In Search of the Kingdom's Ediacarans

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IN SEARCH OF THE KINGDOM'S EDIACARANS: THE FIRST GENUINE METAZOANS (MACROSCOPIC BODY AND TRACE FOSSILS) FROM THE NEOPROTEROZOIC JIBALAH GROUP (VENDIAN/EDIACARAN) ON THE ARABIAN SHI...

ARTICLE · JANUARY 2013

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Patricia Vickers Rich Peter Robert. Johnson

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Tom Rich Museum Victoria

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Ulf Linnemann Senckenberg Naturhistorische Sammlunge…

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Available from: Tom Rich Retrieved on: 11 February 2016 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield IN SEARCH OF THE KINGDOM’S EDIACARANS: THE FIRST GENUINE METAZOANS (MACROSCOPIC BODY AND TRACE FOSSILS) FROM THE NEOPROTEROZOIC JIBALAH GROUP (VENDIAN/EDIACARAN) ON THE ARABIAN SHIELD

PATRICIA VICKERS-RICH, ANDREI IVANTSOV, FAYEK H. KATTAN, PETER R. JOHNSON, ASHRAF AL QUBSANI, WADEE KASHGHARI, MAXIM LEONOV, THOMAS RICH, ULF LINNEMANN, MANDY HOFMANN, PETER TRUSLER, JEFF SMITH, ABDULLAH YAZEDI, BEN RICH, SAAD M. AL GARNI, ABDULLA SHAMARI, ADEEB AL BARAKATI, AND MOHAMMAD H. AL KAFF

Cenozoic basalt draped Neoproterozoic sequence with Cambrian Saq Sandstone overlying the Neoproterozoic Jibalah Group as a Backdrop, Northwestern Arabian Shield

www.sgs.org.sa

TECHNICAL REPORT SGS-TR-2013-5

1434 H 2013 G Saudi Geological Survey Technical Report - SGS-TR-2013-5 i In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield

A Technical Report prepared by the Saudi Geological Survey, Jeddah, Kingdom of Saudi Arabia

The work on which this report is based was performed in support of Saudi Geological Survey Subproject Subproject - The Eastern Arabian Shield: Window into Supercontinental Assembly at the Dawn of Animal Life. It has been edited and reviewed by staff of the Saudi Geological Survey. Product names used in this report are for descriptive purposes and in no way imply endorsement by SGS. This report is a product of the Saudi Geological Survey; if the information herein is used in any form, either quoted or paraphrased, this report should be properly cited using the full serial number, the author’s name(s), and the year of publication. The correct citation for this report is: Vickers-Rich, P., Ivantsov. A., Ka an, F.H., Johnson, P.R., Al Qubsani, A., Kashghari, W., Leonov, M., Rich, T., Linnemann, U., Hofmann, M., Trusler, P., Smith, J., Yazidi, A., Rich, B., Al Garni, S.M., Shamari, A., Al Baraka , A., and Al Ka , M.H., 2012, In search of the Kingdom’s Ediacarans: The ﬁ rst genuine Metazoans (macroscopic body and trace fossils) from the Neoproterozoic Jibalah Group (Vendian/Ediacaran) on the Arabian Shield: Saudi Geological Survey Technical Report SGS-TR-2013-5, 21 p., 19 ﬁ gs., 1 table. In common with most reports produced by the Saudi Geological Survey, this report is available for sale to the public in hard copy format or on CD in PDF format. Please contact the SGS Publications Center at the address in Jeddah below for more information.

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13° 13° Study Areas This map should not be used as a reference for international borders. 12° 12° 36° 37° 38° 39° 40° 41° 42° 43° 44° 45° 46° 47° 48° 49° 50° 51° 52° 53° 54° 55° 56° 57° 58° 59° Index map of the Arabian Peninsula

For more information about the Saudi Geological Survey visit our website www.sgs.org.sa or write to or visit our headquarters in Jeddah or our ofﬁ ce in Riyadh. Saudi Geological Survey Saudi Geological Survey-Riyadh Office Post Office Box 54141, Jeddah 21514 Post Office Box 6955, Riyadh 11452 Tel. (966-2) 619-5000 Tel. (966-1) 476-5000 ii Saudi Geological Survey Technical Report - SGS-TR-2013-5 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield TABLE OF CONTENTS

Page ENGLISH ABSTRACT ...... 1 ARABIC ABSTRACT ...... 2 INTRODUCTION AND BACKGROUND ...... 3 PRECAMBRIAN SEQUENCES IN THE ARABIAN SHIELD AND THE METAZOAN RECORD IN THE KINGDOM ...... 3 JIBALAH GROUP ...... 6 GEOCHRONOLOGY ...... 7 DHAIQA BASIN, DHAIQA FORMATION ...... 8 MACROSCOPIC FOSSILS FROM THE DHAIQA FORMATION ...... 11 MATERIAL ...... 14 Background and comparisons...... 14 Macroscopic metazoan body fossils from the Dhaiqa formation ...... 15 JIF’N BASIN, JIF’N FORMATION ...... 17 Horodyskia-like macrofossils from the Jif’n formation ...... 17 Geologic setting ...... 18 Afﬁ nities of Horodyskia ...... 18 DISCUSSION, CONCLUSIONS AND FUTURE INVESTIGATIONS ...... 18 ACKNOWLEDGMENTS ...... 19 REFERENCES ...... 19 EPILOGUE ...... 21

FIGURES Figure 1. Neoproterozoic outcrops of interest in the search for Ediacaran fossils...... 4 Figure 2. The late Mesoproterozoic-middle Neoproterozoic Rodinia supercontinent...... 5 Figure 3. Tectonic setting of the Arabian Plate...... 5 Figure 4. Jibalah group outcrops in the northern part of the Arabian Shield...... 6 Figure 5. Stratigraphic columns for selected exposures of the Jibalah group...... 7 Figure 6. Plot of U-Pd data and age of 560±4 Ma from the youngest zircons in the Dhaiqa formation...... 8 Figure 7. View of the Dhaiqa formation...... 8 Figure 8. Section of the Al Wajh Quadrangle Sheet 26B (Davies, 1985) prospected for Ediacarans...... 9 Figure 9. Stratigraphic section of the middle part of the Dhaiqa formation...... 10 Figure 10. Member c of Section 8 of the Dhaiqa formation from which the dated ash sample was collected...... 10 Figure 11. Surface which produced structure shown in ﬁ gures 15-16...... 11 Figure 12. View of the Dhaiqa formation...... 11 Figure 13. Volcanic ash overlying the red fossiliferous sandstone in the Dhaiqa formation...... 12 Figure 14. Concordia age plot for tuff layer overlying Ediacarans in ﬁ gure 16...... 12 Figure 15. Harlaniella sp. from the Terminal Proterozoic of Saudi Arabia (1) and Late Vendian of Russia (2)...... 14 Figure 16. Possible Charnia-like metazoan Dhaiqa formation...... 16 Figure 17. Ediacaran-like structure (“Cyclomedusa-Aspidella” holdfast construction), Dhaiqa formation...... 16 Figure 18. Possible trace fossils in Jibalah Group in the Jabel Al Hamra area...... 17 Figure 19. Possible Horodyskia from the Jif’n basin...... 17

Saudi Geological Survey Technical Report - SGS-TR-2013-5 iii In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield CONTENTS (Cont’d.)

Page

TABLE Table 1. U-Th-Pb isotopic data on the tuff layer plotted in ﬁ gure 14...... 13

iv Saudi Geological Survey Technical Report - SGS-TR-2013-5 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield IN SEARCH OF THE KINGDOM’S EDIACARANS: THE FIRST GENUINE METAZOANS (MACROSCOPIC BODY AND TRACE FOSSILS) FROM THE NEOPROTEROZOIC JIBALAH GROUP (VENDIAN/EDIACARAN) ON THE ARABIAN SHIELD

PATRICIA VICKERS-RICH1, ANDREI IVANTSOV2, FAYEK H. KATTAN3, PETER R. JOHNSON4, ASHRAF AL QUBSANI3, WADEE KASHGHARI3, MAXIM LEONOV2, THOMAS RICH5, ULF LINNEMANN6, MANDY HOFMANN6, PETER TRUSLER1, JEFF SMITH1, ABDULLAH YAZEDI3, BEN RICH1, SAAD M. AL GARNI3, ABDULLA SHAMARI3, ADEEB AL BARAKATI3, AND MOHAMMAD H. AL KAFF3

ABSTRACT

Ediacarans make up the oldest known truly diverse metazoan assemblages and are known globally. However, few sites have produced abundant fossils, and until recently such fossils were unknown in Arabia. Generally restricted to the late Neoproterozoic, the best known assemblages occur in China, Newfoundland, the White Sea in northern Russia, the Flinders Ranges of South Australia and southern Namibia in Africa. Less diverse assemblages are known from Siberia, Ukraine, UK, and a few sites in Asia, and North and South America. Ediacarans occur primarily in shallow marine derived sands and clays with the exception of

Newfoundland forms that may have inhabited light free depths in a volcanically active terrane. They are known in rock sequences dating from 630 Ma to 540 Ma, the Ediacaran or Vendian period, the youngest division of Precambrian time. New discoveries in Saudi Arabia over the past 5 years have brought to light the presence of Ediacarans, both traces and body fossils, suggesting that further investigation most likely will yield a much more diverse assemblage, and one that may well have inhabited less saline environs that is typical for other Ediacarans. Fossils similar to Harlaniella, known elsewhere from the late Precambrian and Cambrian, and megascopic frond-like forms have been discovered in a single layer that is overtopped by a volcanic ash, dated at 569 ± 3 Ma, thus giving both good preservation and precision dating of the Dhaiqa formation in the Dhaiqa basin and its enclosed Ediacarans. In addition, the discovery of Horodyskia-like fossils in the Jif’n basin is a ﬁ rst occurrence for Saudi Arabia. They have a similar Neoproterozoic age to forms found in China, both of which are signiﬁ cantly younger than the more than 1 billion year old forms found in North America and Australia.

1School of Geosciences, Monash University, Melbourne (Clayton), Victoria 3800 Australia 2Paleontological Ins tute, Russian Academy of Sciences, Profsoyuznaya ul. 123, Moscow, Russia 3Saudi Geological Survey, P.O. Box 54141, Jeddah, 21514 Saudi Arabia 46016 SW Haines Street, Portland, Oregon 97219, USA 5Museum Victoria, Box 666, Melbourne, Victoria 3001 Australia 6Senckenberg Naturhistorische Sammlungen Dresden, Museum für Mineralogie und Geologie, Königsbrücker Landstraße 159, Dresden, D-01109, Germany

Saudi Geological Survey Technical Report - SGS-TR-2013-5 1 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield

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2 Saudi Geological Survey Technical Report - SGS-TR-2013-5 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield INTRODUCTION AND BACKGROUND The minimum age for the Dhaiqa sediments has been dated at 560 ± 4 million years (Vickers-Rich and others, 2010), Ediacarans, organisms which make up the oldest known well within the late Neoproterozoic, and thus Vendian truly diverse metazoan assemblages, are known globally, (Ediacaran) in age. but few sites have produced abundant fossils, and until recently such organisms were unknown in Arabia (Vickers- Rich, and others, 2010). Generally restricted to the late Neoproterozoic, the most biodiverse assemblages occur, PRECAMBRIAN SEQUENCES ON THE oldest to youngest, in China, Newfoundland, the White Sea ARABIAN SHIELD AND THE METAZOAN northern Russia, the Flinders Ranges of South Australia and RECORD IN THE KINGDOM southern Namibia in Africa (Fedonkin and others (2007), The best exposed Neoproterozoic sequences in the Vickers-Rich and Komarower (2007). Smaller and less Kingdom of Saudi Arabia which seemed likely to yield diverse assemblages are known from Siberia, Ukraine, UK, Vendian (Ediacaran) fossils crop out in the western part and from a few sites in Asia, and in North and South America. of the Arabian Shield, and thus this area was targeted. The They occur in shallow marine derived sands and clays building of the Arabian Shield began with the assembly of with the exception of Newfoundland forms that may have the supercontinent Rodinia from 1000-750 Ma, followed inhabited light-free depths in a volcanically active terrane by its fragmenting beginning around 750 million years ago, (Narbonne and others, 2009). These organisms are found and continued until the assembly of the cratonic blocks of in sedimentary rocks chiefl y dating from about 630 Ma to eastern and western Gondwana. Break-up of Rodinia (fi g. 540 Ma that stratigraphically are assigned to the Ediacaran 2) led to the formation of an oceanic basin referred to as or Vendian period, the youngest division of Precambrian the Mozambique Ocean, located between rifted parts of time. Ediacaran and Vendian are interchangeable terms, Rodinia and the separate continental masses of Congo-Sao although Ediacaran will be the term most familiar to readers in Saudi Arabia. In this report, Vendian is the preferred Francisco and Kalahari (Meert and Liebermann, 2008). stratigraphic term; Ediacaran is used mainly to refer to the On the basis of paleomagnetic-pole studies of cratonic fossil contents of the rocks. sequences of the supercontinent Gondwana and isotope Neoproterozoic sediments, some quite unaltered, are dating, the Arabian Shield and its counterpart in NE Africa, abundant on the Arabian Shield in western Saudi Arabia. the Nubian Shield, are part of the East African accretionary Prior to 2010 there were a few reports suggesting that orogen and is known to extend along the eastern margin of Ediacaran fossils might be present in some of these sequences Africa and parts of India and Madagascar. (Johnson, 2006; Miller and others, 2008). Following on The orogen is a great collision zone, which prior to these reports, a program was organized to prospect many of Gondwanan breakup stretched from Antarctica to Jordan the fault bound sequences. along the present-day eastern margin of Africa, and through Areas targeted from 2008 through 2012 lay on the Madagascar, parts of India and the Arabian Peninsula. The northwestern part of the Arabian Shield inland from Duba history during this time is clearly complex and appears to and west of Al Ula as well as north of Hanakiyah and have ended with a period of extension and collision. further to the east to the region around Afi f and Dawadimi. Apart from small areas of Archean to Paleoproterozoic These are all areas where the Jibalah Group is exposed in a rocks, the rocks of the Arabian-Nubian Shield are number of fault controlled basins. Field work was carried Neoproterozoic. They accumulated in the Mozambique out from 2008 to 2012 A.D. (1429-1433 A.H.) as a joint Ocean, and initial deposits were mainly sedimentary such project of the Saudi Geological Survey, Monash University as epiclastic-carbonate sequences laid down along the edge (Australia) and the Paleontological Institute of the Russian of the East Sahara Metacraton. Later rocks (850-550 Ma) Academy of Sciences, and as part of the UNESCO include juvenile oceanic arcs, vast amounts of granitoids, International Correlation Projects IGCP493 and IGCP587 and middle Cryogenian-Ediacaran sedimentary basins. (www.geosci.monash.edu.au/precsite, Vickers-Rich and Beginning about 850 Ma, the rifted cratons of Rodinia others, 2010). Resulting from this work, the fi rst certain rearranged, the Mozambique Ocean closed through sea- ichnofossils were discovered – rod-shaped traces with fl oor subduction and the continental fragments of eastern oblique transverse marks which are described in this paper and western Gondwana periodically converged to form the as Harlaniella sp. Along with this, there are specimens that new supercontinent of Gondwana. Such convergence swept show resemblance to holdfasts (Aspidella, etc.) and frond- together deformed oceanic terrains of the Mozambique like forms with attached holdfasts, resembling Charnia Ocean, thus reworking the margins of older cratonic and related forms (see Fedonkin and others, 2007). Other blocks. Unprecedented tectonic, biological, biochemical specimens were recovered with a striking similarity to the and climatic changes were the outcome of this rifting and enigmatic macro-form, Horodyskia, previously known from reassembly of supercontinents. Oceanic basins formed and several locales globally and with a broad time range, from were destroyed, and glaciations, both global and local, took 1.2 billion to about 635 million years. These new fossils place. Animal and plant life proliferated, some of the fi rst occur within the Jibalah Group in two areas on the the metazoans (animals), the Ediacarans (Vendians), appeared, Arabian Shield, one from the Dhaiqa formation to near Al followed by an explosion of biodiversity in the fi rst 20-30 Ula in the northwest (fi g. 1, area 3) and the other from million years of the Cambrian, beginning around 542 Ma the Jif’n formation northeast of Hanakiyah (fi g. 1, area 8). ago (Gradstein and others, 2004).

Saudi Geological Survey Technical Report - SGS-TR-2013-5 3 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield

Figure 1. Neoproterozoic outcrops of interest in the search for Ediacaran fossils on the Arabian Shield (modiﬁ ed from a map in the Saudi Geological Survey Archives). Areas 3 and 8 were produc ve.

The rocks of the Arabian Shield are exposed in the and rock assemblages characteristic of present-day plate western part of the Arabian Plate, which since about 30-25 margins. Diverse tectonic settings have been recognized: Ma has been drifting away from Africa and colliding with ocean-plateaus, spreading ridges, intraoceanic island arcs, Eurasia (ﬁ g. 3). In the 1960’s Precambrian rocks of the Shield continental-margin island arcs, as well as passive margins. were interpreted in terms of Wilson-cycle plate tectonics, Since the 1970’s , the shield rocks have been analyzed in terms drawing analogies between the structural and chemical of tectonostratigraphic terranes. In this model, ophiolite/ characteristics of rock assemblages found on the shield serpentinite fault zones signify old sutures and represent

4 Saudi Geological Survey Technical Report - SGS-TR-2013-5 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield

Figure 2. One reconstruc on of the late Mesoproterozoic-middle Neoproterozoic Rodinia supercon nent prior to Neoproterozoic break-up (a er Meert and Liebermann, 2008) showing the loca on of the Mozambique Ocean between Rodinia and separate cratonic blocks not connected with Rodinia at this me.

Thrust fault NAF North Anatolian fault Strike-slip fault EAF East Anatolian fault Transform fault DST Dead Sea transform Plate movement Arabian-Nubian shield Plate boundary Figure 3. Tectonic se ng of the Arabian plate showing its boundaries, rates of dri , and kinema c interac ons with adjoining plates. Red arrows show the senses of trajectories of the Arabian and adjacent plates, and rates of movement (a er Johnson and Ka an, 2012).

Saudi Geological Survey Technical Report - SGS-TR-2013-5 5 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield remnants of collapsed ocean basins sandwiched between group consists of sedimentary rocks and volcanic fl ows that convergent crustal blocks. A large part of the granitoid were originally mapped as part of the Shammar group, rocks of the shield represent late- to posttectonic intrusions but were later separated and recognized as a distinct unit into the terranes, and late Cryogenian-Vendian sedimentary above an unconformity (Delfour, 1970). Together with and volcanic rocks represent post-amalgamation basins the recently recognized Kurayshah Group (Nicholson and deposited unconformably on newly amalgamated terranes others, 2008), which overlies the Jibalah group in the Al (Johnson and others, 2011). ‘Ula area, they are the youngest depositional units in the Arabian Shield, and the youngest rocks of any type in the JIBALAH GROUP shield apart from minor intrusive sills. The Jibalah group (Delfour, 1970) (alternative spellings: The group has a thickness of more than 3,300 m, J’balah, Jubaylah) crops out in small, isolated basins adjacent varying somewhat from basin to basin. The base of the to Najd faults (fi g. 4). The basins tend to be synclinoria. group in most basins is a polymict conglomerate (fi g. 5), Although the group is virtually unmetamorphosed, tilting passing up into sandstone or mafi c volcanic rocks, or cherty and folding are apparent in all the basins, and deformation limestone. Sandstone with subordinate to minor siltstone, in some is quite pronounced, with the development of conglomerate, and limestone dominates the upper part disharmonic, en-echelon, and S- and Z-shaped asymmetric of the succession in most basins. Some of the thickest folds (Kusky and Matsah, 2003). Northwest-trending limestone occurs in Jibalah basins in the northwestern shield faults occur along the margins of, as well as within, many (Miller and others, 2008). Limestone commonly contains basins. Many faults have sinistral offsets and are typical undulose bedding, representing algal mat deposition. In sinistral Najd faults, but dextral slip is also apparent. The places, the group includes diamictite, a distinctive type

Figure 4. Map showing Jibalah group outcrops in the northern part of the Arabian Shield, illustra ng their close spa al rela onship to the NW West trending regional faults.

6 Saudi Geological Survey Technical Report - SGS-TR-2013-5 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield

Figure 5. Schema c stra graphic columns for selected exposures of the Jibalah group, based on descrip ons reported by earlier workers. of conglomerate of possible glaciogenic origin, in which that blanketed the trace and body fossils, similar to the cobble- to boulder-sized clasts are supported by a sandy preservational situation in the Neoproterozoic of the Avalon matrix. Some geologists argue that the group was deposited Peninsula of Newfoundland (Narbonne and others, 2009) in fault-controlled basins; others that the group was is currently under study, and if successful will give a precise formerly more extensive and is preserved in down-faulted date for this assemblage (Linnemann and others, under blocks (Johnson, 2003). preparation). Zircons from Sample Day-1 were analyzed for U, GEOCHRONOLOGY Th, and Pb isotopes by LA-ICP-MS techniques at the Museum für Mineralogie und Geologie (Senckenberg The Jibalah and Kurayshah groups are older than the Naturhistorische Sammlungen, Dresden), using a Thermo- regional Lower Cambrian basal unconformity of ~540-520 Scientifi c Element 2 XR sector fi eld ICP-MS coupled to Ma associated with the phase of terminal Neoproterozoic- a New Wave UP-193 Excimer Laser System. A teardrop- early Cambrian uplift and peneplanation that marked the shaped, low volume laser cell developed by Ben Jähne fi nal development of the shield, and younger than the shield (Dresden, Germany) was used to enable sequential sampling rocks on which they rest. Kusky and Matsah (2003) report of heterogeneous grains (e.g., growth zones) during time a U-Pb concordia age of 577±6 Ma for a felsite dike that resolved data acquisition. Each analysis consisted of intrudes the group in the north-central part of the shield approximately 15 s background acquisition followed by and Nettle (2009) describes LA-ICP-MS ages for zircons 35 s data acquisition, using a laser spot-size of 25 and 35 from Jibalah group ash beds in the east of the shield as young µm, respectively. A common-Pb correction based on the as 573±12 Ma, 568±11 Ma, and 585±10 Ma comparable interference- and background-corrected 204Pb signal and with the age of Hamammat group in Eastern Desert, Egypt. a model Pb composition (Stacey and Kramers, 1975) was Kennedy and others (2011) infer a maximum deposition carried out if necessary. The necessity of such a correction age of about 570 Ma for the Daiqa formation on the basis was judged on whether the corrected 207Pb/206Pb lay outside of a zircon grain from an ash bed that has a core SHRIMP the internal errors of the measured ratios. age of 599±5 Ma and a rim age of 570±5 Ma. Nicholson and others (2008) report robust SHRIMP zircon ages of The results of LA-ICP-MS U-Pb zircon dating are 588–600 Ma from tuff beds within the Jibalah group near summarized in Vickers-Rich and others (2010) and the Al ‘Ula. youngest dates are shown on the concordia diagrams in fi gure 6. In this study we referred dates to those of the In order to more precisely constrain the age of geologic time scale of Gradstein and others (2004). metazoans described here, ash samples were collected for dating, and in the case of our work in the Dhaiqa section A concordia age of 560±4 Ma was calculated from the to the west of Al ‘Ula in Unit C of our stratigraphic section youngest zircon population (17 grains) (fi g. 6). The ash 8, zircons were extracted and dated successfully (Sample bed represents a volcanogenic deposit within the Dhaiqa Day-1) (26°39’37”N/37°25’56”E). A further sample succession and is used to indicate that the maximum age

Saudi Geological Survey Technical Report - SGS-TR-2013-5 7 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield of sedimentation of the Dhaiqa stratum c in our section 8, DHAIQA BASIN, DHAIQA FORMATION in the region to the west of Al ‘Ula is younger than 560±4 Of all the sections examined in 2008-2012, the most Ma. All older zircon populations seem to be related to promising, and repeatedly revisited, was in the Dhaiqa basin older Pan-African orogenic events. Just below this ash layer, to the west of Al Ula (fi g. 7), near the confl uence of Wadi al a possible Pteridinium-like impression was collected during Jizl and Wadi Dayqah (fi g. 8). The Dhaiqa formation crops our exploration of this area. Other likely metazoan body out (jd) in the lower right hand corner lying in a complex fossils and traces were found upsection from this dated tuff. of volcanics and coarse clastics, such as the Salih formation (ds) and Misyal formation (dm). The area exhibits a variety of lithologies, structurally affected and they are not highly altered. It was from this section that Miller and others (2008) reported possible Ediacarans and trace fossils. New material was recovered through much of this sequence and the sequence is worthy of an even more detailed search in the future. The section is outstanding because of the variety of sediments and the frequency of datable tuffs so that a precise dating of the sequence is both possible and underway. Section 8 illustrated in fi gure 9 produced the ash samples (fi g. 10) which confi rm the age of the Dhaiqa sequence as 560 ± 4 million years, well within the time range of the Vendians/Ediacarans and confi rm earlier reports (Miller and others, 2008). It is signifi cantly above this layer that the trace fossils reported herein were collected, so a maximum age for them is this determination, certainly within the Late Figure 6. Concordia plot and concordia age of 560±4 Ma from Neoproterozoic, and below the Siq formation, which has an the youngest zircon popula on of sample Day 1. Errors are on the 2 level. Early Cambrian age.

Figure 7. Dhaiqa forma on with view looking west between ridges 2 (le ) and 3 (right) with vehicles in centre. Northeastern- most sec on of Al Wajh Quadrangle, Sheet 26B Kingdom of Saudi Arabia (Saudi Geological Survey).

8 Saudi Geological Survey Technical Report - SGS-TR-2013-5 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield

Figure 8. Sec on of the Al Wajh Quadrangle Sheet 26B (Davies, 1985) prospected for Ediacarans.

Saudi Geological Survey Technical Report - SGS-TR-2013-5 9 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield

Units defined in Section 8

Member a. Interbedded stromatolitic limestones and calcareous shales, 4.6 m thick Member b. Greenish arkosic sandstone with mudstone intertongues. Ash layer up to several millimeters in thickness. 1.2 m thick Member c. Green mudstone with two layers of reddish-grey ash at the top. 0.3 m thick. Ash sample with date of 560±4 my (Linnemann/Hofmann, this paper) Member d. Interbedded stromatolitic limestone and calcareous shales. 2.4 m thick Member e. Glauconitic coarse-grained sandstone with gravel sized clasts, overlain by conglomerate with pebbles and breccia of both sedimentary and intrusive origin. Possible diamictite. 0.8 m thick Member f. Massive grayish-yellow limestone without clearly defined lamination. 0.2 m thick Member g. Interbedded stromatolitic limestones and calcareous shale. 3.3 m thick

Figure 9. Stra graphic sec on 8 on the southern side of Ridge 3 of the Middle Dhaiqa forma on (26°39’37” N/37°25’56” E), and descrip on of members (Miller and others, 2008).

Figure 10. Member c of Sec on 8 from which ash sample with date of 560 +/- 4 and dated by Linnemann and Hofmann was collected (Vickers-Rich and others, 2010).

10 Saudi Geological Survey Technical Report - SGS-TR-2013-5 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield MACROSCOPIC FOSSILS FROM THE DHAIQA FORMATION During the fi eld work of a team from IGCP 493 in 2008- 2009, a number of rod-shaped fossils with oblique transverse marks were discovered, exhibiting remarkable similarity to the fossil taxon Harlaniella sp. This material was recovered from the Middle Dhaiqa formation meters above the level in section 8 (fi g. 9). The productive surface is shown in fi gure 11, and crops out along the top of a 3 km long ridge with strong dip to the south, south-east (fi g. 12). The productive layer hosting the fossils, preserved in positive relief, occurs just below thin layers (1-2 cm thickness) of a tuff (fi g. 13), which blankets the fossiliferous surface. The ash from Arabia has been dated at 569 ± 3 Ma, based on the youngest zircons in the sample (fi g. 14 and table 1, with one grain core producing a date of 621 ± 14 Ma, a typical Pan-African date.

Figure 11. Surface which produced the structure in ﬁ gures 15- 16.

Figure 12. View back to the east with the ﬁ eld vehicles in posi on as in ﬁ gure 5, from the site on top of ridge 2/3, B in Vickers-Rich and others, 2010, where trace and body fossils were recovered .

Saudi Geological Survey Technical Report - SGS-TR-2013-5 11 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield

Figure 13. Volcanic ash overlying the red fossiliferous sandstone which preserves possible body fossil remains in the Dhaiqa forma on to the SW of Al ‘Ula.

Figure 14. Concordia age plot for tu layer (ﬁ g. 13) that overlies Ediacaran fossils from the Al Ula region of the NW Arabian Shield illustrated in ﬁ gure 16, with a determina on of 569 ± 3 Ma.

12 Saudi Geological Survey Technical Report - SGS-TR-2013-5 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield

98 96 98 98 99 99 99 99 100 100 100 conc % conc

85 90 52 65 60 74 84 2 131 112 180 128 (Ma) U calculated using using calculated U

235 Pb Pb 572 589 576 574 574 571 581 575 579 584 626 Pb/ 207 206 207

21 27 23 12 27 18 22 21 24 39 30 2 (Ma) n 14, which14, n corea from is one of

U Pb 562 570 569 572 573 571 574 573 574 577 622 235 207

5 8 8 16 18 29 16 20 15 15 14 2 (Ma)

U Pb 559 566 567 571 572 572 572 572 573 576 621 238 206

0.61 0.15 0.63 0.52 0.87 0.73 0.72 0.59 0.28 0.32 0.36 rho 3 Ma. The only is grai exception

g Stacey and Kramers (1975) model Pb composition. Pb model g (1975) Kramers Stacey and % 2 3.9 6.0 4.1 2.4 3.0 2.8 3.4 3.8 5.2 8.3 5.9

ducibility of GJ-1 (2SD). c Pb Pb 206 207 0.05915 0.05959 0.05924 0.05919 0.05920 0.05910 0.05938 0.05922 0.05933 0.05946 0.06062

% 2 4.9 6.1 5.3 2.8 6.1 4.1 4.9 4.7 5.4 8.7 6.4

c U Pb 235 errors (2SE) and the repro the and (2SE) errors 207 0.73850 0.75374 0.75120 0.75638 0.75740 0.75547 0.76003 0.75767 0.76076 0.76565 0.84523 concordia age of this ash is 569is ash concordia ofage this

% 2 3.0 0.9 3.3 1.5 5.3 3.0 3.6 2.8 1.5 2.8 2.3

c U Pb 238 206 0.09056 0.09174 0.09196 0.09269 0.09279 0.09271 0.09283 0.09280 0.09300 0.09339 0.10113

ratic addition of within-run c ation and common Pb (if detectable, see analytical method) usin method) analytical see detectable, (if Pb common and ation

Pb Pb 250 235 8442 1040 4747 9039 7413 6830 1060 3189 204 206 12792 10427 Pb/ 207

b layer plotted in figure 14. The U 14, a typical Pan typical a age. African 14, U/err Th 0.34 0.34 0.35 0.50 0.21 0.24 0.29 0.30 0.20 0.31 0.71 238 Pb/ b Pb signal in counts per second per counts in signal Pb 206 7 8 9 9 7 9 7 5 6 12 16 207 Pb (ppm) (ppm) b U 77 80 94 93 78 98 68 57 69 128 125 (ppm) (ppm)

a Pb Pb × 1/137.88). Errors are propagated by quad by propagated are Errors 1/137.88). × Pb (cps) 4997 4759 4562 5367 7584 4958 6203 4609 3641 3193 206 207 15871 U/ 238 zircon. Itan shows age of 621 U-Th-Pb isotopic U-Th-Pb data on tuff the Pb/(

206 a12 a18 a21 a11 a15 a16 a20 a31 a17 a32 a14 Pb/ Number 207 within-run background-corrected mean mean background-corrected within-run corrected for background, mass bias, laser induced U-Pb fraction induced laser bias, mass background, for corrected U and Pb content and Th/U ratio were calculated relative to GJ-1 and are accurate to approximately 10%. approximately to GJ-1 are accurate to relative and were calculated ratio Th/U and content Pb Uand err defined as correlation error the is Rho Table 1. a b c d

Saudi Geological Survey Technical Report - SGS-TR-2013-5 13 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield MATERIAL the newly described genus Paleopascichnus, at that time also placed within the Pascichnia. Fedonkin (1981) included On the western slope of this ridge, in the scree, one of us Harlaniella in another trace fossil group, where repeated (PVR) found a small slab (7x11 cm) of a greenish-grey, cross- forward and sideways movement were recorded. Narbonne laminated sandstone with a thickness of approximately 26 and others (1987) also noted that this taxon was a trace, but mm that hosted a group of linear imprints of certain biotic Kiryanov (1968) had in the past suggested that Harlaniella origin on the side considered to be the sole, evidenced by represented a chain of coprolites. Still others (Crimes, the nature of sedimentary lamination (fi g. 15). The traces 1992) thought the trace could be a spiral burrow that had are narrow and with very low mold profi les. The longest infi lled with sediment, but Jensen (2003) and Jensen and trace is approximately 90 mm. Preservation is of moderate others (2006) did not agree, noting that it would have been quality because of the low relief. In only some areas is the geometrically impossible to preserve such spiral traces (with detail of the oblique striations preserved (fi g. 15). Despite the transition from oblique to linear) and suggested that this, such a feature allows identifi cation of these traces as Harlaniella was a body fossil. representing the Late Proterozoic – Early Cambrian genus Harlaniella. This taxon includes several species of tubular Jensen (2003) studied the Kotlin-aged Harlaniella from fossils. the St Petersburg region, a form which differs somewhat from the Podolian material. He noted the presence on the BACKGROUND AND COMPARISONS same surfaces with Harlaniella of other fossils that appeared Harlaniella was fi rst described as H. podolica by B.S. to be fl attened tubes with longitudinal deformation folds. Sokolov in 1972 based on material from the Komarovo It may be that both of these fossil types are different styles beds which crop out along the right bank of the Dniester of preservation of the same organism. We have noted River in the Podolia region of the Ukraine. These fossils that material from the late Vendian succession cropping were fi rst interpreted as traces made by annelid works. Later out in the White Sea area of northern Russia has forms Palij and others (1979) suggested that Harlaniella should of Harlaniella sp. that do not bear a striated surface. On be placed in the trace fossil group Pascichnia, i.e. grazing some specimens of Harlaniella there are abrupt transitions traces. He further noted the similarity of this taxon with from areas with relatively smooth surfaces bearing only

Figure 15. Harlaniella sp. from the Terminal Proterozoic of Saudi Arabia (1) and Late Vendian of Russia (2). A, areas of surface with longitudinal stria on; b, areas with primary transverse stria on. Scale 1 cm. 1, SA08/810, Al Balata?, Jibalah Group, Dhaiqa forma on; 2, PIN3993/499, southeastern White Sea region, Kotlin Regional Stage, Erga forma on (Palij and others, 1979; Fedonkin and others, 2007).

14 Saudi Geological Survey Technical Report - SGS-TR-2013-5 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield longitudinal deformation marks (fi g. 15 -2, a) to other areas regional stage of the upper Vendian. This same form was with dense, oblique, inclined striations (fi g. 15-2, b). The recovered from borehole sediments of the southern Baltic White Sea specimens do not form bundles that are common Shield (of Kotlin age; Palij and others, 1979; Jensen, for the type species of H. podolica (Fedonkin and others, 2003). Harlaniella is also known in the lower part of the 2007). The specimens of Harlaniella from Saudi Arabia Chapel Island formation in southewestern Newfoundland are, in fact, strikingly similar to those from the White Sea (Narbonne and others, 1987), and very similar to the White and the St Petersburg region. Sea material. Narbonne established an ichnozone for this form that lay below the (= ) , Typically H. podolica is preserved as positive imprints Trichophycus Treptichnus pedum on the sole or bottom surfaces of thin sandstone beds, itself an international standard denoting the Precambrian- which are interbedded with clay. This interpretation of Cambrian boundary. these fossils is as sand casts of a trace originally preserved on The Ediacaran member of the Rawnsley Quartzite a muddy substrate. The thickness of the fossil material may cropping out in the Flinders Ranges of South Australia has be much greater than the thickness of the sand layer and the produced similar forms (Jenkins, 1995). And, so it seems fossil appears as a rod, which could have been covered by that H. podolica and H sp. are markers for the terminal part mud from above and below, allowing another interpretation of the late Neoproterozoic, the Upper Vendian/Ediacaran or of these remains as a record of body fossils. in the transition to the Cambrian. The Tommotian history of is enigmatic. comes from the Similar to the Podolian Harlaniella, H. sp. from the Harlaniella H. confusa White Sea, the St Petersburg region and Saudi Arabia Wood Canyon Formation deposits of probable Atdabanian- possesses some features characteristic of body fossils. Botomian age. These sediments contain trilobites (Signor, Occasional relief changes along the length of the fossil from 1994). In the upper part of the Lower Cambrian and positive to negative. This may refl ect preservation of tubes younger, Harlaniella is absent. So, at present, it appears that were fi lled or unfi lled with sediment along the length of that H. podolica and H. sp. seem to be good markers of the tube. Clearly the material in this case did not survive to the Upper Redkino-Kotlin Regional Stages of the Upper present. Originally, if this were indeed a tube, the clockwise Vendian. But the overall stratigraphic distribution of the striations of the original might have been deformed and so genusHarlaniella may well be late Vendian/Ediacaran to masked by secondary deformation. Early Cambrian in age. It should be noted that some researchers have suggested Harlaniella confusa from the Early Cambrian of California is the form most similar to the tubular model that Harlaniella has affi nities with Palaeopasichnus and that (Signor, 1994). This species is characterized by abrupt both could well be body fossils (Jensen, 2003; Shen and changes of orientation of the striations. Striations vary others, 2007). Although the debate continues, both views from clockwise to transverse to counterclockwise twisting. suggest that Harlaniella was of metazoan affi nity, be it body Thus, Signor suggested these fossils were ichnofossils and fossil or trace. that the variation of the striations refl ected changes in the MACROSCOPIC METAZOA BODY FOSSILS FROM movement of the form producing the trace. THE DHAIQA FORMATION Longitudinal folds and furrows as well as the oblique On a fi nal note, the slab from the Dhaiqa formation contains striation do not necessarily preserve easily, and so without a fossil that does differ from H. sp. It consists of a narrow this combination of characters it is diffi cult to narrow the band, preserved in positive relief that narrows at one end identifi cation to Harlaniella. Thus, this taxon may be much and is curved (fi g. 16). Along the longitudinal axis of this more widespread than noted. The record of this form spans “band” there are a few narrow, crest-like fl anges. Perhaps the Late Vendian (Ediacaran) to Early Cambrian on several this is a cast of a faceted conical tube, but it is unclear continents. H. podolica is found only in Podolia in several exactly what the preservation style is. It may well, in fact, formations within the Kanilovka series (Kotlin region stage represent one of the frond-like taxa with a basal holdfast, of the Vendian System; Palij and others, 1979). Güreev very similar to Charnia, but further specimens need to be (1988) noted that the boundary between the Kanilovka and gathered to establish true identity. Baltic series (Vendian-Cambrian) in these regions can be Vickers-Rich and others (2010), also reported determined on the basis of the presence of in the H. podolica Beltanelloides/Nemiana, as well as a holdfast structure Vendian and the fi rst occurrence of at the base of Planolites Cyclomedusa/Aspidella-like( fi g. 17 ) and possible traces (fi g. the Cambrian. However, we note here that Harlaniella has 18 ) from the Dhaiqa and other Jibalah Group sequences, in a wider distribution, ranging up into the Cambrian. particular a possible Eoandromeda octobranchiata material Harlaniella sp. are present in the Verkhovka, Zimnie from the Muraykhah formation (considered to be the Gory and Erga formations of the southeastern White Sea youngest unit in the Jibalah by Hadley, 1987) to the south region of northern Russia. The fi rst two formations are of Al Úla in the Al Bada region. All of this material is in the Redkino regional stage, and the latter in the Cotlin fi gured in that report and needs further investigation.

Saudi Geological Survey Technical Report - SGS-TR-2013-5 15 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield

Figure 16 . Specimens found directly below a volcanic ash, that may well represent Charnia-like metazoans, Dhaiqa forma on, to the southwest of Al Ula.

Figure 17 . Ediacaran-like structure (“Cyclomedusa-Aspidella” holdfast construc on) derived from sediments in sec on 8 Dhaiqa forma on, preserved as a posi ve relief (scale bar = 1 cm).

16 Saudi Geological Survey Technical Report - SGS-TR-2013-5 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield

Figure 18 . Possible trace fossils in Jibalah Group in the Jabel Al Hamra area to the southeast of Al ‘Ula (width of slab = 1 m).

JIF’N BASIN, JIF’N FORMATION South China occurrences indicate Horodyskia-like fossils with an age of ~551 million years (Shen and others, 2007). A new discovery of some interest was a rare specimen recovered from the mainly dark mudstones of the Jif’n It would seem, therefore, that this taxon has a large formation of the Jibalah group to the NE of Hanakiyah, time range, with which the occurrences of the Arabian in a region that had been more highly altered than the specimens in the Jibalah group rocks in Saudi Arabia are nearly unaltered sediments of the Dhaiqa formation.. In entirely consistent with the younger Chinese forms with the 2011 one of us (WK) found a single specimen of a form age of ~551 million years. strikingly similar to the “string of beads” like multicelled HORODYSKIA-LIKE MACROFOSSILS FROM THE and colonial Horodyskia, ﬁ rst reported from sediments in JIF’N FORMATION Montana and western Australia as much as between 1.4 and 1.2 billion years old (Fedonkin and Yochelson, 2002; Grey Besides the discovery specimen of 2011, further material and Williams, 1990). Conversely, more recently discovered was collected in 2012. The best preserved is the discovery

Figure 19 . Horodyskia–like structures from the Jif’n basin, NE of Hanakaiyah, scale in cm. (SGS Specimen Number SGS2011-1).

Saudi Geological Survey Technical Report - SGS-TR-2013-5 17 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield specimen with several strings of Horodyskia fossils (SGS AFFINITIES OF HORODYSKIA specimen number SGS 2011-1), which is 10.6 cm long, 4.5 There has been much discussion concerning the cm in width, about 1 cm in depth (see fi g. 19). It was taxonomic placement of Horodyskia, some researchers found as fl oat in an area that had been deeply burrowed suggesting it represents a colonial metazoan (Fedonkin by some sort of vertebrate, thus was from a layer buried and Yochelson, 2002), while others suggest an algal affi nity under cover, though much of the remainder of this outcrop (Grey and Williams, 1990). Whatever the case, Horodyskia is well exposed. Fossils occur as imprints in a black, is certainly a multicellular, tissue grade organism and its calcareous mudstone. Because the specimen was collected occurrence in late Neoproterozoic of Saudi Arabia is one of as fl oat, sole and top of bedding could not be defi nitely or the latest occurrence of this taxon. determined. However, in 2012 further exploration of this outcrop area did indeed locate the productive beds to the east of the original discovery and the fossils occur on the DISCUSSION, CONCLUSIONS AND top of the bed. A broad area of the outcrop in this region FUTURE INVESTIGATIONS of the Jif’n formation is characterized by ripple marked and microbial matt surface textures on both the top and sole of Four expeditions, joint programs between the Saudi the beds. Geological Survey, two institutions in Australia (the School of Geosciences of Monash University and Museum Victoria, The Horodyskia-like structures occur in strings that Melbourne) and the Paleontological Institute of the Russian curve across the surface, each module about 0.5 to 1 mm Academy of Sciences (Moscow) during 2008 - 2012 led in diameter. Strings vary in number of modules from 3 to to nearly four months of prospecting the Neoproterozoic 8 or more. Each of the modules in the strings has a thick sequences on the Arabian Shield, in search of Ediacaran rim around the circumference. No other detail concerning biota. Some intriguing structures were discovered, some of original living tissue can be discerned, as is certainly the the most diagnostic reported here. What was discovered, case in other occurrences of Horodyskia in North America however, points to a highly organic rich nature of many and Australia (Grey and Williams, 1990; Fedonkin and of the sediments of the Jibalah Group, with widespread Yochelson, 2002). In the case of the Arabian occurrence, microbially controlled bedding surfaces, and thus far a the modules are closely associated and not separated by minimum evidence for forms such as Beltanelloides and intermediate spaces. The spacing can vary considerably in Nemiana (Vickers-Rich and others, 2010). Other forms other forms from North America, Australia and China, and that well could be of metazoan nature include a possible we suspect that with a larger sample of the Arabian forms, Pteridinium-like form and another possibly related to the this could also be the case. diploblastic-grade metazoan Eoandromeda octobrachiata also known from the late Neoproterozoic of China and GEOLOGIC SETTING Australia (Zhu and others, 2008). In this paper we report a The Jif’n formation in the area where the Holodyskia-like further occurrence of a form Harlaniella, known elsewhere fossil was recovered consists regionally of brown-coloured from late Neoproterozoic successions, a taxon thought to be conglomerates with well rounded pebbles, thin beds of of metazoan grade – either a trace or an imprint of a tubular grey limestone, as wll as dark red weathered calcareous organism and a late occurrence of the enigmatic tissue grade, sandstone and a repeated sequence of grey, clastic sediments possibly metazoan Horodyskia. Also noted are isolated including sandstones, siltstones, thin shales and mudstones. examples of holdfasts (Aspidella), perhaps a Charniodiscus The Horodyskia-like form occurs in a lime-rich dark frond (Nettle, 2009; Johnson and others, 2011 (though this mudstone. Primary structures in the nearby rocks include appears to be ripple marks instead) have been noted from cross- and graded-bedding, ripple marks, and in some cases Jibalah sediments in the Antaq basin in the far east of the mud cracks, all indicative of some subaerial exposure and Arabian Shield. Although we have searched in this region both fl uviate and lacustrine environments. The succession on past expeditions, and though the sediments are ideal for generally is unaffected by deformation striking NNW but preservation of Ediacarans, we have yet to fi nd defi nitive the area has been locally affected by the NW-trending Najd evidence in this sequence. fault system and the sediments remain relatively altered, It is important that the search continues in many which is not often the case with the Jibalah further to the different areas not yet prospected within the Jibalah Group north along strike (Delfour, 1977). sediments and related sequences. A much more detailed The age of these sediments has been placed somewhere search of the Dhaiqa formation in the Al ‘Ula area, to the in the late Neoproterozoic and an ash sample recovered from west and the Jibalah to the south needs to be followed up, a layer near the location where the Horodyskia-like specimen particularly the area where the possible Eoandromeda was was collected and is currently under study by Linnemann recovered and visited again in 2012. Further prospecting and Hofmann to provide. The Dhaiqa sequence, described of the Dhaiqa formation where the Harlaniella, likely above and thought related to the Jif’n formation (Johnson, Cyclomedusa/Aspidella and Charnia were discovered would 2003, 2006) has been dated at 560 ± 4 million (Vickers- be worthy of further investigation. Not yet found is a Rich and others, 2010). biodiverse assemblage that would provide an abundance of

18 Saudi Geological Survey Technical Report - SGS-TR-2013-5 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield specimens which would once and for all establish a record to work with colleagues at the Survey. We also thank the of Ediacarans in the Kingdom. Currently, the record is still National Geographic Society, Monash University, Museum small and in many cases inconclusive. Victoria in Melbourne for their assistance in many ways and The question arises regarding why Ediacaran fossil are several private fi nancial donors who provided travel support. not abundant in sediments of the Arabian Shield whereas, We thank the local people in so many areas that we visited in other parts of the world, such fossil imprints can be in the Kingdom for their friendship and local support, King abundant – such as in Newfoundland, Australia, the White Abdullah University of Science and Technology for inviting Sea of Russia and Namibia. The timing is right with a date some of us to participate in their Winter Enhancement determined and noted in a previous report and another ash Program, and covered travel expenses allowing some of our both in the Dhaiqa providing additional precision (560 ± 4 research colleagues to participate in the fi eld season of 2012. Ma and another at 569 ± 3 Ma) narrowing the diamictites in the Dhaiqa sequence to a post Gaskiers-glaciation, well within the prediction of Miller and others (2008_. REFERENCES Could the absence or rarity of Ediacaran fossils be due to Crimes, T. P., 1992. The record of trace fossils across the the environments being too freshwater? The sequences in Proterozoic-Cambrian Boundary. In: J. H. Lipps and several of the basins studied in this project often were topped P. W. Signor, eds., Origin and Early Evolution of the with carbonates, indicative of a transgression. So, perhaps Metazoa. Plenum Press, New York: 177-202. water chemistry may have been a limiting factor in either Delfour, J., 1977, Geology of the Nuqrah quadrangle, excluding the living Ediacarans and/or perhaps not being sheet 25E, Kingdom of Saudi Arabia: Saudi Arabian conducive to preservation. Miller and others (2008) noted Directorate General of Mineral Resources Geologic “The very highly unradiogenic Sr isotope compositions in Map GM-28, 1 pl. (1:250,000) with text, 32 p., 2 fi gs., the Dhaiqa formation could refl ect retention of primary 16 tables. values in a lacustrine setting dominated by ensimatic Sr input.” They further point out that it could also be due Davies, F.B., 1985, Geologic map of the Al Wajh to extreme alteration of primary marine compositions but quadrangle, sheet 26B, Kingdom of Saudi Arabia: further point out that the high Sr content of the Dhaiqa Saudi Arabian Deputy Minsitry for Mineral Resources carbonates suggest that the 87Sr/86Sr ratios are primary. Geoscience Map GM-83 A (with Landsat Base), GM- Certainly Miller and others (2008) suggest that the 83 C (without Landsat Base), with text, 27 p., 7 fi gs., underlying Mataar formation appears to be fl uvial and not 1 table. marine. Johnson (2003) as well as Johnson and Kattan Fedonkin, M. A., 1981. Belomorskaya biota venda (2001) and Johnson and others (2011) support a shallow (dokembrijskaya besskeletnaya fauna severa Russkoj water or even freshwater origin for many of the Jibalah platformy). Tr. GIN AN SSSR. M. Nauka: 99 pp. sediments evidenced by the purple-brown coloration of many outcrops, the presence of algal-mat carbonates and Fedonkin, M. A., Gehling, J. G., Grey, K., Narbonne, G. sedimentary structures. Johnson (2003) noted “Whether and Vickers-Rich, P., 2007. The Rise of Animals. the basins were lacustrine or marine is not certain, but the Evolution and Diversifi cation of the Kingdom isolated character of each basin and limited thickness of Animalia. Johns Hopkins University Press, Baltimore: the carbonate successions suggest a series of lakes along the 326 pp. controlling faults rather than a marine incursion.” Fedonkin, M. A. and Yochelson, E. L., 2002. Middle So, for now, the puzzle remains of why the Ediacarans Proterozoic (1.5 Ga) Horodyskia moniliformis have not yet been found in abundance in sequences that Yochelson and Fedonkin, the oldest known tissue- are widespread in the Arabian Shield, even though they grade colonial eukaryote. Smithsonian Institution are well known to the southern Africa and other Rodinia Press, Washington: 32 pp. fragments. Perhaps further prospecting will shed light on Gradstein, F., Ogg, J., and Smith, A., (eds.), 2004. A this absence, but for now, one strong possibility is that Geologic Time Scale 2004. Cambridge University the aqueous environments in the late Neoproterozoic in Press, Cambridge:589 pp. this region were just not of the best chemistry to nurture the early development of the oldest metazoans Perhaps Grey, K. and Williams, I. R., 1990. Problematic bedding- conditions were just too fresh, and only time will shed plane markings from the Middle Proterozoic light on this enigma. At the very least, the discovery of Manganese Group, Bangemall Basin, Western genuine metazoan traces does demonstrate that at least Australia. Precambrian Research, 46: 307-327. some animals did inhabit these environments no longer ago Güreev, Yu. A., 1988. Besskeletnaya fauna venda// than 560 million years and now the search is on for more. Biostratigrafi ya I paleogeografi cheskie rekonstruckcii dokembriya Ukrainy. Kiev: Naukova dumka: 65-80. ACKNOWLEDGMENTS Hadley, D.G., 1987, Geologic map of the Sahl al Matran We would like to sincerely thank the Saudi Geological Survey quadrangle, sheet 26C, Kingdom of Saudi Arabia: for their long term commitment to this project, which has Saudi Arabian Deputy Ministry for Mineral Resources continued over more than 4 years in the provision of staff, Geoscience Map GM-86 C (withiout Land Base), with fi eld support and travelling funds to bring international staff explanatory notes, 24 p., 2 fi gs., 2 tables, 1 pl.

Saudi Geological Survey Technical Report - SGS-TR-2013-5 19 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield

Jenkins, R. J. F., 1995. The problems and potential of using Miller, N., Johnson, P. R. and Stern, R. J., 2008, Marine animals fossils and trace fossils in terminal Proterozoic versus non-marine environments for the Jibalah biostratigraphy. Precambrian Research, 73: 51-69. Group, NW Arabian Shield: A sedimentologic and geochemical survey and report of possible metazoan Jensen, S., 2003. The Proterozoic and earliest Cambrian in the Dhaiqa formation. The Arabian Journal for trace fossil record. Patterns, problems and perspectives. Science and Engineering, 33 (1C): 55-77. Integrated Comparative Biology, 43: 219-228. Narbonne, G. M., LeFlamme, M., Greentree, C. and Trusler, Jensen, S. R., Droser, M. L. and Gehling, J.G., 2006. P., 2009, Reconstructing a lost world. Ediacaran A critical look at the Ediacaran trace fossil record. rangeomorphs from Spaniard’s Bay, Newfoundland. In: Xiao, S. and Kaufmann, A. J., Neoproterozoic Journal of Paleontology, 83 (4): 503-523. Geobiology and Paleobiology: Topics in Geobiology, 27, Springer, Heidelberg: 115-157. Narbonne, G. M., Myrow, P. M., Landing, E. and Anderson, M. M., 1987, A candidate stratotype Johnson, P. R., 2003. Post-amalgamation basins of the NE for the Precambrian-Cambrian boundary, Fortune Arabian shield and implications for Neoproterozoic Head, Burin Peninsula, southeastern Newfoundland. III tectonism in the northern East African orogen. Canadian Journal of Earth Sciences, 24: 1277-1293. Precambrian Research, 123 (2003): 321-337. Nicholson, P.G., Janjou, D.L.A., Fanning, C.M., Heaman, Johnson, P.R., 2006, Explanatory notes to the map of L.M. and Grotzinger, J.P., 2008, Deposition, age, Proterozoic geology of western Saudi Arabia: Saudi and Pan-Arabian correlation of late Neoproterozoic Geological Survey Technical Report SGS-TR-2006-4, outcrops in Saudi Arabia (abstract), 8th Middle East 62 p., 22 fi gs., 2 plates. Geoscience Conference and Exhibition, GEO 2008, Johnson, P. R., Anderson, A., Collins, A. S., Fowler, A. Manama, Bahrain AAPG Search and Discovery R., Fritz, H., Ghebreab, W., Kusky, T. and Stern, R. Magazine, article 90077. J., 2011. Late Cryogenian-Ediacaran history of the Nettle, D. 2009. A sequence stratigraphic, geochronological Arabian-Nubian Shield: A review of depositional, and chemostrategrapic investigation of the Ediacaran plutonic, structural, and tectonic events in the closing Antaq basin, Eastern Arabian Shield, Saudi Arabia. stages of the northern East African Orogen. Journal of Geology and Geophysics. Msc thesis, University of African Earth Sciences, 61: 167-232. Adelaide, South Australia: 83 pp. Johnson, P. R. and Kattan, F. H., 2001. Oblique sinistral Palij, V.M., Posti, E. and Fedonkin, M. A., 1979. transpression in the Arabian shield: the timing Myagkotelye metazoan I iskopaemye sledy zhivotnyx and kinematics of a Neoproterozoic suture zone. venda I rannego kembriya // Paleontologiya Precambrian Research, 107: 117-138. vexnedokembrijskix I kembrijskix otlozhenij Johnson, P.R., and Kattan, F.H., 2012, The geology of the Vostochno-Evoropejskoy platformy. M, Nauka, Saudi Arabian Shield. Saudi Geological Survey, 479 p. Moscow, Russia 49-82. Kennedy, A., Kozdroj, W., Johnson, P.R., and Kattan, F.H., Shen, B., Xiao, S., Dong, L., Zhou, C. and Liu, J., 2007. 2011, SHRIMP geochronology in the Arabian Shield Problematic macrofossils from Ediacaran successions Part III: Data acquisition 2006: Saudi Geological in the North China and Chaidam Blocks: Implications Survey Open-File Report SGS-OF-2007-9, 85 p., 89 for their evolutionary roots and biostratigraphic fi gs. 25 tables. signifi cance. Journal of Paleontology, 81 (6): 1396- 1411. Kiryanov, V. V., 1968. Paleontologischeskie ostatki I stratigrafi ya otlozhenij baltijskoj seriiVolyno[Podolii Signor, P. W., 1994. Proterozoic-Cambrian boundary trace // Paleontologiya I stratigrafi ya nizhnego paleozoya fossils: Biostratigraphic signifi cance of Harlaniella in Volyno-Podolii. Naukova dumka, Kiev: 5-27. the Lower Cambrian Wood Canyon formation, Death Valley, California. In: Landing, E., ed., Papers on New Kusky, T.M., and Matsah, M.I., 2003, Neoproterozoic York State Stratigraphy and Paleontology in Honor of dextral faulting on the Najd Fault System, Saudi Arabia, Don Fisher. New York State Museum Bulletin, 491: preceded sinistral faulting and escape tectonics related 347-361. to closure of the Mozambique Ocean, in Yoshida, M., Windley, B.F., and Dasbupta, S (eds), Proterozoic East Sokolov, B. S., 1972. Vendskij etap v istorii Aemli // XXIV Gondwana: Supercontinent Assembly and Breakup. Sessiya Mezhdunar. Geological Kongress, Doklody Geological Society, London, Special Publications 206, Soviet Geology M, Nauka, Moscow, Russia: 177-202. 327-36. Stacey, J.S., and Kramers, J.D., 1975, Approximation of the terrestrial lead isotope evolution by a two-stage model. Meert, J.G., and Lieberman, B.S., 2008, The Neoproterozoic Earth and Planetary Science Letters 26, 207-221. assembly of Gondwana and its relationship to the Ediacaran-Cambrian radiation: Gondwana Research Vickers-Rich, P. and Komarower, P., eds., 2007. The Rise 14: 5-21. and Fall of the Ediacaran (Vendian) Biota. Geological

20 Saudi Geological Survey Technical Report - SGS-TR-2013-5 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield

Society of London, Special Contribution 286, London: Zhu, M., Gehling, J. G., Xiao, S., Zhao, Y. and Droser, 428 pp. M.L., 2008. Eight-armed Ediacara fossil preserved in contrasting taphonomic windows from China and Vickers-Rich, P., Kozdroj, W., Kattan, F. H., Leonov, M., Australia. Geology, 36 (11): 867-870. Ivantsov, A., Johnson, P. R., Linnemann, Ulf, Hofmann, M., Al Garni, S. M., Al Qubsani, A., Shamari, A., Al Barakati, A., Al Kaff, M. H., Ziolkowska-Kozdroj, M., Rich, T. H., Trusler, P. and Rich, B., 2010 (G), 1431 (H). Reconnaissance for an Ediacaran Fauna, Kingdom of Saudi Arabia. Saudi Geological Survey, Technical Report, SGS-TR-2010-8, 42 p., 74 ﬁ gs., 1 table, 1 pl.

EPILOGUE

From science to art to stamps. Research can sometimes lead to art and some of the Ediacaran material now known from Saudi Arabia has been depicted by reconstruction artist and researcher Peter Trusler. The frondlike form from the Dhaiqa is crafted in this art (which led to a stamp issue in Australia in 2005) on the left. With future exploration in the Kingdom, there is hope that more of the Vendian/Ediacaran biodiversity will eventually be discovered.

Saudi Geological Survey Technical Report - SGS-TR-2013-5 21 In Search of the Kingdom’s Ediacarans: The First Genuine Metazoans on the Arabian Shield

22 Saudi Geological Survey Technical Report - SGS-TR-2013-5