Bull. nat. Hist. Mus. Land. (Geol.) 54(2): 131-146 



Issued 26 November 1998 



A review of the stratigraphy and trilobite 

 faunas from the Cambrian Burj Formation in 

 Jordan 



A.W.A. RU SHTON £_ 



Department of Palaeontology, The Natural History Museum, Cromwell Road, London SW7 5BD 



J.H. POWELL 



British Geological Survey, Keyworth, Nottingham, NG12 5GG 



SYNOPSIS. The Burj Formation in Jordan, and its correlatives in surrounding countries, is a Cambrian marine carbonate and 

 siliciclastic deposit which transgressed widely but relatively briefly southwards across theArabian craton. Three members (Tayan 

 Siltstone. Numayri Dolomite and Hanneh Siltstone) are here formally described from outcrops at the southern end of the Dead 

 Sea. Jordan. Trilobites from the Burj Formation are described and are all considered to be earliest Middle Cambrian in age, rather 

 than Lower Cambrian, as previously recorded. 



INTRODUCTION 



The lithostratigraphy of the Cambrian System in Jordan has been 

 studied extensively (Bender 1974; Powell 1989). In outline, 

 Neoproterozoic complexes (Ibrahim & McCourt 1995) are overlain 

 by the Ram Group, which consists dominantly of sandstone units 

 and includes a fossiliferous carbonate-rich intercalation now known 

 as the Burj Formation. Faunas from the Burj were examined by 

 various workers who tentatively assigned early to mid- or late 

 Cambrian and Ordovician ages to them. Contemporaneous beds 

 which crop out at Timna in the southern Negev (south Israel) have 

 been reviewed by Weissbrod (1970) and Parnes (1971); the Timna 

 outcrop is generally accepted as being offset from the Dead Sea 

 outcrop in Jordan by a left-lateral (sinistral) displacement of approxi- 

 mately 105 km along the Dead Sea - Gulf of Aqaba Rift fault 

 (Freund etai, 1970). 



Brachiopods and trilobites recorded from the Burj Formation by 

 Blanckenhorn (1912, 1914) were described by Richter & Richter 

 (1941), who reviewed other work in that region. They rejected 

 earlier opinions that the faunas ranged in age from early in the 

 Cambrian to Ordovician, and regarded the records known to them as 

 close to the Lower-Middle Cambrian boundary, and probably high- 

 est Lower Cambrian. Parnes (1971) described further material, 

 especially from the southern Negev, and reviewed earlier work. 

 After comparing material from the east side of the Dead Sea and 

 fromTimna in the southern Negev with Hupe"s faunal succession for 

 Morocco ( Hupe 1 960), he proposed a more elaborate biostratigraphy 

 extending through much of the Lower Cambrian. Cooper (1976) 

 studied the brachiopod faunas and relied on Parnes' work to indicate 

 their late Early Cambrian age. 



Subsequent seismic studies and the examination of deep boreholes 

 has greatly extended knowledge of the Cambrian succession in 

 Jordan (Andrews 1991 (.Although the macrofossils were considered 

 to indicate a late Early Cambrian age for the formation, marine 

 palynomorphs described from boreholes NH-1. TS-11, WS-3 in 

 Jordan (Fig. 2), occurring in palynozone JC-1 of Keegan el al. 

 (1990), were assigned an early Middle Cambrian age, especially on 

 account of the occurrence of acritarchs known from the Oville 

 Formation in Spain, which is assigned to the Leonian Stage (Table 1 ) 

 and the overlying Caesaraugustian Stage (Linan et al. 1993). 



Whilst these reports suggested that the biostratigraphy of the 

 Cambrian rocks of Jordan and Israel is complex, sedimentological 

 syntheses, coupled with work on trace fossils, supported a relatively 

 simple model in which a Cambrian marine transgression introduced 

 a tongue of marine strata onto the Arabian craton (Selley 1972; 

 Amireh et al. 1994), though those authors did not attempt to 

 integrate their syntheses with the known biostratigraphy. 



We have examined new material from the Dead Sea area and 

 reviewed older work, especially in the light of recent study of the 

 Moroccan sequences (Geyer 1990a. 1990b; Sdzuy 1995), and be- 

 lieve that the palaeontological evidence can be reconciled with the 

 recent stratigraphical and sedimentological syntheses. We conclude 

 (following Amireh et al. 1994) that near the beginning of Middle 

 Cambrian times a marine incursion transgressed from the north or 

 north-west onto earlier Cambrian fluviatile deposits on the Arabian 

 craton. It introduced various lithofacies comprising locally 

 fossiliferous shallow-water carbonate and siliciclastic deposits. Soon 

 afterwards a fall in sea-level and increased sediment from the 

 Arabian craton resulted in a return to fluviatile sedimentation which 

 continued in central-south Jordan until the Ordovician. 



LITHOSTRATIGRAPHY 



Localities. Owing to a lack of a standard transliteration of 

 Arabic place names, confusion has arisen regarding the names of 

 wadis and other features referred to by various authors (for example 

 Wadi Qunai has been recorded as Wadi Quni. Wadi Kneye, Wadi 

 Gineya). We adopt the standard names used by the Geology Direc- 

 torate, Natural Resources Authority, Jordan. 



Localities studied during this work are located to within 500 m 

 using the Palestine National Grid (PNG). Localities referred to by 

 previous authors are not always precise, and here we have endeav- 

 oured to give a grid reference based on their descriptions. 



Burj Formation 



The Burj Dolomite-Shale Formation, hereafter referred to as the 

 Burj Formation, forms a prominent cliff-like feature between the 

 siliciclastic Salib Arkose and Umm Ishrin formations in the type 



©The Natural History Museum. 1998 



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