# Diagenetic Study of Marron Emperador Ornamental Stone (Upper Cretaceous, SE Spain)
## 1 Introduction  
Brecciated carbonate rocks, including dolostones, are relatively abundant in geological records and commonly host economic deposits, such as exhalative sedimentary (SEDEX) zinc-lead deposits or constitute important hydrocarbon reservoirs [1; 2; 3; 4; 5]. In addition, carbonate breccia constitutes a type of ornamental rock widely used for decorative and architectural purposes since historical times, given its particular and attractive visual appearance [6]. Dolomitic breccia usually are the result of a complex diabetic history that is responsible not only for their nature, but also for their aesthetic quality properties [7].  
Several models have been proposed to explain both dolomitization and brecciation processes in the genesis of dolostone breccia geobodies, such as solution collapse, compactional dewatering or burial and fault-controlled hydrothermal [4; 8; 9; 10; 11; 12; 13; 14; 15]. Massive dolomites generally have important tectonic control, are commonly formed in extensional settings (structurally controlled dolomites, SCD) and usually involve hot fluids formed when the fluids have a temperature higher than the host rock [1; 2; 3; 10; 13; 15; 16; 17; 18; 19]. Breccia in SCD generally occurs proximal to faults [3; 11] and is commonly attributed to hydrofracturing [20; 21]. Dolostone geobodies resulting from fault-associated replacement processes commonly are irregular in geometry and are distributed in patches along the fault trace [12; 17; 22; 23; 24; 25] or result in a stratabound distribution [17; 24; 26; 27; 28].  
Marron Emperador (ME) ornamental stones are Mesozoic brown breccated dolostones with high structural and textural complexities quarried in a wide area along the external Prebetic Domain (southeast Spain) [29; 30]. Due to the attractive appearance of the darkdolostone clasts within the white sparry calcite, this breccia has been widely used as a dimension stone [29; 31; 32]. According to the MIA classification (Marble Institute of America) [14], these materials belong to Group C, which corresponds to commercial marbles with some variations in their physical properties. The technological properties of ME dolostone vary according to varieties or commercial categories [29; 30; 32; 33; 34; 35] (Table 1). In previous works [7; 36], the mineralogical, geochemical and petrological factors that affect or control the aesthetic quality parameters of ME ornamental stone were studied. Results showed that diagenetic processes are mainly responsible for the colour of ME dolostones, revealing that the Sr content is a key factor. Likewise, results also showed that other compositional or textural factors, such as dolomite stoichiometry or the type of dolospar mosaics, do not clearly control the main aesthetic quality properties of ME ornamental stone. This reflects that the formation of the ME dolostone geobody results from complex multiphase diagenetic processes. This paper presents new petrographic and geochemical data on the ME brecciated dolostones. The main objective of the study is to unravel the diagenetic evolution of the carbonate host rock with special emphasis on determining the main factors (composition and origin of the dolomitizing fluids, brecciation style, etc.) that control both the dolomitization and brecciation processes.