Gravity Data Analysis on the Emergence of the Nanggulan Formation in Kulon Progo Mountain

Muhammad Faizal Zakaria; Sari Bahagiarti  Kusumayudha; Y.  Yatini; Ismail  Mutoriz; Bobby  Wijaya

Article Details

Gravity Data Analysis on the Emergence of the Nanggulan Formation in Kulon Progo Mountain

Authors:

Muhammad Faizal Zakaria | Sari Bahagiarti Kusumayudha | Y. Yatini | Ismail Mutoriz | Bobby Wijaya

Publisher:

Iraqi Geologists Union (Union of Iraqi Geologists)

Journal:

The Iraqi Geological Journal Vol.58 Issue 2C, pp.202-214

Document Type:

Article

Publication Date:

9/2025

Document Language:

English

Document ID (Org No.):

2001836882

pISSN:

2663-8754

Keywords:

Abstract:

 This study investigates the uplifting mechanism of the Nanggulan Formation, the oldest geological unit in the eastern flank of the Kulon Progo Mountains, Central Java, using gravity data analysis. Gravity measurements were conducted over a 14 × 8 km² area with 118 measurement points. Data acquisition utilized a LaCoste and Romberg G-1118 gravimeter in combination with geodetic GPS, and the collected data were processed to produce a Complete Bouguer Anomaly map. Forward modeling was applied to interpret subsurface structures and identify possible uplift mechanisms. The gravity anomaly map shows high anomalies in the northwest, corresponding to the Jonggrangan Formation, and in the eastern area, associated with diorite intrusions. The central portion of the study area is dominated by low gravity anomalies, which correlate with Quaternary deposits such as colluvium and younger Merapi volcanic products. Specifically, the Nanggulan Formation exhibits a distinct low anomaly bounded by high anomalies, a pattern that aligns well with forward modeling results. These results propose that the uplift of the Nanggulan Formation is expected to be caused by a dike intrusion process, with the formation behaving as a roof overhanging within the regional tectonic and magmatic framework of the area.

Article Details

Gravity Data Analysis on the Emergence of the Nanggulan Formation in Kulon Progo Mountain

Authors:

Muhammad Faizal Zakaria | Sari Bahagiarti Kusumayudha | Y. Yatini | Ismail Mutoriz | Bobby Wijaya

Publisher:

Iraqi Geologists Union (Union of Iraqi Geologists)

Journal:

The Iraqi Geological Journal Vol.58 Issue 2C, pp.202-214

Document Type:

Article

Publication Date:

9/2025

Document Language:

English

Document ID (Org No.):

2001836882

pISSN:

2663-8754

Gravity method

CBA

Kulon progo

Nanggulan Formation

Roof pendant

Issues

Article Details

Gravity Data Analysis on the Emergence of the Nanggulan Formation in Kulon Progo Mountain

Authors: Muhammad Faizal Zakaria | Sari Bahagiarti Kusumayudha | Y. Yatini | Ismail Mutoriz | Bobby Wijaya

Publisher: Iraqi Geologists Union (Union of Iraqi Geologists)

Journal: The Iraqi Geological Journal Vol.58 Issue 2C, pp.202-214

Document Type: Article

Publication Date: 9/2025

Document Language: English

Document ID (Org No.): 2001836882

pISSN: 2663-8754

Gravity method

CBA

Kulon progo

Nanggulan Formation

Roof pendant

Issues

Authors:

Muhammad Faizal Zakaria | Sari Bahagiarti Kusumayudha | Y. Yatini | Ismail Mutoriz | Bobby Wijaya

Publisher:

Iraqi Geologists Union (Union of Iraqi Geologists)

Journal:

The Iraqi Geological Journal Vol.58 Issue 2C, pp.202-214

Document Type:

Article

Publication Date:

9/2025

Document Language:

English

Document ID (Org No.):

2001836882

pISSN:

2663-8754