Studi Perubahan Lingkungan di Situs Arkeologi Kumitir Mojokerto Berdasarkan Analisis Stratigrafi, Palinologi, Ukuran Butir Sedimen, dan Geokimia XRF

Tasyafah Nurbasitha Hidayat, Dr. Eng. Ir. Akmaluddin, S.T., M.T., IPM.

2026 | Skripsi | TEKNIK GEOLOGI

Penelitian yang dilakukan di Situs Arkeologi Kumitir, Mojokerto, Jawa Timur bertujuan untuk mengetahui susunan stratigrafi, paleovegetasi, perubahan lingkungan, serta mengidentifikasi keberadaan struktur bangunan, indikasi aktivitas budidaya tumbuhan, dan umur absolut situs. Penelitian dilakukan dengan berbagai macam metode analisis meliputi analisis stratigrafi terukur, palinologi, ukuran butir sedimen, X-Ray Flourescence (XRF), dan penanggalan radiokarbon. Data stratigrafi terukur digunakan dalam pengorelasian dan penyusunan kolom stratigrafi daerah penelitian. Kemudian, data sampel yang diambil merupakan sampel boks 1-A untuk pengamatan palinologi, ukuran butir sedimen, dan geokimia XRF, serta sampel dating L1 dan L2 untuk penanggalan radiokarbon. Hasil penelitian menunjukkan bahwa susunan stratigrafi daerah penelitian tersusun oleh batupasir-1 (Bp-1), paleosol-1 (P-1), tuf-1 (T-1), paleosol-2 (P-2), tuf-2 (T-2), endapan lahar-1 (Eh-1), batupasir-2 (Bp-2), paleosol-3 (P-3), batupasir kerikilan (Bpk), endapan lahar-2 (Eh-2), endapan lahar-3 (Eh-3), paleosol-4 (P-4),  endapan kerikil-berangkal (Ekb), tanah situs (Ts), dan material situs berfragmen bongkah-berangkal (Msb), serta terdapat dua struktur bangunan yaitu struktur batubata-1 (Sbt-1) dan struktur batubata-2 (Sbt-2). Paleovegetasi daerah penelitian menunjukkan ekosistem lingkungan hutan terbuka, dengan dominasi tumbuhan kelompok padang rumput dan jenis polen NAP yang tinggi. Sementara itu, perubahan lingkungan pada daerah penelitian dikontrol oleh sistem fluvial dan aktivitas vulkanik pada setting pengendapan kipas aluvial zona proksimal hingga distal. Lebih lanjut, struktur batubata yang ditemukan di sekitar situs diperkirakan dibangun setelah abad ke-12 M dan abad ke-16 M. Kemudian, aktivitas budidaya tumbuhan telah berlangsung pada lingkungan sekitar situs, diperkirakan berkembang pada rentang ? 1090-1259 M, dibuktikan dengan hadirnya polen Oryza type, Piperaceae, Myrtaceae, Moraceae, dan Mimusops (Sapotaceae).

Research conducted at the Kumitir Archaeological Site in Mojokerto, East Java, aims to determine the stratigraphic succession, paleovegetation, and environmental changes, as well as to identify the presence of architectural structures, indications of plant cultivation activities, and the absolute dating of the site. This study employed a multi-proxy analytical approach, including measured stratigraphic sections, palynology, grain-size analysis, X-Ray Fluorescence (XRF), and radiocarbon dating. Measured stratigraphic data were used in the correlation and construction of the stratigraphic column of the study area. The samples collected consist of box core samples 1-A for palynological, sediment grain size, and XRF geochemical observations, as well as dating samples L1 and L2 for radiocarbon dating. The results indicate that the stratigraphic succession of the study area is composed of sandstone-1 (Bp-1), paleosol-1 (P-1), tuff-1 (T-1), paleosol-2 (P-2), tuff-2 (T-2), lahar deposit-1 (Eh-1), sandstone-2 (Bp-2), paleosol-3 (P-3), gravelly sandstone (Bpk), lahar deposit-2 (Eh-2), lahar deposit-3 (Eh-3), paleosol-4 (P-4), gravel-cobble deposit (Ekb), site soil (Ts), and boulder-cobble fragmented site material (Msb), along with two architectural structures, namely brick structure-1 (Sbt-1) and brick structure-2 (Sbt-2). The paleovegetation of the study area reflects an open forest environment, characterized by the dominance of grassland group and a high proportion of non-arboreal pollen (NAP). Furthermore, environmental changes in the study area were primarily controlled by fluvial systems and volcanic activity within the proximal to distal  zones of an alluvial fan depositional setting. The brick structures are estimated to have been constructed after the 12th century CE and the 16th century CE. Evidence of plant cultivation has been identified in the site’s vicinity, estimated to have developed around ? 1090–1259 AD, as evidenced by the presence of Oryza-type, Piperaceae, Myrtaceae, Moraceae, and Mimusops (Sapotaceae) pollen.

Kata Kunci : Geoarkeologi, Lingkungan Pengendapan, Palinologi, Situs Kumitir, Stratigrafi