Description: Early‐diagenetic cementation of tropical carbonates results from the combination of numerous physico‐chemical and biological processes. In the marine phreatic environment it represents an essential mechanism for the development and stabilization of carbonate platforms. However, diagenetic cements that developed early in the marine phreatic environment are likely to become obliterated during later stages of meteoric or burial diagenesis. When lithified sediment samples are studied, this complicates the recognition of processes involved in early cementation, and their geological implications. In this contribution, a petrographic microfacies analysis of Holocene Halimeda segments collected on a coral island in the Spermonde Archipelago, Indonesia, is presented. Through electron microscopical analyses of polished samples, this study shows that segments are characterized by intragranular cementation of fibrous aragonite, equant High‐Mg calcite (3.9 to 7.2 Mol% Mg), bladed Low‐Mg calcite (0.4 to 1.0 Mol% Mg) and mini‐micritic Low‐Mg calcite (3.2 to 3.3 Mol% Mg). The co‐existence and consecutive development of fibrous aragonite and equant High‐Mg calcite results initially from the flow of oversaturated seawater along the aragonite template of the Halimeda skeleton, followed by an adjustment of cement mineralogy towards High‐Mg calcite as a result of reduced permeability and fluid flow rates in the pores. Growth of bladed Low‐Mg calcite cements on top of etched substrates of equant High‐Mg calcite is explained by shifts in pore water pH and alkalinity through microbial sulphate reduction. Microbial activity appears to be the main trigger for the precipitation of mini‐micritic Low‐Mg calcite as well, based on the presumable detection of an extracellular polymeric matrix during an early stage of mini‐micrite Low‐Mg calcite cement precipitation. Radiocarbon analyses of five Halimeda segments furthermore indicate that virtually complete intragranular cementation in the marine phreatic environment with thermodynamically/kinetically controlled aragonite and High‐Mg calcite takes place in about 100 years. Collectively, this study shows that early‐diagenetic cements are highly diverse and provides new quantitative constraints on the rate of diagenetic cementation in tropical carbonate factories.

Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659

Description: https://doi.pangaea.de/10.1594/PANGAEA.923980

Description: The shoreline analysis of the reef island Langkai, SW Sulawesi, Indonesia is based on satellite images from 1999-2023. Transects (n=306) were used for shoreline analysis. Net shoreline movement and end point rate at each transect were calculated with the Digital Shoreline Analysis Tool (Thieler et al., 2009) in ArcGIS.

Description: The data set includes grain size distribution of sediments from the reef island Langkai, SW Sulawesi, Indonesia. The data was collected in order to reconstruct the Holocene and modern (sediment) dynamics over the past ca 6,000 years. Sediment samples were obtained from sediment cores taken by percussion drilling and hand-held (Auger) coring in May 2016 and July 2021. Laboratory analysis of the sediments and shoreline analysis were carried out between 2021 and 2023. The grain size distribution was determined by dry-sieving of the bulk sample into fractions following Wentworth (1922).

Description: The data set includes facies compositions of sediments from the reef island Langkai, SW Sulawesi, Indonesia. The data was collected in order to reconstruct the Holocene and modern (sediment) dynamics over the past ca 6,000 years. Sediment samples were obtained from sediment cores taken by percussion drilling and hand-held (Auger) coring in May 2016 and July 2021. Laboratory analysis of the sediments and shoreline analysis were carried out between 2021 and 2023. The skeletal components of the grain size fractions 〉2 mm, 2-1 mm, 1-0.5 mm and 0.5-0.25 mm were analyzed under a digital microscope by point counting. A total of n=100 skeletal components were identified from each fraction.

Description: The data set includes relative facies composition in sediments from the reef island Langkai, SW Sulawesi, Indonesia. The data was collected in order to reconstruct the Holocene and modern (sediment) dynamics over the past ca 6,000 years. Sediment samples were obtained from sediment cores taken by percussion drilling and hand-held (Auger) coring in May 2016 and July 2021. Laboratory analysis of the sediments and shoreline analysis were carried out between 2021 and 2023. The skeletal components of the grain size fractions 〉2 mm, 2-1 mm, 1-0.5 mm and 0.5-0.25 mm were analyzed under a digital microscope by point counting. A total of n=100 skeletal components were identified from each fraction. These results were then used to calculate the relative proportions in each sample.

Description: The shoreline analysis of the reef island Langkai, SW Sulawesi, Indonesia is based on 11 satellite images from 1999-2023. Island surface area was retrieved with the Digital Shoreline Analysis Tool (Thieler et al., 2009) in ArcGIS.

Description: The dataset is based on 50 soft carbonate sediment samples from the reef island Barrang Lompo in the Spermonde Archipelago, Sulawesi, SE Asia. The subsurface samples were obtained by percussion drilling at 5 coring locations on the island. From each coring location, 10 samples were retrieved in 1 m intervals, thus providing samples from a maximum depth of 10 m below surface at each site (1 m, 2 m, ..., 10 m). Laboratory data was collected between 2019 and 2021. The provided dataset contains processed grain size data using GRADISTAT by Blott & Pye (2001). The collected data provides information of reef-derived sedimentation in the Holocene in the Spermonde Archipelago.

Description: The dataset is based on 50 soft carbonate sediment samples from the reef island Barrang Lompo in the Spermonde Archipelago, Sulawesi, SE Asia. The subsurface samples were obtained by percussion drilling at 5 coring locations on the island. From each coring location, 10 samples were retrieved in 1 m intervals, thus providing samples from a maximum depth of 10 m below surface at each site (1 m, 2 m, ..., 10 m). Laboratory data was collected between 2019 and 2021. The provided dataset contains the classification of facies. Percentages of compositions in samples were calculated by adding up relative counts of skeletal components for each samples (i.e. 200 components from fraction 〉2 mm plus 200 from fraction 2-1 mm plus 100 from fraction 1-0.5 mm). The collected data provides information of reef-derived sedimentation in the Holocene in the Spermonde Archipelago. It provides insight into the ecological background and the origin of the skeletal sediments.

Description: The dataset is based on 50 soft carbonate sediment samples from the reef island Barrang Lompo in the Spermonde Archipelago, Sulawesi, SE Asia. The subsurface samples were obtained by percussion drilling at 5 coring locations on the island. From each coring location, 10 samples were retrieved in 1 m intervals, thus providing samples from a maximum depth of 10 m below surface at each site (1 m, 2 m, ..., 10 m). Laboratory data was collected between 2019 and 2021. The provided dataset contains raw and calibrated radiocarbon ages from 20 selected samples (Marine20 calibration curve by Heaton et al. 2020; marine reservoir correction by Southon et al. 2002; calibration tool OxCal v4.4 by Bronk Ramsey, 2009; delta R = 0). For the radiocarbon analyses, picked and pooled Foraminifera of the genus Calcarina were dated in Poznan Radiocarbon Laboratory. The calibrated ages cover the earlier to late Holocene (~7,000 to 2,000 years BP). The collected data provides information of reef-derived sedimentation in the Holocene in the Spermonde Archipelago. It provides insight into the ecological background and the origin of the skeletal sediments.

Description: The dataset is based on 50 soft carbonate sediment samples from the reef island Barrang Lompo in the Spermonde Archipelago, Sulawesi, SE Asia. The subsurface samples were obtained by percussion drilling at 5 coring locations on the island. From each coring location, 10 samples were retrieved in 1 m intervals, thus providing samples from a maximum depth of 10 m below surface at each site (1 m, 2 m, ..., 10 m). Laboratory data was collected between 2019 and 2021. The provided dataset contains raw grain sizes determined after dry sieving. Samples were weighed before sieving (initial mass). After sieving, fractions (diameters from 32 mm to 0.0063 mm) from each sieve were weighed to analyze grain size distribution. The collected data provides information of reef-derived sedimentation in the Holocene in the Spermonde Archipelago.