## 1 Introduction  
Cave sediments are one of the best archives of geological, paleoenvironmental, and geleogenetic processes [1, 2]. Climate conditions within caves are much more stable than those on the Earth's surface, making them intriguing areas for field research. These environments provide valuable insight from geological [3, 4], physical [5], and biological, particularly paleontological [6, 7] perspectives. The Dinaric Karst is known for its well-developed profiles of allogenic cave sediments [8]. However, these deposits in the Croatian part of the Dinaric Karst are poorly investigated. Most previous research has focused on paleontological excavations [9]. Recently, there has been an increased focus on sedimentological and mineralogical research and establishing a chronost stratigraphic framework for depositional processes [10]. In the northwestern part of the Dinaric Karst, there is a well-developed magnetostratigraphy-raphy of cave deposits [11]. However, research on magnetism and magnetic susceptibility in caves within the Republic of Croatia is significantly lacking. Magnetic susceptibility serves as a valuable metric of a material's magnetism, offering diverse analytical advantages. It aids in identifying minerals rich in magnetism within samples, enabling high-resolution determination of their concentration or total volume. Furthermore, it assists in classifying different rock types and understanding their formation or transport processes, while also facilitating the creation of an \"environmental fingerprint\" [12]. It is most commonly used in studies of igneous rocks [13]. Magnetic susceptibility represents the aggregate magnetic behavior of rocks, known as rock magnetism, from various components including ferromagnetic, ferrimagnetic, canted antiferromagnetic, paramagnetic, and diamagnetic groups. Measuring magnetic susceptibility is straightforward, convenient, and versatile [14]. It can be carried out on all types of rocks, both in the laboratory and in the field, with minimal preparation. These measurements are quick, non-destructive, and complement a wide range of studies. Moreover, a large number of samples can be economically measured without restricting subsequent research. In situ measurements expedite the integration of measured data and field observations, proving particularly beneficial for individuals in remote areas lacking laboratory access. Given that Croatian allogenic cave sediments originate from various provenance areas, their mineral detritus often exhibits diverse mineral composition, and, therefore, diverse magnetic properties. In the area of Velebit Mountain, particularly near the former Kita Gacesina Cave, which is today a part of the Crnopac Cave System, there are documented occurrences of opaque mineral fractions, as well as pyroxene, chromite and biotite [10]. Additionally, calcium carbonate is expected, given that the speleogenesis of the area is primarily connected to the thick sequence of Mesozoic carbonate host rock of the Adria Microlate [15; 16; 17; 18]. The presence of allogenic sediments in Velebit caves that contain both carbonate clasts and heavier mineral fractions suggests that both paramagnetic and diamagnetic materials are likely present in these caves. The research area is located within Dinaric Karst which is _locus typicus_ for global karst evolution and geomorphology [19]. This study aimed to investigate the possibility of precise measurement of magnetic susceptibility in caves in Velebit Mountain. This study also aimed to establish whether significant changes in magnetic susceptibility were accompanied by variations in mineral composition. Furthermore, a statistical analysis was conducted between in situ and laboratory results to evaluate the compatibility of the two devices. In situ measurements utilized the Kappameter KM-7 device from SatisGeo s.r.o. (Brno, Czech Republic), while laboratory measurements employed the Bartington MS2B System (Bartington Instruments, Oxford, UK).