of irregularly shaped verrucae and rugulae. Sculptural elements are similar in height (<1.0 μm) but vary dramatically in shape and size in polar view. Some are rounded but the majority contain a number of straight sides and are roughly polygonal. Elements are 2.5-6.0 μm in maximum diameter. Usually the rounded elements are smaller than the roughly polygonal elements, the former often tending to predominate in the polar region. Elements are c. 1.0 μm apart.

Plate 4:

All spores at magnification x1,200 except where otherwise stated. Figured material is housed in the Palaeontological Collections of the Natural History Museum, London. Well names and sample depths are followed by England Finder co-ordinates and Museum Collection Number.

Plate 4:

All spores at magnification x1,200 except where otherwise stated. Figured material is housed in the Palaeontological Collections of the Natural History Museum, London. Well names and sample depths are followed by England Finder co-ordinates and Museum Collection Number.

  • (a) Hispanaediscus? sp. 2. Hawiyah-151, 13,225.0 ft, Slide 1, K59, FM1659.

  • (b) Hispanaediscus? sp. 2. Hawiyah-151, 13,225.0 ft, Slide 1, E47/4, FM1660.

  • (c) Hispanaediscus? sp. 2. Hawiyah-151, 13,225.0 ft, Slide 1, N47/1, FM1661.

  • (d) Hispanaediscus? sp. 2 (x1,500). Hawiyah-151, 13,238.0 ft, Slide 1, L30/2, FM1662.

  • (e) Hispanaediscus? sp. 2. Hawiyah-151, 13,276.0 ft, Slide 1, F23/4, FM1663.

  • (f) Hispanaediscus? sp. 2. Hawiyah-151, 13,225.0 ft, Slide 1, S59/3, FM1664.

(g, h) Hispanaediscus sp. 3. Hawiyah-151, 13,225.0 ft, Slide 1, U42/4, FM1665.

  • (i) Hispanaediscus sp. 3. Hawiyah-151, 13,225.0 ft, Slide 1, E50/2, FM1666.

(j) Hispanaediscus sp. 3. Hawiyah-151, 13,225.0 ft, Slide 1, T53/4, FM1667.

(k) Hispanaediscus sp. 3. Hawiyah-151, 13,225.0 ft, Slide 1, R56/1, FM1668.

(l) Chelinohilates maculatusSteemans, Higgs and Wellman 2000 (x1,500). Hawiyah-151, 13,745.0 ft, Slide 1, M18/3, FM1669.

Dimensions: 35 (44) 57 μm (7 specimens measured)

Comparison and comments: This taxon is distinct from most previously described species of Hispanaediscus because of the nature of the ornament, which is highly irregular and includes sub-polygonal elements.

Genus ChelinohilatesRichardson, 1996a 

Type species: Chelinohilates erraticusRichardson, 1996a 

Chelinohilates maculatusSteemans, Higgs and Wellman, 2000 (Plate 4: l)

Dimensions: 32 (38) 43 μm (10 specimens measured)

Physically separated spores
Genus ImperfectotriletesSteemans, Higgs and Wellman, 2000 

Type species: Imperfectotriletes vavrdovae (Richardson) Steemans, Higgs and Wellman, 2000 

Imperfectotriletes vavrdovae (Richardson) Steemans, Higgs and Wellman, 2000 (Plate 5: c, d, e)

Dimensions: 27 (35) 43 μm (5 specimens measured)

Imperfectotriletes patinatusSteemans, Higgs and Wellman, 2000 (Plate 5: a, b)

Dimensions: 27 (38) 47 μm (13 specimens measured)

Laevolancis chibrikovaeSteemans, Higgs and Wellman, 2000 (Plate 5: f)

Dimensions: 21, 33 and 41 μm (3 specimen measured)

Plate 5:

All spores at magnification x1,200 except where otherwise stated. Figured material is housed in the Palaeontological Collections of the Natural History Museum, London. Well names and sample depths are followed by England Finder co-ordinates and Museum Collection Number.

Plate 5:

All spores at magnification x1,200 except where otherwise stated. Figured material is housed in the Palaeontological Collections of the Natural History Museum, London. Well names and sample depths are followed by England Finder co-ordinates and Museum Collection Number.

  • (a) Imperfectotriletes patinatusSteemans, Higgs and Wellman, 2000 (x1,500). Hawiyah-151, 13,238.0 ft, Slide 1, D34/1, FM1670.

  • (b) Imperfectotriletes patinatusSteemans, Higgs and Wellman, 2000. Hawiyah-151, 13,273.6 ft, Slide 1, Q48, FM1671.

  • (c) Imperfectotriletes vavrdovae (Richardson) Steemans, Higgs and Wellman, 2000. Hawiyah-151, 13,273.6 ft, Slide 1, F40/4, FM1672.

  • (d) Imperfectotriletes vavrdovae (Richardson) Steemans, Higgs and Wellman, 2000. Hawiyah-151, 12,733.5 ft, Slide 1, F53/3, FM1673. Note the remnants of the tetrad still adhering to the spore.

  • (e) Imperfectotriletes vavrdovae (Richardson) Steemans, Higgs and Wellman, 2000 (x1,500). Hawiyah-151, 12,737.0 ft, Slide 1, H32/1, FM1674.

  • (f) Laevolancis chibrikovaeSteemans, Higgs and Wellman, 2000. Hawiyah-151, 13,753.0 ft, Slide 1, O52/4, FM1675. This specimen is laterally compressed, but it is evident that the crassitude is split and the proximal face torn.

  • (g) Morphon Ambitisporites avitus-dilutus sensu Steemans, Le Hérissé and Bozdogan et al., 1996 (x1,500). Hawiyah-151, 12,737.0 ft, Slide 1, F33/4, FM1676.

  • (h) Morphon Ambitisporites avitus-dilutus sensu Steemans, Le Hérissé and Bozdogan et al., 1996. Hawiyah-151, 12,752.5 ft, Slide 1, L42, FM1677.

  • (i) Morphon Ambitisporites avitus-dilutus sensu Steemans, Le Hérissé and Bozdogan et al., 1996. Hawiyah-151, 13,225.0 ft, Slide 1, Q45/1, FM1678.

(j, k) Archaeozonotriletes chulus (Cramer) Richardson and Lister, 1969. Hawiyah-151, 12,752.5 ft, Slide 1, O52, FM1679. Note the characteristic folding at the junction between the thin proximal face and the thickened crassitude of the patina.

(l) Archaeozonotriletes chulus (Cramer) Richardson and Lister, 1969. Hawiyah-151, 12,733.5 ft, Slide 1, F56/4, FM1680. In this specimen the patina is clearly evident but the trilete mark-bearing proximal face is not easily discernible.

Trilete spores
Genus AmbitisporitesHoffmeister, 1959 Type species: Ambitisporites avitusHoffmeister, 1959 

Morphon Ambitisporites avitus-dilutus sensu Steemans, Le Hérissé and Bozdogan et al., 1996 (Plate 5: g, h, i)

Dimensions: 28 (36) 49 μm (12 specimens measured)

Genus Archaeozonotriletes (Naumova) Allen, 1965 

Type species: Archaeozonotriletes variabilis (Naumova) Allen, 1965 

Archaeozonotriletes chulus (Cramer) Richardson and Lister, 1969 (Plate 5: j, k, l)

Dimensions: 29 (37) 40 μm (5 specimens measured)

BIOSTRATIGRAPHY

The occurrence of spore taxa is outlined in Table 1. From these data three distinct sporomorph assemblages, corresponding to the three cored intervals (11, 10 and 9-7), can be identified. These are described below. Comparisons and correlation is based on recent reviews of Silurian spore biostratigraphy (e.g. Richardson and McGregor, 1986; Richardson and Edwards, 1989; Burgess and Richardson, 1995; Richardson, 1996b) and reports describing spore assemblages from and in close vicinity to the Middle East (Steemans et al., 1996; Steemans et al., this volume).

Table 1

Stratigraphic occurrence of spore taxa

TAXACORE SAMPLE11 2811 2711 2611 2511 2411 2311 2210 2010 1910 1810 1710 1610 159-7 149-7 139-7 119-7 109-7 99-7 5a9-7 59-7 49-7 39-7 29-7 1
Rimosotetras problematica xxx---xxxxx-x--xxx---xx-
Tetrahedraletes medinensis xxxxxxxxxxxxxx-xxxxxx-xx
Velatitetras laevigata -xx----x-x--x-----------
Velatitetras anatoliensis ------------x-----------
Velatitetras rugosa x--x--?-----------x--x--
Dyadospora murusattenuata xxxxxxxxxx-xxx-xxxxxxxxx
Pseudodyadospora laevigata xx-xx-xxxx--------------
Pseudodyadospora petasus --x----xxxxxx------xx---
Segestrespora membranifera x-----------------------
Segestrespora laevigata -x--x-------x-----------
Rugosphaera sp. A xx------x---------------
Laevolancis divellomedia-plicata -xx-xx-----x-x-xxxxxx-xx
Artemopyra rugaticosta -------------------xxxxx
cf. Artemopyra sp. 1 ------------------xx-xxx
Hispanaediscus cf. wenlockensis --------------xxx--xx-xx
Hispanaediscus? sp. 1 --xx--------------------
Hispanaediscus? sp. 2 -------x-xxxx-----------
Hispanaediscus sp. 3 ----------xx------------
Chelinohilates maculatus --x---------------------
Imperfectotriletes vavrdovae --------xxxxx---------xx
Imperfectotriletes patinatus x-x-----xxxxx--------x--
Laevolancis chibrikovae xx----------------------
Ambitisporites avitus-dilutus ----xx---x-x--xx----xxxx
Archaeozonotriletes chulus ------------x-----x-xx-x
TAXACORE SAMPLE11 2811 2711 2611 2511 2411 2311 2210 2010 1910 1810 1710 1610 159-7 149-7 139-7 119-7 109-7 99-7 5a9-7 59-7 49-7 39-7 29-7 1
Rimosotetras problematica xxx---xxxxx-x--xxx---xx-
Tetrahedraletes medinensis xxxxxxxxxxxxxx-xxxxxx-xx
Velatitetras laevigata -xx----x-x--x-----------
Velatitetras anatoliensis ------------x-----------
Velatitetras rugosa x--x--?-----------x--x--
Dyadospora murusattenuata xxxxxxxxxx-xxx-xxxxxxxxx
Pseudodyadospora laevigata xx-xx-xxxx--------------
Pseudodyadospora petasus --x----xxxxxx------xx---
Segestrespora membranifera x-----------------------
Segestrespora laevigata -x--x-------x-----------
Rugosphaera sp. A xx------x---------------
Laevolancis divellomedia-plicata -xx-xx-----x-x-xxxxxx-xx
Artemopyra rugaticosta -------------------xxxxx
cf. Artemopyra sp. 1 ------------------xx-xxx
Hispanaediscus cf. wenlockensis --------------xxx--xx-xx
Hispanaediscus? sp. 1 --xx--------------------
Hispanaediscus? sp. 2 -------x-xxxx-----------
Hispanaediscus sp. 3 ----------xx------------
Chelinohilates maculatus --x---------------------
Imperfectotriletes vavrdovae --------xxxxx---------xx
Imperfectotriletes patinatus x-x-----xxxxx--------x--
Laevolancis chibrikovae xx----------------------
Ambitisporites avitus-dilutus ----xx---x-x--xx----xxxx
Archaeozonotriletes chulus ------------x-----x-xx-x

Core 11

Assemblages from this core are dominated by cryptospores, with true trilete spores only appearing towards the top of the core where they are represented by rare specimens of the laevigate crassitate spore Ambitisporites sp. It is notable that envelope-enclosed cryptospores are relatively common in all of the preparations from this core, and include tetrads, dyads and monads enclosed in either laevigate or ornamented (rugulate-murornate) envelopes. An important occurrence is that of hilate cryptospores, including laevigate and ornamented (Hispanaediscus? sp.1 and Chelinohilates maculatus) forms. Monads physically separated from polyad cryptospores are relatively common, including those removed from dyads (L. chibrikovae) and tetrads (I. patinatus).

The assemblages from core 11 can be correlated with the Imperfectotriletes spp.-Laevolancis divellomedia spore Assemblage Biozone [divellomedia Interval Biozone (α Subzone)] (Steemans et al., this volume). Correlation with this spore zone is based on general characteristics of the assemblage and the occurrence of certain taxa. Salient features are: (1) L. divellomedia is present; (2) trilete spores (Ambitisporites sp.) are present but rare; (3) envelope-enclosed cryptospores are common; and (4) monads physically separated from polyad cryptospores are common. Spore assemblages belonging to the same subzone are reported from the Nuayyim-2 (NYYM-2) borehole in Saudi Arabia (Steemans et al., this volume), and both the Hawiyah-151 and Nuayyim-2 assemblages are very similar with many taxa in common, including C. maculatus. The occurrence of ornamented hilate cryptospores at this level is intriguing. Such spores seemingly appear later (based on spore occurrences in independently age constrained strata) in well known spore sequences from elsewhere, for example, from North Africa, Spain, southern Britain and North America.

Correlation with the Imperfectotriletes spp.-Laevolancis divellomedia spore Assemblage Biozone [divellomedia Interval Biozone (α Subzone)] suggests a Rhuddanian (possibly early Aeronian) age.

Core 10

Assemblages from this core are dominated by cryptospores. True trilete spores are present but are uncommon, and are represented by laevigate crassitate forms (Ambitisporites sp.) and, in the youngest sample from the core, laevigate patinate forms (Archaeozonotriletes chulus). Envelope-enclosed cryptospores are present throughout the core, but are never as abundant as in the preceding core 11. Hilate cryptospores include laevigate and ornamented (Hispanaediscus? sp. 2 and Hispanaediscus sp. 3) forms. Monads physically separated from polyad cryptospores are relatively common, but only include those derived from tetrads (I. vavrdovae and I. patinatus). A noteworthy feature of the assemblages from core 10 is the relative abundance of Pseudodyadospora petasus.

The assemblages from core 10 can for the main part be correlated with the Imperfectotriletes spp.-Laevolancis divellomedia spore Assemblage Biozone [divellomedia Interval Biozone (β Subzone)] (Steemans et al., this volume), although the youngest assemblage from this core (13,217 ft) apparently belongs with the overlying chulus-nanus spore Assemblage Biozone (Richardson and McGregor, 1986; Steemans et al., this volume). Correlation with the former is based on: (1) trilete spores (Ambitisporites sp.) are reasonably common; and (2) envelope-enclosed cryptospores are present but uncommon. Correlation with the latter is based on the occurrence of the patinate trilete spore Archaeozonotrilete chulus in the youngest sample from this core. However, it should be noted that this spore is rare in this sample, and possibly occurs in older samples but has not been reported due to its scarcity. Again, the occurrence of ornamented hilate cryptospores throughout this core is intriguing, because such spores seemingly appear later in well known spore sequences from elsewhere. It is also noteworthy that Hispanaediscus? sp. 2 is not reported from older Hawiyah-151 core 11 spore assemblages (correlated with the divellomedia Interval Biozone (α Subzone)), but is reported (albeit in small numbers) from the nearby Nuayyim-2 borehole in assemblages also assigned to the divellomedia Interval Biozone (α Subzone).

Correlation with the Imperfectotriletes spp.-Laevolancis divellomedia spore Assemblage Biozone [divellomedia Interval Biozone (β Subzone)] suggests a late Aeronian-early Telychian age, and with the chulus-nanus spore Assemblage Biozone a late Telychian-early Homerian age.

Cores 9-7

Assemblages from these cores are dominated by cryptospores, although true trilete spores are relatively common and are represented by laevigate crassitate (Ambitisporites sp.), and laevigate patinate (Archaeozonotriletes chulus) forms. Envelope-enclosed cryptospores are rare, and only represented by Velatitetras rugosa. Hilate cryptospores include laevigate forms and abundant ornamented forms, including those with proximal radial ribs (Artemopyra rugaticosta and cf. Artemopyra sp. 1) and distal murornate sculpture (Hispanaediscus cf. wenlockensis). Monads physically separated from polyad cryptospores are present, but again only include those derived from tetrads.

The assemblages from cores 9-7 can be correlated with the Artemopyra brevicosta-Hispanaediscus verrucatus spore Assemblage Biozone (Richardson and McGregor, 1986; Burgess and Richardson, 1995). Correlation with this zone is based on: (1) the occurrence of abundant ornamented hilate cryptospores, including those with proximal radial ribs and distal murornate ornament; and (2) the occurrence of abundant laevigate trilete spores including Ambitisporites sp. and Archaeozonotriletes chulus.

Reports of Silurian spore assemblages from the Middle East are rare, and thus comparisons are confined to well known spore sequences from palaeogeographically distant regions (North Africa, Spain, southern Britain and North America). Here sculptured hilate cryptospores (proximal radial ribs and distal murornate sculpture) first appear at the base of the brevicosta-verrucatus spore Assemblage Biozone. Succeeding biozones are characterised by an increase in abundance and diversity of ornamented hilate cryptospores and trilete spores. It must be emphasised that, in this case, correlation is with spore zonation schemes established in distant regions and may not be entirely reliable. For example, it has already been demonstrated (based on spore occurrences in independently age constrained strata) that trilete spores and ornamented hilate cryptospores occur earlier in Turkey and Saudi Arabia than in North Africa, Avalonia and Laurentia (Steemans et al., 1996; this volume). Furthermore, ornamented trilete spores are present in the brevicosta-verrucatus spore assemblages from southern Britain (Burgess and Richardson, 1995), but appear to be absent from the cores 9-7 assemblages from Saudi Arabia.

Correlation with the brevicosta-verrucatus spore Assemblage Biozone suggests an early (but not earliest) Homerian-?earliest Gorstian age.

PALYNOFACIES

Palynological preparations from the three cored intervals have very different characteristics and can be considered separately.

Core 11

Palynological preparations from core 11 are dominated by spores (cryptospores and rare trilete spores). Phytodebris, in the form of tubular structures, is also usually present but is not particularly abundant. Acritarchs and chitinozoans are almost invariably present, and are usually relatively common. The presence of typical marine forms (acritarchs and chitinozoans) indicates a marine setting, but the abundance of land-derived material (spores and phytodebris) suggests close proximity to shore.

Core 10

Palynological preparations from core 10 are dominated by spores (cryptospores and trilete spores). Phytodebris, in the form of a diverse array of tubular structures, is abundant in most preparations. Chitinozoans are almost invariably present, and are particularly common in certain samples (e.g. 13,273.6 ft). Intriguingly, however, acritarchs are either entirely absent or extremely rare. The presence of chitinozoans indicates a marine setting, but then the absence/paucity of acritarchs requires explanation. The abundance of land-derived material (spores and phytodebris), and the presence of possible fresh-water algal cysts (Le Hérissé, this volume), suggests close proximity to shore.

Cores 9-7

Palynological preparations from cores 9-7 are again dominated by spores (cryptospores and trilete spores) and phytodebris (diverse tubular structures). Acritarchs and chitinozoans occur in the older assemblages (although only very sporadically) but become increasingly scarce, and occasionally entirely absent, as the sequence youngs. It seems likely that there is some marine influence in the older strata, but this declines up sequence. It is possible that some of the youngest assemblages are entirely non-marine and were deposited in a terrestrial environment.

CONCLUSIONS

Studies of Silurian spores are still in their infancy, with relatively few spore assemblages (either isolated or in sequences) described in detail, and palaeogeographical coverage limited. The sequence of spore assemblages described herein represents a rare report of Silurian spores from Saudi Arabia. The new material is therefore invaluable in our endeavour to fully understand the temporal and spatial distribution of Silurian spores. However, caution must be exercised in accepting proposed correlation and age dating of the Saudi Arabian spore assemblages that for the most part lack independent age constraints (i.e. particularly the assemblage from cores 9-7).

Recent work has demonstrated differences between coeval palynofloras during Silurian times. For example, trilete spores and ornamented hilate cryptospores appear to make their inception earlier in Turkey and Saudi Arabia than in North Africa, Spain, southern Britain and North America (Steemans et al., 1996; this volume), and Late Silurian palynofloras from North Africa, Spain and southern Britain exhibit significant differences (Steemans, 1999; Richardson, personal communication, 1999). Consequently, in the absence of independent age control, and particularly when age determination is based on comparisons with spore zonation schemes established in palaeogeographically distant regions, correlation and age determination must be considered tentative. Nonetheless, this work is of considerable importance in our attempt to unravel the biostratigraphical distribution of Silurian spores in Saudi Arabia. It represents the first step in establishing a regional (Saudi Arabian) spore biostratigraphy for the Silurian, thus making future integration of regional and global schemes possible, particularly as more independent biostratigraphical information becomes available.

Appendix 1

Details of samples

No.Sample Depth (ft)CorePreservation
112,733.59-7Excellent
212,737.39-7Poor
312,740.19-7Average
412,752.59-7Average-Good
512,758.09-7Excellent
5a12,758.29-7Excellent
612,779.09-7Barren
712,798.09-7Barren
812,813.09-7Barren
912,835.09-7Poor
1012,839.09-7Poor
1112,840.09-7Poor
1212,847.09-7Barren
1312,859.09-7Average
1412,868.09-7Poor
1513,217.010Excellent
1613,225.010Excellent
1713,238.010Good
1813,270.910Excellent
1913,273.610Good
2013,276.010Good
2113,700.811Barren
2213,729.011Poor
2313,731.011Poor
2413,737.011Average-Poor
2513,740.011Poor
2613,745.511Average
2713,751.011Average
2813,753.011Average
No.Sample Depth (ft)CorePreservation
112,733.59-7Excellent
212,737.39-7Poor
312,740.19-7Average
412,752.59-7Average-Good
512,758.09-7Excellent
5a12,758.29-7Excellent
612,779.09-7Barren
712,798.09-7Barren
812,813.09-7Barren
912,835.09-7Poor
1012,839.09-7Poor
1112,840.09-7Poor
1212,847.09-7Barren
1312,859.09-7Average
1412,868.09-7Poor
1513,217.010Excellent
1613,225.010Excellent
1713,238.010Good
1813,270.910Excellent
1913,273.610Good
2013,276.010Good
2113,700.811Barren
2213,729.011Poor
2313,731.011Poor
2413,737.011Average-Poor
2513,740.011Poor
2613,745.511Average
2713,751.011Average
2813,753.011Average

Appendix 2

Author citation of taxa listed in text

Ambitisporites avitusHoffmeister, 1959

Ambitisporites dilutus (Hoffmeister) Richardson and Lister, 1969

Archaeozonotriletes chulus (Cramer) Richardson and Lister, 1969

Artemopyra rugaticostaDufka, 1995 cf. Artemopyra sp. 1

Chelinohilates maculatusSteemans, Higgs and Wellman, 2000

Dyadospora murusattenuata Strother and Traverse emended Burgess and Richardson, 1991

Dyadospora murusdensa Strother and Traverse emended Burgess and Richardson, 1991

Hispanaediscus cf. wenlockensis Cramer emended Burgess and Richardson, 1991

Hispanaediscus? sp. 1

Hispanaediscus? sp. 2

Hispanaediscus sp. 3

Imperfectotriletes patinatusSteemans, Higgs and Wellman, 2000

Imperfectotriletes vavrdovae (Richardson) Steemans, Higgs and Wellman, 2000

Laevolancis chibrikovaeSteemans, Higgs and Wellman, 2000

Laevolancis divellomedia (Chibrikova) Burgess and Richardson, 1991

Laevolancis plicataBurgess and Richardson, 1991

Pseudodyadospora laevigataJohnson, 1985

Pseudodyadospora petasusWellman and Richardson, 1993

Rimosotetras problematicaBurgess, 1991

Rugosphaera sp. A

Segestrespora laevigataBurgess, 1991

Segestrespora membranifera (Johnson) Burgess, 1991

Tetrahedraletes medinensis Strother and Traverse emended Wellman and Richardson, 1993

Velatitetras laevigataBurgess, 1991

Velatitetras rugosa (Strother and Traverse) Steemans, Le Hérissé and Bozdogan, 1996

ACKNOWLEDGEMENT

The authors acknowledge with gratitude the Saudi Arabian Ministry of Petroleum and Mineral Resources and the Saudi Arabian Oil Company for permission to publish this study. Shir Akbari (SOES, SOC, Southampton) is thanked for preparing the samples and operating the elemental analyser.

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A.M.
Al-Moqbel
1998
.
Paleozoic (Pre-Khuff) Hydrocarbon Geology of the Ghawar Area
,
Eastern Saudi Arabia. GeoArabia
 , v.
3
, no.
2
, p.
273
-
302
.

ABOUT THE AUTHORS

Charles H. Wellman, Ken T. Higgs and Philippe Steemans (see page 115)

Figures & Tables

Figure 1:

Palaeozoic outcrops on the Arabian Peninsula, and the Hawiyah-151 well discussed in this study.

Figure 1:

Palaeozoic outcrops on the Arabian Peninsula, and the Hawiyah-151 well discussed in this study.

Figure 2:

Stratigraphical log for borehole Hawiyah-151.

Figure 2:

Stratigraphical log for borehole Hawiyah-151.

Table 1

Stratigraphic occurrence of spore taxa

TAXACORE SAMPLE11 2811 2711 2611 2511 2411 2311 2210 2010 1910 1810 1710 1610 159-7 149-7 139-7 119-7 109-7 99-7 5a9-7 59-7 49-7 39-7 29-7 1
Rimosotetras problematica xxx---xxxxx-x--xxx---xx-
Tetrahedraletes medinensis xxxxxxxxxxxxxx-xxxxxx-xx
Velatitetras laevigata -xx----x-x--x-----------
Velatitetras anatoliensis ------------x-----------
Velatitetras rugosa x--x--?-----------x--x--
Dyadospora murusattenuata xxxxxxxxxx-xxx-xxxxxxxxx
Pseudodyadospora laevigata xx-xx-xxxx--------------
Pseudodyadospora petasus --x----xxxxxx------xx---
Segestrespora membranifera x-----------------------
Segestrespora laevigata -x--x-------x-----------
Rugosphaera sp. A xx------x---------------
Laevolancis divellomedia-plicata -xx-xx-----x-x-xxxxxx-xx
Artemopyra rugaticosta -------------------xxxxx
cf. Artemopyra sp. 1 ------------------xx-xxx
Hispanaediscus cf. wenlockensis --------------xxx--xx-xx
Hispanaediscus? sp. 1 --xx--------------------
Hispanaediscus? sp. 2 -------x-xxxx-----------
Hispanaediscus sp. 3 ----------xx------------
Chelinohilates maculatus --x---------------------
Imperfectotriletes vavrdovae --------xxxxx---------xx
Imperfectotriletes patinatus x-x-----xxxxx--------x--
Laevolancis chibrikovae xx----------------------
Ambitisporites avitus-dilutus ----xx---x-x--xx----xxxx
Archaeozonotriletes chulus ------------x-----x-xx-x
TAXACORE SAMPLE11 2811 2711 2611 2511 2411 2311 2210 2010 1910 1810 1710 1610 159-7 149-7 139-7 119-7 109-7 99-7 5a9-7 59-7 49-7 39-7 29-7 1
Rimosotetras problematica xxx---xxxxx-x--xxx---xx-
Tetrahedraletes medinensis xxxxxxxxxxxxxx-xxxxxx-xx
Velatitetras laevigata -xx----x-x--x-----------
Velatitetras anatoliensis ------------x-----------
Velatitetras rugosa x--x--?-----------x--x--
Dyadospora murusattenuata xxxxxxxxxx-xxx-xxxxxxxxx
Pseudodyadospora laevigata xx-xx-xxxx--------------
Pseudodyadospora petasus --x----xxxxxx------xx---
Segestrespora membranifera x-----------------------
Segestrespora laevigata -x--x-------x-----------
Rugosphaera sp. A xx------x---------------
Laevolancis divellomedia-plicata -xx-xx-----x-x-xxxxxx-xx
Artemopyra rugaticosta -------------------xxxxx
cf. Artemopyra sp. 1 ------------------xx-xxx
Hispanaediscus cf. wenlockensis --------------xxx--xx-xx
Hispanaediscus? sp. 1 --xx--------------------
Hispanaediscus? sp. 2 -------x-xxxx-----------
Hispanaediscus sp. 3 ----------xx------------
Chelinohilates maculatus --x---------------------
Imperfectotriletes vavrdovae --------xxxxx---------xx
Imperfectotriletes patinatus x-x-----xxxxx--------x--
Laevolancis chibrikovae xx----------------------
Ambitisporites avitus-dilutus ----xx---x-x--xx----xxxx
Archaeozonotriletes chulus ------------x-----x-xx-x
No.Sample Depth (ft)CorePreservation
112,733.59-7Excellent
212,737.39-7Poor
312,740.19-7Average
412,752.59-7Average-Good
512,758.09-7Excellent
5a12,758.29-7Excellent
612,779.09-7Barren
712,798.09-7Barren
812,813.09-7Barren
912,835.09-7Poor
1012,839.09-7Poor
1112,840.09-7Poor
1212,847.09-7Barren
1312,859.09-7Average
1412,868.09-7Poor
1513,217.010Excellent
1613,225.010Excellent
1713,238.010Good
1813,270.910Excellent
1913,273.610Good
2013,276.010Good
2113,700.811Barren
2213,729.011Poor
2313,731.011Poor
2413,737.011Average-Poor
2513,740.011Poor
2613,745.511Average
2713,751.011Average
2813,753.011Average
No.Sample Depth (ft)CorePreservation
112,733.59-7Excellent
212,737.39-7Poor
312,740.19-7Average
412,752.59-7Average-Good
512,758.09-7Excellent
5a12,758.29-7Excellent
612,779.09-7Barren
712,798.09-7Barren
812,813.09-7Barren
912,835.09-7Poor
1012,839.09-7Poor
1112,840.09-7Poor
1212,847.09-7Barren
1312,859.09-7Average
1412,868.09-7Poor
1513,217.010Excellent
1613,225.010Excellent
1713,238.010Good
1813,270.910Excellent
1913,273.610Good
2013,276.010Good
2113,700.811Barren
2213,729.011Poor
2313,731.011Poor
2413,737.011Average-Poor
2513,740.011Poor
2613,745.511Average
2713,751.011Average
2813,753.011Average

Contents

GeoRef

References

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