Hasil Pencarian  ::  Simpan CSV :: Kembali

"This book presents a comprehensive, contemporary review of tidal environments and deposits. Individual chapters, each written by world-class experts, cover the full spectrum of coastal, shallow-marine and even deep-marine settings where tidal action influences or controls sediment movement and deposition. Both siliciclastic and carbonate deposits are covered. Various chapters examine the dynamics of sediment transport by tides, and the morphodynamics of tidal systems. Several chapters explore the occurrence of tidal deposits in the stratigraphic context of entire sedimentary basins. "

"Studi paleoklimatologi penting untuk memahami perubahan iklim masa lalu yang tidak tercatat secara instrumental dan menjadi dasar untuk memprediksi pola iklim masa depan. Penelitian ini bertujuan merekonstruksi kondisi paleoklimat di Perairan Utara Jayapura berdasarkan salah satu core dengan kode “UP”. Daerah Perairan Utara Jayapura merupakan salah satu pintu masuk Arlindo (Arus Lintas Indonesia) yang merupakan bagian dari sirkulasi perairan global, sehingga diperkirakan mampu merekam jejak perubahan iklim global. Analisis dilakukan secara multiproksi, meliputi distribusi ukuran butir, LOI (Loss on Ignition), unsur jejak (XRF), dan kelimpahan foraminifera. Hasil menunjukkan dominasi sedimen lempung dan lanau berbutir kasar, dengan struktur masif dan menyerpih. Stratigrafi vertikal menunjukkan perubahan energi pengendapan dari stabil ke dinamis. Peningkatan unsur Fe dan Ti di bagian dangkal menunjukkan peningkatan input daratan akibat curah hujan. Penanggalan relatif terhadap data radiokarbon menunjukkan umur sampel 13.625 BP (Pleistosen Akhir), dengan batas Holosen pada kedalaman 92 cm (~11.500 BP). Setelah batas tersebut, terjadi lonjakan kelimpahan foraminifera dominan seperti Globigerina bulloides, Globigerinoides ruber, Bolivina robusta, dan Trilobatus immaturus. Berdasarkan komposisi foraminifera dan indikator lingkungan, paleoklimat direkonstruksi dalam tiga periode: Pre-Holocene Climate Optimum (13.625–11.875 BP), Holocene Climate Optimum (11.625–9.125 BP), dan Post-Holocene Climate Optimum (8.875–0 BP), yang masing-masing mencerminkan variasi suhu, curah hujan, oksigen, kedalaman termoklin, dan dinamika sedimen sejak Pleistosen Akhir hingga Holosen.

---

Paleoclimatology studies are important for understanding past climate changes that are not recorded instrumentally and as a basis for predicting future climate patterns. This study aims to reconstruct paleoclimate conditions in the North Jayapura Waters based on one of the marine sedimentary core coded "UP". The Northerm Jayapura Waters area is one of the entrances of ITF (Indonesian Through Flow) which is part of the global water circulation, so it is estimated to be able to record traces of global climate change. The analysis was carried out using a multiproxy method, including grain size distribution, LOI (Loss on Ignition), trace elements (XRF), and foraminifera abundance. The results show the dominance of coarse-grained silt sediments, with massive and flaky structures. Vertical stratigraphy shows changes in depositional energy from stable to dynamic. Increased Fe and Ti elements in the shallow part indicate increased land input due to rainfall. Relative dating to radiocarbon data shows the age of the sample is 13,625 BP (Late Pleistocene), with the Holocene boundary at a depth of 92 cm (~11,500 BP). After this boundary, there is a surge in the abundance of dominant foraminifera such as Globigerina bulloides, Globigerinoides ruber, Bolivina robusta, and Trilobatus immaturus. Based on the composition of foraminifera and environmental indicators, the paleoclimate is reconstructed into three periods: Pre-Holocene Climate Optimum (13,625–11,875 BP), Holocene Climate Optimum (11,625–9,125 BP), and Post-Holocene Climate Optimum (8,875–0 BP), which reflect the variations in temperature, precipitation, oxygen, thermocline depth, and sediment dynamics from the Late Pleistocene to the Holocene, respectively."

"A sedimentology survey was conducted during “Pelayaran Kebangsaan� research activities with a marine vessel of "Baruna Jaya VIII" in Karimun Java Sea. The objectives of the research were to determine the characteristics of marine water and its sediment, which are important control for coral reef growth in the study area. The survey acquired samples of Total Suspended Sediment (TSS) and gravity coring. Several analyses were then carried out on those samples; TSS analysis to determine the amount of suspended sediments in sea water that reflect the water quality for marine ecology, stratigraphic profile and sediment thickness pattern analyses to determine the sources of sediment, and grain-size analysis based on granulometry to determine deposition energy and grain-size distribution in the area. Those analyses were both conducted on-board Baruna Jaya VIII research vessel and P2O LIPI laboratory in Jakarta. The results showed that in Java Sea nearby Karimun Java Islands, the sediment supply came from the surrounding islands. Two sedimentary units were found in this area. The first units has thickness of tens centimeter from sea bed surface. It is characterized by grayish green color, grain size variation from clay to coarse sand, soft or low density and abundance with shells. The second unit is located beneath the first one, indicated by sharp contact. It is characterized by brownish color, higher density resembling the density of rock, less compacted and can be broken easily by hand, with occasionally thin carbon lenses or remnant of decomposed vegetation, and less shell or fossil At sea surface, TSS distribution shows value between 0.018 and 0.034 gr/l, with average of 0.025 gr/l, whereas at near bottom sea, it ranges between 0.024 and 0.030 gr/l, with average value of 0.027 gr/l. The granulometry shows that more than 50% of sediment is characterized by the abundance of grain size greater than 3 phi. It suggest that sea water around Karimun Java Islands was clear and the current was relatively calm. These conditions were relatively stable for a long time span. Those sea characteristics were important for successful growth of coral reefs and its complementary marine biotas. However, further studies and researches based on chemical and physical characteristics of sea water, and plankton and microbiology variation and abundances are necessary to confirm those presuppositions"

"Perubahan dalam lingkungan oleh aktivitas manusia dapat berasosiasi dengan akumulasi logam berat dan berpotensi meninggalkan jejak antropogenik dalam rekaman sedimen laut. Penelitian akan kondisi kemostratigrafi dilakukan untuk menentukan pengaruh aktivitas antropogenik di Perairan Banggai, yang dinilai tinggi karena fungsinya sebagai wilayah penangkapan ikan dan berdekatan dengan Pulau Taliabu, kepulauan agrikultural dengan potensi tambang yang tinggi. Penelitian ini dilakukan dengan melakukan penanggalan umur (dating) dengan isotop 210Pb, analisis logam berat, distribusi ukuran butir, dan kandungan TOC untuk menganalisis dan merekonstruksi perubahan lingkungan. Penanggalan menggunakan isotop 210Pb dilakukan menggunakan spektrometer alfa (AAS), logam berat dianalisis menggunakan spektrometri emisi optikal (ICP-OES), distribusi ukuran butir dianalisis menggunakan difraksi laser (LDS), dan kandungan TOC dianalisis menggunakan LOI. Hasil analisis menunjukkan bahwa distribusi konsentrasi logam berat dalam sedimen core BC-06 menghasilkan nilai geo-accumulation index dan enrichment factor yang rendah, dan menunjukkan bahwa sumber logam berat yang ditemukan merupakan campuran alamiah dan antropogenik. Jejak logam berat dengan pengaruh antropogenik dalam sedimen core BC-06 dapat dibagi menjadi tiga periode, yaitu: (I) 1831-1927 AD, (II) 1927-1994 AD, dan (III) 1994-2022 AD, yang diinterpretasi berhubungan dengan ekspansi militer pada zaman pemerintahan Hindia-Belanda dan perkembangan berbagai sektor perekonomian Indonesia modern.

---

Changes in the environment by human activities is associated with heavy metal accumulation and can potentially leave anthropogenic traces in marine sediment records. Research focusing on the chemostratigraphic condition was done to determine the impacts made by anthropogenic activities in Banggai Waters, that are considered high because of its function as fishing grounds and is located near Taliabu Islands, which are agricultural lands with high mining potential. This research was done by Pb-210 dating, heavy metal, grain size distribution, dan TOC content analyses, to analyse and reconstruct environmental changes. Pb-210 dating was conducted by alpha spectrometer (AAS), heavy metal analysis was conducted by optical emission spectrometry (ICP-OES), grain size distribution analysis was conducted by laser diffraction (LDS), and TOC content analysis was conducted by the LOI method. Results show that heavy metal concentration distribution in sediment core BC-06 yield low values for geo-accumulation index (Igeo) and enrichment factor (EF), and showed that the metals found has a mixed source of natural and anthropogenic. Heavy metal traces with anthropogenic influence can be divided into three periods, such as: (I) 1831-1927 AD, (II) 1927-1994 AD, dan (III) 1994-2022 AD, which are interpreted as related to the military expansion during The Dutch’s colonialism, alongside the development of various economic sectors in modern Indonesia."

"This volume consists of the latest scientific research by international experts in geological, geophysical, engineering and environmental aspects of submarine mass failure, focused on understanding the full spectrum of challenges presented by submarine mass movements and their consequences."