Studi Fasies Formasi Endapan Danau Untuk Menentukan Lingkungan Pengendapan Danau Limboto

Abstract

The research area located in the lowland zone and the corrugated hilly zone which is dominated by sedimentary rocks. Therefore, this study aims to determine the geological features of the research area and the study of depositional environmental facies of the Lake Deposits Formation as an analysis of the depositional environment of Limboto Lake. The research method used is the surface geological mapping, measuring section of stratigraphic and laboratory analysis. Field data consists stratigraphycal features of research area. Laboratory analysis consists of petrography and stratigraphy-sedimentology analysis. It can be concluded facies and stratigraphy of research from older to youngest, consists of clastic limestones unit formed in Late Miocene-late Early Pliocene age, reef limestones formed in Late Miocene-early Late Pliocene age, sandstones unit formed in Late Pliocene-Pleistocene age, clay unit and sandy clay unit are deposited in Holocene. Overall the study site consisted of marine, transitional and terrestrial deposition environment with Lake Deposits Formation facies is lake margin clastic deposits and meandering-stream environment deposits.

Analisis Petrografi Dan Sebaran Litologi Daerah Saripi Dan Sekitarnya, Kecamatan Paguyaman, Kabupaten Boalemo, Provinsi Gorontalo

“…Pengaruh gerak lempeng-lempeng tektonik tersebut menyebabkan Sulawesi memiliki bentuk unik yang menyerupai huruf K. Bukti pengaruh tektonik di wilayah ini berupa pengangkatan di utara Cekungan Limboto yang kini tersingkap ke permukaan dengan kecepatan pengangkatan 0,06990-0,0724 mm/tahun (Permana et al, 2021). Cekungan Limboto merupakan depression basin dibentuk oleh ekspansi Neogene, yang menyebabkan terjadinya tumbukan dan penyebaran zona sesar besar dan subduksi Busur Banda dari miosen awal hingga pertengahan (Amin et al, 2019). Kegiatan vulkanik dan plutonik membawa pengaruh besar di lengan utara Sulawesi, salah satunya adalah penyebaran batuan beku vulkanik maupun plutonik yang menguasai mayoritas luas wilayah ini.…”

Mechanism of the Rapid Shrinkage of Limboto Lake in Gorontalo, Indonesia

“…Herein, the stratigraphy of river outcrops and the lowland plain area was explored from a geological perspective. Furthermore, a typical geologic columnar section was produced at thirty outcrops along the Alopohu river by specifying the results of a previous study [16]. The results are compared with the sedimentation components of the lake studied by [17] and are also used to explain the shrinkage mechanism of Limboto Lake in further discussion.…”

“…Therefore, the sedimentary environments of outcrops along the riverbank and lowland plain areas were investigated. Based on previous research [16], a typical geologic columnar section at thirty outcrops along the Alopohu river was modified in this study as described in Figure 8.…”

Petrography Characteristic of Porphyritic Dacite Rock in Olele Village, Kabila Bone, and Bone Bolango

“…The complex tectonic setting of North Arm Sulawesi made research location located in a volcanic-plutonic belt which is predominated by Eocene to Pliocene volcanic rock [8][9]. The complex tectonic settings of Gorontalo also made some parts of this area uplifted, example Limboto Lake which is are marine depositional zone at Late Miosen-Early Pliocene with brackish lagoons and estuaries ancient environment [10][11]. The abundance of coral limestone in Gorontalo [12] also proves this area is an uplifted marine depositional zone.…”